Back in the summer of 1981, only 18 at the time, I bought a Sony C7 Betamax, that machine cost me £715, which would be around £2500 to £3000 today. Back then nothing was close to the picture quality of the recordings, and believe or not one of the first home VCR's to have colour picture search and slow motion playback, by the time the C9 with (HiFi Stereo) came out some 3 or 4 years later, getting rental films in Beta was quite difficult, so I didn't see the point in upgrading to the new model. Around 1987/88 the C7 finally gave up and was replaced be a VHS Panasonic. However, I still felt even after all that time and improvements to the VHS system the original C7 offered better picture quality recordings. Thanks for this insight into the world of build quality video tape recorders rarely seen....
@tymiklic646315 сағат бұрын
Wow..amazing beautiful picture..so gentle and not harsh..those Sony engineers really are something.love to see more pro audio gear too.. Love your crazy obsession with this astonishing gear.. Cheers..Ty from s.oz
@davidcocks2403Күн бұрын
My dad worked for NCR and gave us a techwctronix 555 4 trace oscilloscope what tech for the 1950s or early 1960s when it was built service able and. Working into the 1990s when we got it from our dad. Your equiet ent shows how engineering won over cost.
@senilyDeluxeКүн бұрын
Btw. could this be the earliest full logic controlled VCR? All VHS or Betamax machines I know of had mechanical switches before 1981. (also - professional use VCRs don't count)
@video99coukКүн бұрын
I think this is newer than the Sony SL-C7.
@jchunterКүн бұрын
The professionally-targeted Grundig VCR601/Philips LDL-1100 portable VCR format machine was incredibly advanced for 1977 and had a logic-controlled transport. If that's a little esoteric, there's the domestic market VCR-LP format Grundig VCR4000 which predated the SVR4004. The VCR4000 and SVR4004 were externally very similar, with the latter differing internally to handle the needs of the higher density SVR recording format.
@jchunterКүн бұрын
Almost forgot: Grundig had a VCR format machine targeted to the domestic market: the BK 3000. Externally clearly of the same lineage as their VCR4000 and SVR4004, also with a fully logic controlled transport. I think this model appeared in 1976, one year before the VCR601.
@senilyDeluxeКүн бұрын
@@video99couk I have an SL-C7E and it was early 80s. Internet says it came out in '79 so the SVR4004 is a bit older. I actually grew up on an SL-C6E which 4 year old me inserted a buttered toast (my parents had to tape a straw to the vacuum to get the crumbs out of the mechanism...), I thought the C6 would be the predecessor of the C7. Although the C7 looks decidedly more retro, it has more functions. And almost identical circuit boards. They both have the same problem: No control track / capstan lock. Whenever I take them apart and start scoping around, as soon as I get close to where the problem is, the problem just disappears and they just start working again. Even after reassembly. Until I stop using them for a few days. Sounds like capacitor, doesn't it?
@senilyDeluxeКүн бұрын
@@jchunter Whoa! Awesome info! Still it looks as if that doesn't change history - it still looks like it's Grundig who invented the full logic VCR. *sigh* back when Grundig was World Class... in the 80s they quickly became irrelevant and then the cheap far-eastern companies finally took over. In 1973 they came out with a 14 inch / 37cm portable colour TV that was fully solid state (neon indicator bulbs for the channel selector also don't count - the HV rectifier/tripler is also solid state) and used a (Toshiba made) in-line CRT. Very modern... apart from the power consumption... 110W... compare that to the late 90s, they were down to 35W on the same screen size. (still, compared to the 160-250W a similar sized tube colour TV had)
@douglashoff95Күн бұрын
These tape cartridges look a bit similar to the Quasar "Great Time Machine" marketed here in the US back in the late 1970's.
@video99coukКүн бұрын
They look similar. But the N1500, N1700, SVR formats all recorded full field video so were "modern" video formats. The Quasar system was skip field so it dumped half the video information.
@richrootes2 күн бұрын
Very nice, Colin - there are always people ready to criticize, just ignore them. Yours are some of the most enjoyable videos on KZread - if someone thinks they can do better, they should start their own channel
@senilyDeluxe2 күн бұрын
on mine, the light bulb is burnt out. The machine still works normally. Looks like you have pretty much the same recording on that test tape as I have...
@scusa2 күн бұрын
Can this method be used for Toshiba VHS/HDD/DVD multi? So instead of going through the dvd to get the digitalized vhs, I can access the vhs tape directly from the hdd.
@video99couk2 күн бұрын
Probably, yes.
@dominik.jokiel2 күн бұрын
Schachtkontakt; i would say that is a contact which switched if the door is closed or a cassete is inside
@vintagecameras96232 күн бұрын
I have one my shorts
@vintagecameras96232 күн бұрын
Thank you
@more.power.2 күн бұрын
Thank you Colin excellent work
@organfairy2 күн бұрын
I remember Sam from 'Look mom no computer' did a song and dance with the lyrics "you don't know what you're doing" as a reply to all those who made comments on his working methods in repairing an old church organ he had bought.
@binarydinosaurs2 күн бұрын
Given that this is the level of repair I do on vintage computers I was well entrenched in this. Must admit I was slightly disappointed when you didn't airpunch or dance around the room when it started playing properly :D Good stuff, cheers!
@TigerBoyRS2 күн бұрын
Brilliant, a little dark capacitor was found guilty! That machine is looking good and playing a nice picture. Colin just keeps on pulling these old vcr rarities back to life. Cheers 🍷
@jameswarner35992 күн бұрын
Nicely done sir. Nothing like a little logic and some perseverance. Well done 👍
@stefancarlberg78062 күн бұрын
Manual tracking with meter that you see signalstrenght you have on JVC HR-S 5000 SVHS come out 1988 . Very good to use with some tapes .
@video99couk2 күн бұрын
I wasn't aware of that feature on a JVC. Actually I think I may have owned a new one of those for a couple of weeks, back in the day. It kept breaking down and I replaced it with a NV-HS88 which was reliable (it still works!). So I never got to learn about all the JVC's features.
@bobsbits53572 күн бұрын
hi know about the trolls you get some people i know told me your having a channel is likely get alot of them yes i work on audio gear i have a brenel mini 8 i have working just waiting for pinch rollers to come back i have all the plans for it you know that hit a mole game very like that the repairs keep pop up all the time i am winning the game now there a sound craft 381- 8 for sell best not to buy it 200 uk just to get it going been there with a 600 reel to reel this video is not a money pit just like that game love the video's keep them coming
@cromulence3 күн бұрын
Great fault finding - so satisfying!
@Mrlaurens19873 күн бұрын
Good job and those people that complain are big mouths that dont know what they are doing
@Ragnar85043 күн бұрын
I tried my best to translate the pinout. Schacht is usually a narrow pit or a (mine) shaft but in this instance it's the cassette well. Fuehler (more usually spelled with an umlaut ü instead of ue) means sensor, error would be "Fehler". In a decent effort to make everything sound complicated, the Grundig engineers used the word for the tape type detection switch. The "Schachtkontakt" tells the machine whether the cassette tray is up or down. If that's constantly pulled low by a faulty capacitor, the machine gets confused. 1 - Locating hole 2 - GND 3 - +15 VE 4 - Flashing indicator (whatever that may be) 5 - Cass button (eject) 6 - Indicator „Cass“ (no tape) 7 - Play button and indicator 8 - FFwd button and LED 9 - Rew button and LED 10 - Stop button and LED 1 - Timer Record Start 2 - Timer Rec button 3 - 4 - Rec signal to power supply 5 - Tape end switch 6 - Rec button 7 - 50 Hz 8 - S1-B 9 - +15VR 10 - 11 - Y attenuation 12 - S2A 13 - FFwd signal 14 - S3 15 - 16 - N1 17 - GND 18 - N2 19 - Locating pin 20 - +15VE 21 - 22 - Cassette (type detect) switch 23 - On/off relay 24 - Cassette tray switch 25 - 26 - Unlace 27 - Play 28 - Rew 29 - Lace
@TTVEaGMXde3 күн бұрын
S stands for Sibatit (SIEMENS ceramic type) capacitor. Capacitor or IC, the main thing is that SIEMENS is to blame. I have already written that you should only keep SVC recorders in a pack so that you can try out which one suits the recording device best. Market researchers have advised Max Grundig against SVC recorders. The ITT Videorecorder 241 is the rarest variant of this evolutionary dud. Since the transistor has a 100k Ohm resistor and the IC has a 6.8K Ohm resistor, the capacitor was the most likely cause. But as a TV Engineer, I wouldn't have found the problem any faster. Well done👍
@video99couk3 күн бұрын
That's right, machine/tape inter-operability was not a given on this format.
@manolomos3 күн бұрын
The sound of heads at minute 17 is caused by an excessive tension of the tape. In spite the video has an optimal calibration from factory, maybe is necesary to adjust and loose a bit the tension of tape, because the tapes are subject to ageing and the sliding is not good as it should be. It can be a nightmare to adjust differently the tension adjust for every tape, but it happens, some too loose, some too tenses. Edit: Tension adjust is at page 12 figure Ab.7.1. Sometimes there is another problem, tape tension is not the same at the beginning then at the of the tape.
@video99couk3 күн бұрын
It settled down after a few minutes, but yes the back tension arm was bouncing around a bit at first.
@manolomos3 күн бұрын
@@video99couk So, in that case, apply the gold law: If it works, don't touch it. Another tip: Capstan motor screws are not torqued at the end. This screws are part of some kind of capstan angle adjust, so, don't touch it. You can see it at 2.8 "wechsel des captanmotors" page 20.
@frankowalker46623 күн бұрын
Nice work. Time consuming, but worth it for a rare machine. (I think the mechanism could do with some oil. LOL.)
@custardpie693 күн бұрын
I see you are a Techmoan fan too..
@custardpie693 күн бұрын
This is my kinda ultra-geeky stuff…. Good on ya mate
@RebeccaTurner-ny1xx3 күн бұрын
Such careful and difficult work! Ultimately of course it's a futile battle against the basic entropy of the universe that pushes everything towards disorder and chaos. But we can gain temporary victories such as repairing obsolete video machines. It's a pleasure to see this.
@video99couk3 күн бұрын
Always seem to be fighting that entropy problem.
@ViegasSilva3 күн бұрын
lots of static it seems 😏
@JacGoudsmit3 күн бұрын
A little faulty component can have big consequences. Great job! Thanks for posting.
@theprogrammerrolandmc30394 күн бұрын
tascam pcb's are awful the transport on 2488 all series of multitracks especially the mk2 are bendy and traces lift they are transport supposed to be pressed down on when tactile switches fail people press down even harder. if only they would copy the schematics and send them to pcb way so we could order a blank and repopulate them. Right to repair yeah right Tascam
@lavectech4 күн бұрын
Keen for the Powerwall 3 here in Australia for a new install with inverter integrated.
@video99couk4 күн бұрын
Yes the Powerwall 3 makes sense on a new install. I understand that it's now available in the UK so shouldn't be long behind in Oz. Really it's not so much an integrated inverter, as no inverter. The only inverter is on the output side of the battery, just like any other Powerwall. They are deleting the DC from solar to AC and then back to DC for battery charging, which makes a lot of sense. There will still have to be some DC to DC management for battery charging, but that will likely be a high frequency (efficient) system.
@manolomos4 күн бұрын
My SVR4004 had some faults. Symthom: When the video is hot, some reels stops suddenly. Cause, in "motorelektronik" card, TR1363, TR1358. In manual service is BD898 but in my Grundig was TIP121. Just replace. The cause is that when the transistor is hot, internal junction fails. Symthom: Hardly seen green and violet vertical bars. Maybe is needed to adjust Chroma filter, but I solved it adjusting R1811 in chroma card to maximum. Symthom: Low signal in tracking indication. Low amplification by IC1683 TDA2700 in Chroma card? Just replace. I found some rubber rottens with cushion fuctions, I replace it with cable gland rubber. This are used in the reels motors and threading mechanism motors. A "must do" is to replace Roe Roederstein capacitors. Another faulty capacitors are tiny axial Philips caps, mostly in sound card. Note: I've tried convencional VCR tapes, and some tapes with VHS and Beta belts, and works perfectly like "Grundig high density tapes for SVR4004". So, I think there is no a real reason for to use different tapes in this video than in other VCR older video tapes. I think that "Grundig high density vcr tape" was a bullshit for comercial reasons.
@video99couk4 күн бұрын
Another component level repair on these machines will be released tomorrow.
@detectivedreams5 күн бұрын
THANK YOU SO MUCH, this information is gold
@hankshanklin6 күн бұрын
There's something I've been wondering for a while now,& judging by the subject of this video, I think you're the person best placed to answer it. Beta had cleaner tapes are pretty highly priced these days, often reaching over £40. Vhs cleaner tapes are much cheaper. So, as the tapes are the same size, can I slice a section from a vhs cleaner into an empty beta chassis? Or would you just suggest cleaning the heads by hand?
@video99couk6 күн бұрын
There's no harm at all in transplanting a VHS head cleaner into a Beta shell. If you can splice onto the foil leader tape, then the proper auto stop will function too. If you can't get a spare Betamax shell, a small Betacam BetacamSP shell will work just fine too.
@clyth416 күн бұрын
I've come to the conclusion that Betamax sucks.. Lol... I feel your pain bro... 😢😊
@video99couk6 күн бұрын
I wouldn't say that. VHS machines of the same age can be just as troublesome. And V2000 are invariably much worse.
@laserfilmlab6 күн бұрын
It's too bad that no one can have access to your equipment to de mold tape.
@video99couk6 күн бұрын
Really it's just a couple of motors, lashed up spool holders and a bench power supply.
@laserfilmlab6 күн бұрын
@@video99couk maybe you can show it again and do another tutorial on that? Please Your channel is one of the better ones out on youtube. Thanks
@randomsteve42886 күн бұрын
30:59 looking at the mechanism and PCB this was not really made by Grundig. The mechanism with the microswitches gives a strong JVC vibe and the chipset on the PCB is Hitachi and the Electrolytics Made in Japan. If it was a Grundig designed gear the higher level signal chips would be Philips/Valvo or Siemens and the caps Frako or ERO.
@video99couk6 күн бұрын
Since Funai made the first generation of CVC machines, it's quite likely they were involved in the Grundig model too, but they never marketed that improved version.
@janosnagyj.95406 күн бұрын
Wow, what a trip! Yeah those 723s are always a pain in the arse... when you show it the first time on the diagram I was like noooooo... a 723 😅 But it's strange why something was smoking, on the top part of the circuit there is an "electronic fuse" which through that SCR disables the output in case of overcurrent - at least, it should do that...🙄 So basically we had a dead 723 to begin with, and then that tantalum got shocked when it saw again some electrons after who knows how many years of total darkness 🤣And now something else gave up again. Maybe another tantalum had enough? 🙄 Can't wait the next episode 😅
@video99couk6 күн бұрын
The smoke should not have happened with the SCR in there.
@theprogrammerrolandmc30396 күн бұрын
ADAT is a repairman's dream machine and only repair men should own them if they get it to play once then put it away so they can repair it again when they try to use it next time the florescent vacuum displays are highly sought after as they can't be repaired
@video99couk6 күн бұрын
It's old equipment now and failures are to be expected. Fortunately I can keep this kit going, and also Tascam DTRS machines which are of a similar vintage and also break down.
@theprogrammerrolandmc30395 күн бұрын
@@video99couk I would love a ADAT machine i have everything from Reel to Reel cassette multi tracks. But the 90's equipment are verging on unrepeatable i have a Fostex 1624 mk2 similar to Alesis HD you have a great machine but the fostex is quite rare florescent display went out and i have been going thru everything on it suspect a power supply component. but so many IC's and processors very difficult and time consuming. I really appreciate your video as it's great to see old equipment working.
@guimbadriver6 күн бұрын
wow i never saw it in my short life...look this mechanics 4 heavy driver motors two big motors must be drum and capstan others one must be reel and loading
@video99couk6 күн бұрын
Actually two reel motors with electronic back tension.
@guimbadriver6 күн бұрын
@@video99couk wow professional tape transport looks like my JVC CR 850 U U matic VCR
@randomsteve42887 күн бұрын
13:55 Without going into detail let it be said that to construct a proper oscilloscope probe attenuation devider you not only need a resistive devider scaling down the DC, you also need to use caps in parallel to the resistor to provide a scaled down path for your AC component. If you dont add any caps the input capacitance of ur scope to ground will form a low pass filter along with your high side atennuation resistor. What you get is a waveform that has low frequency response, no definition or sharp transitions or edges. Just look up the schematics of an average scope probe with inbuilt attenuators, watch the eevblog videos on homebuilt attenuation probes or refer to the literature on passive scope attenuation probes on for example the Rohde+Schwarz website. With your scope being only 5Vpp input you should really invest in a 1:100 attenuator probe. It will not only increase the useable voltage range on the scope x100 but also (and often most importantly) reduce both the capacitive and resistive loading down on the circuit under test by x100.
@johncunningham35477 күн бұрын
Does the fibre install have issues with Mac addresses?
@video99couk7 күн бұрын
No. But their system does need to know your Mac address, so if they don't supply the router (as they did for us) then they have to know that.
@randomsteve42887 күн бұрын
49:52 I highly doubt that there is a design flaw in the Reset IC. If you had looked more closely at the schematic, you may have noticed that this IC does not only trigger on Power On, but also on an undervoltage condition in the 5V +5b line. It is clearly shown that this IC 1453-2A uses a precision zener TL431 to derive a 2,56V reference voltage on pin 17, to which the +5b line is compared ( via an internal voltage devider..). If your 5 V supply is marginal or glitching or has hum on it, it may very well cause the IC to keep in reset. Same goes for the TL431 having drifted high in its zener voltage. Since with a too high reference, the release point of this IC would shift upwards too, waiting for 5V which cant be reached. And here is another hint; even tho temperature compensated, if you heat a TL431 its reference voltage generally drops slightly. So the IC woukd release the reset at a lower +5b... Now where have we experienced that? Oh right thats exactly how this circuit behaved! Sorry but instead of altering the circuit it would be a matter of seconds to rig up a TL431 and test the deemed defective IC on a regulated adjustable 5V bench power supply for both the undervoltage lockout trigger and reset release voltage. That way you could get 1000% confirmatuon if the IC is faulty or marginal, or if with your POR redesign you merely coveted up the underlying cause. PS especially if the blue trace in the scope picture at 51:43 shows ur +5B line! Its amplitude rises by only 4,8 devisions on a 1V/ div scope scale. That tells me that your +5b wpuld be 4,8 to 4,9V and not 5V or 5,2V (which most of the Grundig V2000 run their logic boards on).
@video99couk7 күн бұрын
The 5V line was clean. My POR circuit did the job but unfortunately the repair was ultimately defeated by a problem deep in the DTF circuit. In the end this machine ended up supplying parts to make up another machine of the same model which is now in regular service.
@randomsteve42887 күн бұрын
12:09 Calling a uPC574 a voltage source is kind of wrong. It is a temperature drift compensated 33V zener used to stabilize the tuning voltage feed on tuners. So unless that craptastic tester puts out more than 33V, the uPC574 will always be recognized as a simple diode only.
@robertlloyd-jones43107 күн бұрын
Great video Colin, I love these in depth videos about real vintage technology. You have a lot of patience! You’ve inspired me to take another look at my machine (when I have a lot of spare time). The main fault on mine is that the capstan pinch wheel solenoid doesn’t engage in play. Any ideas which voltage might be missing? Cheers, Rob.
@video99couk7 күн бұрын
You'll have to wade through the service manual, especially around page 90 where all the timing diagrams are, to see why it's not being actuated.
@bobsbits53577 күн бұрын
hi them ohone vid's i just don't like please keep it to the same format i know it may get more watch i just turn it of
@video99couk7 күн бұрын
I'm not quite sure what you are saying, but I didn't change anything about the format of this video. I'm bound to cover some subjects which are less or more interesting to different people each week. It's very important that I do different subjects in order to attract more subscribers over time.
@markedwards48797 күн бұрын
18:14 The Firmware in the UK models must be different to what we have here in Australia. When our grid fails the power wall switchover is instant. I do have UPS'es connected to most computer equipment anyway but the most that we get is a single beep from them as they report the the grid did something. No lights flicker and machines not on the UPS don't even notice the switch. Ironically I'm sitting here typing this while the house is off grid since there is scheduled work out on the street. It's winter here and the sun is very low so shading on my solar array from surrounding trees is terrible, but the house is running as normal with the heat pump (reverse cycle air conditioning) is keeping the house a 21º with free solar energy. If the battery gets full it regulates the solar automatically by slightly raising its output frequency. All very seamless.
@video99couk7 күн бұрын
It's certainly not seamless here, the power goes off for about a second before the Powerwall kicks in. Maybe you have a newer Tesla Gateway which can switch over quicker. It would certainly be better if it were almost instant.
@markedwards48797 күн бұрын
@@video99couk I have a gen 2 gateway, which version do you have?
@miroslawkaras77107 күн бұрын
If sombody like to have almost perfect wow aflater test cattet tape it shoul be order from high speed duplicators that copy the tape up to 100 time daster,. So any wow and flater is almost non exitance. The source of frequency is RF generator. That might be more inportant for speed ajustment. If you like to mesure just wow and flater take the casette tape and record the signal from computer and play and measure on the meter. The number that you get from the wow and flater meter just divide by two. This will be the most accurate measurement that you can make on your tape recorder no mater what profetionaly done tape you will obtain.
@video99couk7 күн бұрын
It may not be exactly divide by two for a self-generated tape, but in that order of things. If your cassette deck has a cyclical wow, then it could cancel itself out and imply that it's better than it is.
@randomsteve42887 күн бұрын
40:03 I hate to throw a wrench into your troubleshooting, but there should not have been any smoke escaping at this point. The 15V regulator is protected by a feature called electronic fuse "ELEKTRONISCHE SICHERUNG". And this electronic fuse is build around the thyristor/scr TY447 2N5081G. And this protection works as follows; TY447 monitors the voltage drop across the resistor R451 (0R22). If the output current rises the voltage drop across R451 increases. If that voltage across R451 exceeds the Gate to Cathode trigger voltage of TY447, the SCR conducts and puts a positive voltage from the raw 22,6V line via R443 onto the node of R446/R447 and thus effectively pulling pin 2 of the uA723 high. As a result the uA723 has to immediately switch off any base drive to the pass transistor T449, and the whole 15V output will shut down. The cleverness with this circuit is that it latches the supply in the shut off mode and will not let it come back up, even if the short disappears. Why is that so? Because like any thyristor SCR TY447 will stay conductive as long as it has any Anode to Cathode current flowing through it, even if the Gate drive (hence excessive output current thru R451) disappears. As a result after an overcurrent trigger event, the pin 2 on the uA723 will stay pulled high and the 15V supply will stay shut down until the whole VCR is fully power cycled. I wonder where we did see this behavior... Oh right, the previous Grundig SVR 4004 did exactly behave like that; the 15V line IMMEDIATELY shut down on the overload caused by the bad tantalum and stayed shut down until a power cycle. What this means for this VCR is, that either this powersupply board is a different revision missing this electronic fuse feature (I hardly think so), or the SCR TY447 is bad or was disabled by a previous tech troubleshooting, or the "NEW" uA723 that you fitted does not handle the signal to pin 2 correctly, meaning it is a fake. The latter can be proven easily by upon proper operation passing voltage from the 22,6V rail thru a 1,5k resistor into the node of R446 and R447, and watching if the 15V line shuts down. Whatever you do, Bottomline is; The 7V you saw on the 15V rail before the smoke escaped should never have happened. The overload shutdown should have kicked in instantly and lasted until cycling the power. Just like seen on the previous 4004. Seeing how these VCR are prone to problems with tentalums on the 15 Volt line shorting out, I strongly suggest investigating into why this powersupply did not shut down the 15V rail on overload properly, unless you want to fit a fuse in the 22,6V rail to make up for that protection feature not working. Side note; Why didn't you use a current limited(!!!) bench powersupply to externally feed the 15V rail? You could have easily seen how much current was drawn and which module was the culprit.
@video99couk7 күн бұрын
I am concerned about fake UA723 chips and will buy some from a reputable supplier, so could replace that later. The smoke was certainly a bad thing and I would want to avoid that risk again. I will be working on the machine again very soon: I'm fairly sure that the failure to operate deck functions is caused by another tantalum capacitor having failed. I'm not keep on using the bench power supply route, it could result in currents flowing where they should not since the machine's design may assume some 15V rails are only present when others are.
Пікірлер
Back in the summer of 1981, only 18 at the time, I bought a Sony C7 Betamax, that machine cost me £715, which would be around £2500 to £3000 today. Back then nothing was close to the picture quality of the recordings, and believe or not one of the first home VCR's to have colour picture search and slow motion playback, by the time the C9 with (HiFi Stereo) came out some 3 or 4 years later, getting rental films in Beta was quite difficult, so I didn't see the point in upgrading to the new model. Around 1987/88 the C7 finally gave up and was replaced be a VHS Panasonic. However, I still felt even after all that time and improvements to the VHS system the original C7 offered better picture quality recordings. Thanks for this insight into the world of build quality video tape recorders rarely seen....
Wow..amazing beautiful picture..so gentle and not harsh..those Sony engineers really are something.love to see more pro audio gear too.. Love your crazy obsession with this astonishing gear.. Cheers..Ty from s.oz
My dad worked for NCR and gave us a techwctronix 555 4 trace oscilloscope what tech for the 1950s or early 1960s when it was built service able and. Working into the 1990s when we got it from our dad. Your equiet ent shows how engineering won over cost.
Btw. could this be the earliest full logic controlled VCR? All VHS or Betamax machines I know of had mechanical switches before 1981. (also - professional use VCRs don't count)
I think this is newer than the Sony SL-C7.
The professionally-targeted Grundig VCR601/Philips LDL-1100 portable VCR format machine was incredibly advanced for 1977 and had a logic-controlled transport. If that's a little esoteric, there's the domestic market VCR-LP format Grundig VCR4000 which predated the SVR4004. The VCR4000 and SVR4004 were externally very similar, with the latter differing internally to handle the needs of the higher density SVR recording format.
Almost forgot: Grundig had a VCR format machine targeted to the domestic market: the BK 3000. Externally clearly of the same lineage as their VCR4000 and SVR4004, also with a fully logic controlled transport. I think this model appeared in 1976, one year before the VCR601.
@@video99couk I have an SL-C7E and it was early 80s. Internet says it came out in '79 so the SVR4004 is a bit older. I actually grew up on an SL-C6E which 4 year old me inserted a buttered toast (my parents had to tape a straw to the vacuum to get the crumbs out of the mechanism...), I thought the C6 would be the predecessor of the C7. Although the C7 looks decidedly more retro, it has more functions. And almost identical circuit boards. They both have the same problem: No control track / capstan lock. Whenever I take them apart and start scoping around, as soon as I get close to where the problem is, the problem just disappears and they just start working again. Even after reassembly. Until I stop using them for a few days. Sounds like capacitor, doesn't it?
@@jchunter Whoa! Awesome info! Still it looks as if that doesn't change history - it still looks like it's Grundig who invented the full logic VCR. *sigh* back when Grundig was World Class... in the 80s they quickly became irrelevant and then the cheap far-eastern companies finally took over. In 1973 they came out with a 14 inch / 37cm portable colour TV that was fully solid state (neon indicator bulbs for the channel selector also don't count - the HV rectifier/tripler is also solid state) and used a (Toshiba made) in-line CRT. Very modern... apart from the power consumption... 110W... compare that to the late 90s, they were down to 35W on the same screen size. (still, compared to the 160-250W a similar sized tube colour TV had)
These tape cartridges look a bit similar to the Quasar "Great Time Machine" marketed here in the US back in the late 1970's.
They look similar. But the N1500, N1700, SVR formats all recorded full field video so were "modern" video formats. The Quasar system was skip field so it dumped half the video information.
Very nice, Colin - there are always people ready to criticize, just ignore them. Yours are some of the most enjoyable videos on KZread - if someone thinks they can do better, they should start their own channel
on mine, the light bulb is burnt out. The machine still works normally. Looks like you have pretty much the same recording on that test tape as I have...
Can this method be used for Toshiba VHS/HDD/DVD multi? So instead of going through the dvd to get the digitalized vhs, I can access the vhs tape directly from the hdd.
Probably, yes.
Schachtkontakt; i would say that is a contact which switched if the door is closed or a cassete is inside
I have one my shorts
Thank you
Thank you Colin excellent work
I remember Sam from 'Look mom no computer' did a song and dance with the lyrics "you don't know what you're doing" as a reply to all those who made comments on his working methods in repairing an old church organ he had bought.
Given that this is the level of repair I do on vintage computers I was well entrenched in this. Must admit I was slightly disappointed when you didn't airpunch or dance around the room when it started playing properly :D Good stuff, cheers!
Brilliant, a little dark capacitor was found guilty! That machine is looking good and playing a nice picture. Colin just keeps on pulling these old vcr rarities back to life. Cheers 🍷
Nicely done sir. Nothing like a little logic and some perseverance. Well done 👍
Manual tracking with meter that you see signalstrenght you have on JVC HR-S 5000 SVHS come out 1988 . Very good to use with some tapes .
I wasn't aware of that feature on a JVC. Actually I think I may have owned a new one of those for a couple of weeks, back in the day. It kept breaking down and I replaced it with a NV-HS88 which was reliable (it still works!). So I never got to learn about all the JVC's features.
hi know about the trolls you get some people i know told me your having a channel is likely get alot of them yes i work on audio gear i have a brenel mini 8 i have working just waiting for pinch rollers to come back i have all the plans for it you know that hit a mole game very like that the repairs keep pop up all the time i am winning the game now there a sound craft 381- 8 for sell best not to buy it 200 uk just to get it going been there with a 600 reel to reel this video is not a money pit just like that game love the video's keep them coming
Great fault finding - so satisfying!
Good job and those people that complain are big mouths that dont know what they are doing
I tried my best to translate the pinout. Schacht is usually a narrow pit or a (mine) shaft but in this instance it's the cassette well. Fuehler (more usually spelled with an umlaut ü instead of ue) means sensor, error would be "Fehler". In a decent effort to make everything sound complicated, the Grundig engineers used the word for the tape type detection switch. The "Schachtkontakt" tells the machine whether the cassette tray is up or down. If that's constantly pulled low by a faulty capacitor, the machine gets confused. 1 - Locating hole 2 - GND 3 - +15 VE 4 - Flashing indicator (whatever that may be) 5 - Cass button (eject) 6 - Indicator „Cass“ (no tape) 7 - Play button and indicator 8 - FFwd button and LED 9 - Rew button and LED 10 - Stop button and LED 1 - Timer Record Start 2 - Timer Rec button 3 - 4 - Rec signal to power supply 5 - Tape end switch 6 - Rec button 7 - 50 Hz 8 - S1-B 9 - +15VR 10 - 11 - Y attenuation 12 - S2A 13 - FFwd signal 14 - S3 15 - 16 - N1 17 - GND 18 - N2 19 - Locating pin 20 - +15VE 21 - 22 - Cassette (type detect) switch 23 - On/off relay 24 - Cassette tray switch 25 - 26 - Unlace 27 - Play 28 - Rew 29 - Lace
S stands for Sibatit (SIEMENS ceramic type) capacitor. Capacitor or IC, the main thing is that SIEMENS is to blame. I have already written that you should only keep SVC recorders in a pack so that you can try out which one suits the recording device best. Market researchers have advised Max Grundig against SVC recorders. The ITT Videorecorder 241 is the rarest variant of this evolutionary dud. Since the transistor has a 100k Ohm resistor and the IC has a 6.8K Ohm resistor, the capacitor was the most likely cause. But as a TV Engineer, I wouldn't have found the problem any faster. Well done👍
That's right, machine/tape inter-operability was not a given on this format.
The sound of heads at minute 17 is caused by an excessive tension of the tape. In spite the video has an optimal calibration from factory, maybe is necesary to adjust and loose a bit the tension of tape, because the tapes are subject to ageing and the sliding is not good as it should be. It can be a nightmare to adjust differently the tension adjust for every tape, but it happens, some too loose, some too tenses. Edit: Tension adjust is at page 12 figure Ab.7.1. Sometimes there is another problem, tape tension is not the same at the beginning then at the of the tape.
It settled down after a few minutes, but yes the back tension arm was bouncing around a bit at first.
@@video99couk So, in that case, apply the gold law: If it works, don't touch it. Another tip: Capstan motor screws are not torqued at the end. This screws are part of some kind of capstan angle adjust, so, don't touch it. You can see it at 2.8 "wechsel des captanmotors" page 20.
Nice work. Time consuming, but worth it for a rare machine. (I think the mechanism could do with some oil. LOL.)
I see you are a Techmoan fan too..
This is my kinda ultra-geeky stuff…. Good on ya mate
Such careful and difficult work! Ultimately of course it's a futile battle against the basic entropy of the universe that pushes everything towards disorder and chaos. But we can gain temporary victories such as repairing obsolete video machines. It's a pleasure to see this.
Always seem to be fighting that entropy problem.
lots of static it seems 😏
A little faulty component can have big consequences. Great job! Thanks for posting.
tascam pcb's are awful the transport on 2488 all series of multitracks especially the mk2 are bendy and traces lift they are transport supposed to be pressed down on when tactile switches fail people press down even harder. if only they would copy the schematics and send them to pcb way so we could order a blank and repopulate them. Right to repair yeah right Tascam
Keen for the Powerwall 3 here in Australia for a new install with inverter integrated.
Yes the Powerwall 3 makes sense on a new install. I understand that it's now available in the UK so shouldn't be long behind in Oz. Really it's not so much an integrated inverter, as no inverter. The only inverter is on the output side of the battery, just like any other Powerwall. They are deleting the DC from solar to AC and then back to DC for battery charging, which makes a lot of sense. There will still have to be some DC to DC management for battery charging, but that will likely be a high frequency (efficient) system.
My SVR4004 had some faults. Symthom: When the video is hot, some reels stops suddenly. Cause, in "motorelektronik" card, TR1363, TR1358. In manual service is BD898 but in my Grundig was TIP121. Just replace. The cause is that when the transistor is hot, internal junction fails. Symthom: Hardly seen green and violet vertical bars. Maybe is needed to adjust Chroma filter, but I solved it adjusting R1811 in chroma card to maximum. Symthom: Low signal in tracking indication. Low amplification by IC1683 TDA2700 in Chroma card? Just replace. I found some rubber rottens with cushion fuctions, I replace it with cable gland rubber. This are used in the reels motors and threading mechanism motors. A "must do" is to replace Roe Roederstein capacitors. Another faulty capacitors are tiny axial Philips caps, mostly in sound card. Note: I've tried convencional VCR tapes, and some tapes with VHS and Beta belts, and works perfectly like "Grundig high density tapes for SVR4004". So, I think there is no a real reason for to use different tapes in this video than in other VCR older video tapes. I think that "Grundig high density vcr tape" was a bullshit for comercial reasons.
Another component level repair on these machines will be released tomorrow.
THANK YOU SO MUCH, this information is gold
There's something I've been wondering for a while now,& judging by the subject of this video, I think you're the person best placed to answer it. Beta had cleaner tapes are pretty highly priced these days, often reaching over £40. Vhs cleaner tapes are much cheaper. So, as the tapes are the same size, can I slice a section from a vhs cleaner into an empty beta chassis? Or would you just suggest cleaning the heads by hand?
There's no harm at all in transplanting a VHS head cleaner into a Beta shell. If you can splice onto the foil leader tape, then the proper auto stop will function too. If you can't get a spare Betamax shell, a small Betacam BetacamSP shell will work just fine too.
I've come to the conclusion that Betamax sucks.. Lol... I feel your pain bro... 😢😊
I wouldn't say that. VHS machines of the same age can be just as troublesome. And V2000 are invariably much worse.
It's too bad that no one can have access to your equipment to de mold tape.
Really it's just a couple of motors, lashed up spool holders and a bench power supply.
@@video99couk maybe you can show it again and do another tutorial on that? Please Your channel is one of the better ones out on youtube. Thanks
30:59 looking at the mechanism and PCB this was not really made by Grundig. The mechanism with the microswitches gives a strong JVC vibe and the chipset on the PCB is Hitachi and the Electrolytics Made in Japan. If it was a Grundig designed gear the higher level signal chips would be Philips/Valvo or Siemens and the caps Frako or ERO.
Since Funai made the first generation of CVC machines, it's quite likely they were involved in the Grundig model too, but they never marketed that improved version.
Wow, what a trip! Yeah those 723s are always a pain in the arse... when you show it the first time on the diagram I was like noooooo... a 723 😅 But it's strange why something was smoking, on the top part of the circuit there is an "electronic fuse" which through that SCR disables the output in case of overcurrent - at least, it should do that...🙄 So basically we had a dead 723 to begin with, and then that tantalum got shocked when it saw again some electrons after who knows how many years of total darkness 🤣And now something else gave up again. Maybe another tantalum had enough? 🙄 Can't wait the next episode 😅
The smoke should not have happened with the SCR in there.
ADAT is a repairman's dream machine and only repair men should own them if they get it to play once then put it away so they can repair it again when they try to use it next time the florescent vacuum displays are highly sought after as they can't be repaired
It's old equipment now and failures are to be expected. Fortunately I can keep this kit going, and also Tascam DTRS machines which are of a similar vintage and also break down.
@@video99couk I would love a ADAT machine i have everything from Reel to Reel cassette multi tracks. But the 90's equipment are verging on unrepeatable i have a Fostex 1624 mk2 similar to Alesis HD you have a great machine but the fostex is quite rare florescent display went out and i have been going thru everything on it suspect a power supply component. but so many IC's and processors very difficult and time consuming. I really appreciate your video as it's great to see old equipment working.
wow i never saw it in my short life...look this mechanics 4 heavy driver motors two big motors must be drum and capstan others one must be reel and loading
Actually two reel motors with electronic back tension.
@@video99couk wow professional tape transport looks like my JVC CR 850 U U matic VCR
13:55 Without going into detail let it be said that to construct a proper oscilloscope probe attenuation devider you not only need a resistive devider scaling down the DC, you also need to use caps in parallel to the resistor to provide a scaled down path for your AC component. If you dont add any caps the input capacitance of ur scope to ground will form a low pass filter along with your high side atennuation resistor. What you get is a waveform that has low frequency response, no definition or sharp transitions or edges. Just look up the schematics of an average scope probe with inbuilt attenuators, watch the eevblog videos on homebuilt attenuation probes or refer to the literature on passive scope attenuation probes on for example the Rohde+Schwarz website. With your scope being only 5Vpp input you should really invest in a 1:100 attenuator probe. It will not only increase the useable voltage range on the scope x100 but also (and often most importantly) reduce both the capacitive and resistive loading down on the circuit under test by x100.
Does the fibre install have issues with Mac addresses?
No. But their system does need to know your Mac address, so if they don't supply the router (as they did for us) then they have to know that.
49:52 I highly doubt that there is a design flaw in the Reset IC. If you had looked more closely at the schematic, you may have noticed that this IC does not only trigger on Power On, but also on an undervoltage condition in the 5V +5b line. It is clearly shown that this IC 1453-2A uses a precision zener TL431 to derive a 2,56V reference voltage on pin 17, to which the +5b line is compared ( via an internal voltage devider..). If your 5 V supply is marginal or glitching or has hum on it, it may very well cause the IC to keep in reset. Same goes for the TL431 having drifted high in its zener voltage. Since with a too high reference, the release point of this IC would shift upwards too, waiting for 5V which cant be reached. And here is another hint; even tho temperature compensated, if you heat a TL431 its reference voltage generally drops slightly. So the IC woukd release the reset at a lower +5b... Now where have we experienced that? Oh right thats exactly how this circuit behaved! Sorry but instead of altering the circuit it would be a matter of seconds to rig up a TL431 and test the deemed defective IC on a regulated adjustable 5V bench power supply for both the undervoltage lockout trigger and reset release voltage. That way you could get 1000% confirmatuon if the IC is faulty or marginal, or if with your POR redesign you merely coveted up the underlying cause. PS especially if the blue trace in the scope picture at 51:43 shows ur +5B line! Its amplitude rises by only 4,8 devisions on a 1V/ div scope scale. That tells me that your +5b wpuld be 4,8 to 4,9V and not 5V or 5,2V (which most of the Grundig V2000 run their logic boards on).
The 5V line was clean. My POR circuit did the job but unfortunately the repair was ultimately defeated by a problem deep in the DTF circuit. In the end this machine ended up supplying parts to make up another machine of the same model which is now in regular service.
12:09 Calling a uPC574 a voltage source is kind of wrong. It is a temperature drift compensated 33V zener used to stabilize the tuning voltage feed on tuners. So unless that craptastic tester puts out more than 33V, the uPC574 will always be recognized as a simple diode only.
Great video Colin, I love these in depth videos about real vintage technology. You have a lot of patience! You’ve inspired me to take another look at my machine (when I have a lot of spare time). The main fault on mine is that the capstan pinch wheel solenoid doesn’t engage in play. Any ideas which voltage might be missing? Cheers, Rob.
You'll have to wade through the service manual, especially around page 90 where all the timing diagrams are, to see why it's not being actuated.
hi them ohone vid's i just don't like please keep it to the same format i know it may get more watch i just turn it of
I'm not quite sure what you are saying, but I didn't change anything about the format of this video. I'm bound to cover some subjects which are less or more interesting to different people each week. It's very important that I do different subjects in order to attract more subscribers over time.
18:14 The Firmware in the UK models must be different to what we have here in Australia. When our grid fails the power wall switchover is instant. I do have UPS'es connected to most computer equipment anyway but the most that we get is a single beep from them as they report the the grid did something. No lights flicker and machines not on the UPS don't even notice the switch. Ironically I'm sitting here typing this while the house is off grid since there is scheduled work out on the street. It's winter here and the sun is very low so shading on my solar array from surrounding trees is terrible, but the house is running as normal with the heat pump (reverse cycle air conditioning) is keeping the house a 21º with free solar energy. If the battery gets full it regulates the solar automatically by slightly raising its output frequency. All very seamless.
It's certainly not seamless here, the power goes off for about a second before the Powerwall kicks in. Maybe you have a newer Tesla Gateway which can switch over quicker. It would certainly be better if it were almost instant.
@@video99couk I have a gen 2 gateway, which version do you have?
If sombody like to have almost perfect wow aflater test cattet tape it shoul be order from high speed duplicators that copy the tape up to 100 time daster,. So any wow and flater is almost non exitance. The source of frequency is RF generator. That might be more inportant for speed ajustment. If you like to mesure just wow and flater take the casette tape and record the signal from computer and play and measure on the meter. The number that you get from the wow and flater meter just divide by two. This will be the most accurate measurement that you can make on your tape recorder no mater what profetionaly done tape you will obtain.
It may not be exactly divide by two for a self-generated tape, but in that order of things. If your cassette deck has a cyclical wow, then it could cancel itself out and imply that it's better than it is.
40:03 I hate to throw a wrench into your troubleshooting, but there should not have been any smoke escaping at this point. The 15V regulator is protected by a feature called electronic fuse "ELEKTRONISCHE SICHERUNG". And this electronic fuse is build around the thyristor/scr TY447 2N5081G. And this protection works as follows; TY447 monitors the voltage drop across the resistor R451 (0R22). If the output current rises the voltage drop across R451 increases. If that voltage across R451 exceeds the Gate to Cathode trigger voltage of TY447, the SCR conducts and puts a positive voltage from the raw 22,6V line via R443 onto the node of R446/R447 and thus effectively pulling pin 2 of the uA723 high. As a result the uA723 has to immediately switch off any base drive to the pass transistor T449, and the whole 15V output will shut down. The cleverness with this circuit is that it latches the supply in the shut off mode and will not let it come back up, even if the short disappears. Why is that so? Because like any thyristor SCR TY447 will stay conductive as long as it has any Anode to Cathode current flowing through it, even if the Gate drive (hence excessive output current thru R451) disappears. As a result after an overcurrent trigger event, the pin 2 on the uA723 will stay pulled high and the 15V supply will stay shut down until the whole VCR is fully power cycled. I wonder where we did see this behavior... Oh right, the previous Grundig SVR 4004 did exactly behave like that; the 15V line IMMEDIATELY shut down on the overload caused by the bad tantalum and stayed shut down until a power cycle. What this means for this VCR is, that either this powersupply board is a different revision missing this electronic fuse feature (I hardly think so), or the SCR TY447 is bad or was disabled by a previous tech troubleshooting, or the "NEW" uA723 that you fitted does not handle the signal to pin 2 correctly, meaning it is a fake. The latter can be proven easily by upon proper operation passing voltage from the 22,6V rail thru a 1,5k resistor into the node of R446 and R447, and watching if the 15V line shuts down. Whatever you do, Bottomline is; The 7V you saw on the 15V rail before the smoke escaped should never have happened. The overload shutdown should have kicked in instantly and lasted until cycling the power. Just like seen on the previous 4004. Seeing how these VCR are prone to problems with tentalums on the 15 Volt line shorting out, I strongly suggest investigating into why this powersupply did not shut down the 15V rail on overload properly, unless you want to fit a fuse in the 22,6V rail to make up for that protection feature not working. Side note; Why didn't you use a current limited(!!!) bench powersupply to externally feed the 15V rail? You could have easily seen how much current was drawn and which module was the culprit.
I am concerned about fake UA723 chips and will buy some from a reputable supplier, so could replace that later. The smoke was certainly a bad thing and I would want to avoid that risk again. I will be working on the machine again very soon: I'm fairly sure that the failure to operate deck functions is caused by another tantalum capacitor having failed. I'm not keep on using the bench power supply route, it could result in currents flowing where they should not since the machine's design may assume some 15V rails are only present when others are.