More videos like this with newer receivers and amplifiers please. Showing the problems on schematics is wonderful. Keep up the good work.

That was outstanding repair and maintenance, that piece of equipment will rock on another good years.

another 20 years that JVC will Good sound & nice to look at

Nice video! It's not often you see people put this much effort into these types of systems but fun to watch. Most of my gear is early 80's which has me quite familiar with the Sony Glue. I had to change out about 30 components from corrosion on my Yamaha A-1000.

Awesome repair Dave! This was a very interesting video to watch and learned quite a bit. You solved why my old unit failed, it had to been them bloody zener diodes as the power meter light did fail but I never bothered to replace the backlight as I didn't know much back then. That's probably all that was wrong with it. :/ Thanks again for your hard work and please let me know via e-mail what I owe you. :) I'm sorry it took you an entire day to service.

Excellent repair and tasks :-D i don't mind long repairs as i've also spent a lot of time on some items i've repaired. Some have been a bad mess and it takes ages to find every problem. I didn't expect the input switcher to make any difference, i've never seen an amplifier that didn't leak a tiny bit, the owner is worrying about nothing. You missed a chance dave, when it became a bonfire you didn't have a sausage on a stick to cook on the fire he he :-D

15:58 Thank You, i knew disc caps could potentially fail but you've just broken my disc-cap cherry. Never seen one short before now, or even be bad in any way aside from physical damage. Shame we can't use some tech like an X-ray microscope to see the failure mode, would have to guess it was the culmination of a defect from the factory, pore in the ceramic or similar.

Great job Dave! A light shining in from the opposite side of the circuit board will allow you to see the traces really well for troubleshooting

@12voltvids

5 жыл бұрын

That only works with single sided boards. Multi layer boards wont do much good, especially with shielded layers.

@Darryl603

5 жыл бұрын

@@12voltvids Was that a single sided board you were working on?

I always make sure my desoldering braid is 100% saturated with solder before tossing it, I've even been known to keep off-cuts if there is still a usable spot. And I agree with you on the desoldering pump thing, if its not new then it'll drop little flakes of solder onto the board. I learned that whilst swapping out caps on a densely populated TV SMPS.

@12voltvids

6 жыл бұрын

I have one of those solder suckers. I only use it big things like flyback transformers. I used to have an electric removal system but it packed it in many years ago and I don't do enough volume to warrant getting another one. Solder wick works good enough for what work I do as you saw.

14:27 Oh no! You've let the magic smoke out! :( If something like that happened to my equipment, I'd probably give up. Very interesting repair.

@rawr51919

6 жыл бұрын

_Something_ must've made the resistor go haywire... If Dave figured out the cap problem before he turned the receiver on, he could've prevented the smoke.

17:49 It works well!!! Thumbs up! Very interesting repair. Great video as always. :D

Always great instructor!

I've never ever seen a shorted small capacitor like that, nice find. Well this one .. a lot of screws but at least everything looks logically placed and a lot of room. Nice one again!

@12voltvids

6 жыл бұрын

Luc Peeters Yes easy to work on. Shorted ceramic cap. In HV circuits like horizontal output on TV sometimes they fail but never on low voltage stuff. Well not untill this one lol. That's why I missed it initially. Not looking for it untill there was flames.

@victorcoss2600

6 жыл бұрын

I don't think that cap failed on it's own, too much of a coincidence if it did. I really do think it was from moisture/water getting to that cap or around that area of the circuit. I've learnt my lesson and will use my brain next time! :P

good day sir.. i have db audio kvg umak1518 amplifier i has a burned recister also has a distortion sounds when it power of and tuned to fm or mp3 so after i opened the amp i saw burned recister left besides the 2 big capacitor after i replaced it it also smoked up and 1 other recister burned when i replaced it yes it powers on without any mess but no sounds.. what and where to test other parts may posible to be damaged?thank you

Any tips on how to problem solve power amps in protect mode? I have a Cloud 1000W amp, stupidly i touched across the two heatsinks and got a huge shock. Now it's always in protect mode!

I have a question. Please. When you tested the "Zener diodes", how did you know that the values (0.6 and 0.4) were "bad" or that it indicated a failed component. I am really dying to know. Thank you!!!

Wow good job Sir. Well done

Stupid question but,what was that guitar part in your video? What was the name of that song and / or band?

Enjoyed this very much.

good job dave as always

I have one of these and have always wondered what is meant by power level indicator. power level of what?

Thumbs up for your honesty and not hiding the smokey part. Nice repair, BTW.

@Poppinwheeeeellllllieeeeez

Жыл бұрын

The magic smoke from Dave the grand poobah of shotty work.

Thanks for your videos!

😲 wow learnt so much thx!!!

I have one I need fixed how much would it cost for me to send it to you for you fix it

hi thank you for your video very intrested and profesional i have a jvc went i power i have a message overload any idea what could be

How much do you charge to look at a unit? I have a JVC RX-715V that has a few issues.

Bonjour, j'ai le même modèle de receveur que vous réparez et il ne s'allume plus depuis hier sans raison apparente. Il n'y a eu aucune coupure de courant non plus. Avez-vous une idée par quoi cela pourrait être causé svp?

Where are you in Canada I need my bel canto pre2p fixed thanks

hi i am doing the same thing to my AKAI Gx77 LUCKY IT'S MY DECK i had to pull the deck a part to put new caps in as they did the reg's in alot were burned out a bio reel to reel that's been pip up for 15 ips is hard to get hold of

What headlamp magnifier you using?

Hi i have the same receiver but my output lights in the front dosent work. Any ideas why??

you let out that magic smoke but luckily you had spare smoke capsules :D

- Sony did use this shitty glue themselfs to. It can be found in many 80's components. The TA-AX series ampifiers had these problems. Maybe others to, I don't know. - You can also use tuner 600 spray for cleaning pots (only), it's less agressive and works well, and will expand the lifetime of these things. - Nice job on the repairs. Been subbed for only a few days now and enjoying your work!

To unplug solder pump tips i use the pull through wire that you find in flexible conduit. I guess it's galvanised. Seems to work.

We'll stick with our 70's and early 80's vintage receivers that we service and use. I've got an older Realistic STA-180 (made by Hitachi) that would blow that receiver into the next county.

Why does it seem every electrolytic I test seems to go up in capacity? is that normal? I.E. 47 uf will read in the 60's ... anything to do with ESR?

@12voltvids

5 жыл бұрын

Capacitor manufacturing is not an exact science. They will never measure what they are rated. Usually it is over. They can be as much as 10% under and 20% over and be in spec.

Idea for a video: Maybe make a video of what you ( in your experience ) is good spare parts to keep around since you do a lot of vintage to modern repairs of amps and tv's and such.

first Great project, beautiful video. as always

@12voltvids

6 жыл бұрын

Thanks. Yes I spent a bit of time on this one, in the end total success.

These thermal pads are specialy designed to transfer heat and isolate element from heatsink ... when you put thermal paste (or grease) you make it much worse and messy and heat dissipation is dramaticaly less than without thermal paste here ... beter alternative is to remove pads and leave only paste but only if transistors are in isolated package, otherwise this thermal pads are the best solution here but without paste ... if you need proove just mesure temperature with and without paste. On the other side, i love to see some old real electronics get fixed and granted with new life ... it makes me happy too

@victorcoss2600

6 жыл бұрын

It uses Toshiba 2SB1429 and 2SD2155, and the back of them look like a metal pad. Like this picture, www.picclickimg.com/d/l400/pict/121078066485_/2SB1429-Original-Pulled-Toshiba-Transistor-B1429.jpg Is this an isolated package? I get what you mean, you don't want to short the transistors out against the metal heatsink. If what you are saying is true, I hope Dave will revise this, given he hasn't already boxed the unit all up. As I don't want worst heat dissipation, I run these transistors pretty hard.

@victorcoss2600

6 жыл бұрын

After doing a little research myself, I shouldn't second guess Dave. It appears what he calls "insulators" are called mica and doing research on these "mica insulators" which they come in various sizes, several people on different forums state that you SHOULD put thermal compound/grease on both sides of the mica. This mica is supposed to keep the transistor from shorting to the heatsink. Most people say just a small pea on each side, some say to smear it. Everyone says don't add to much, as too much thermal compound is actually a bad thing. Dave was right..

@12voltvids

6 жыл бұрын

These transistors have a metal back electrically connected to the collector, and therefore require an insulator. The insulation material have a thermal compound in them. Adding a little more thermal compound, and this is not the run of the mill silicon grease that radio shack sold, will only fill any gaps between the metal back and the pad. The key is not not put too much on, just a thin coat which is what the insulators had on them from the factory. These are not thermal pads like you have on a CPU, they are very thin mica insulators coated with the same compound I used.

@victorcoss2600

6 жыл бұрын

Good stuff to know! These "micas" as I see they are called, weren't clear so that indicates they have thermal compound in them? As I see clear micas and people say USE THERMAL COMPOUND on them. I'll do my research first before jumping the gun and thinking there is a problem when there really isn't, one of my downfalls I am working on. Good work, and we have a lot to learn from you, that's why I love to pick your brain.

@12voltvids

6 жыл бұрын

Mica insulators are very poor at transferring heat. After all it was used as home insulation. Vermiculite is basically expanded mica. Thermal grease is required for the mica insulators. These ones are still mica based , but they have thermal compound between each layer so they do transfer heat quite well. The key is to not put on too much. Too much will result in less heat transfer. Just a thin film is all that is needed, and when the component is fastened, the paste spreads out to fill the air gap. I did not put a ton on the insulators, just enough to fill any air gaps between the metal heat sink and the transistor / insulators.

hello 12voltsvibes i have a quesation for you i got a pioneer 6 pack cd model pd-m40 and the lens fell out i put it back and its staying and working great but i was told to super glue it in back but am worried the gases from the can you tell what i should i trust you answer more then anybody else thank you

@12voltvids

6 жыл бұрын

Yes we used to super glue them in place at the shop. A tiny, tiny ammount is all that is needed. I used a toothpick. The smallest drop on the tooth pick, and then to the very edge of the lens where it fits into it's holder did the job. There are other glues that will also work and don't off gas such as good old white glue that kids use in school. Apply the same way. I used to use LocTite, you know the stuff used to keep screws from unscrewing. That worked great, and doesn't off gas like krazy glue does.

Sir can u help me to repair JVC MX-JD5 PLS

love your videos as you know what your doing and its great to see vintage gear back to life, . so i have a jvc ax 77 i got yesturday and is stuck in protection mode ,, im in england is there anyway i could send the amp to you to fix regurds danny

@Foozlebop

6 жыл бұрын

That's a very high end amp. Worth it! I'd watch that video any day.

Can someone explain to me how the computer controlled receiver works

sir can you explain what is negative and positive supply of dual power supply to preamp tone control and how to wire ty.

@12voltvids

5 жыл бұрын

Operational amplifiers or Op Amps require a split supply. The easiest way to generate this is with a center tapped transformer. The center tap is your ground, and one winding winding to the positive rectifier and the other to the negative.

What a kool JVC RX r76

@greggaieck4119

2 жыл бұрын

If that was my JVC receive that had a short coast to much to get fix i wood get a new recive

@greggaieck4119

2 жыл бұрын

I like the mucik you wore playing

The glue that holds large capacitors to the pcb as the years passing dries and is turning from white to black and from insulator is getting conductive.

Guess I should explain. Based on one of your videos, I bought a pioneer 700 disk player. Of course it worked but not when I got to me! Drawer doesn't open. Light blinks for a bit then the menu board goes to stop. So maybe you could fix it?

@12voltvids

6 жыл бұрын

Laserdisk?

I know it is a a slim chance of getting a response, but what are some reasons why the receiver won’t power on? The dual tape deck, and disc changer powers on, but not the tuner.

@12voltvids

2 жыл бұрын

Could be just about anything. You will need to do some inspecting . Check fuses ext.

i was realy expecting to see a old stk module in the power amp but i like this unit all transistor outputs its not that bad ....

@12voltvids

5 жыл бұрын

So does the guy that owns it who spent a small fortune on shipping it to me to repair. It's not a bad unit for an all in one receiver.

@t-rodshader9593

4 жыл бұрын

I honestly did too. But as well as i have seen a few that did not. Like this one. Surprising for a slightly low-end 90's receiver. But not all the STKs were bad. So of the Technics amps of the 80's-90's were decent and some superb sounding but would overheat some would and cause the SVI sereies pack to get so hot it would desolder. But some were decent at almost 30 pounds and well over 100 true watts. Not many of the 90s receivers were worth a single dime but there were a few. Probably less than half of them. But the SVI (computer driven stk) drove the fan and protection relay as well so it is crucial that they keep solder joints intact very well and that the fan stays clean.

Another one fixed. I use a towel or foam mat instead of tape, sometimes tape can peel the finish.

Awesome repair! a very extensive diagnostic on this one. It seldom for a ceramic capacitor to be shorted and this will give a headache when it does. I've learned a lot from your explanation why could this happen. I'm currently working on a Technics amp model SUV6X which is a dead unit and found lot of failed diodes, resistors and transistors and have them replaced. Right channel Power transistors were shorted and I have them replaced including the left transistors which are good btw. The only problem was a Germanium Diode -OA90 which is not available locally and I'm still looking for a replacement online. Can I use 1N60 diode as a replacement to this one? Thanks! more power to your channel!

@12voltvids

5 жыл бұрын

A silicon diode has a much higher forward voltage than a germanium diode. Look in an old AM transistor radio, they usually have germanium diodes. Germanium diodes have .2v forward voltage drop, whereas silicon .6v

@alcadzbetz

5 жыл бұрын

Hi Dave. Thank your for your response. I have an old radio here and I will check for that later. I appreciate your help. Thanks!

what r u wearing in ur eyes?

I like the video's for the jvc vintage receiver..would like to know your location..or so I can see what reason..for my two receivers..problems have..in great condition panel lights wont work..even new fuses..but still give out sound...thanks in advance

@12voltvids

5 жыл бұрын

I'm just outside of Vancouver BC

@dalemorgansr.8131

5 жыл бұрын

@@12voltvids address..so I can see how much cost to ship..i have 2 same model's different numbers..love these apmlifers..run them together..throughout 2 story house..😎🤘

I'm so mad at myself right now!!! My receiver was working perfectly. But I was worried about the D812 and D815 diodes. So unplugged it and went in to remove the two diodes so I wouldn't have problems in the future. I didn't have a long enough wire snips so I wiggled them out, I thought, very carefully by bending them back and forth. Now my cool LED display is not working at all. What did I do and how can I fix this. Sick about what I did 🤦

Gd day who can help me,I have my jvc ax 44 mdl.i lost the value of main power transistor,can u help me pls? Thank very much

What kind of transmitter are you using? Is it a kit or an assembled unit? I want to use one of those to send a signal to my antique radios. Thanks for your great videos.

@12voltvids

5 жыл бұрын

Both the FM and CQUAM am stereo transmitter were kits. I also have a little more player FM transmitter unit I bought for 10.00. Both the FM and am kit builds are on my channel. The am transmitter is over the top as it is am stereo. For vintage radios a mono transmitter is all you need. The nice thing about the one I built is it has auto modulation control so it sounds fantastic and will make any am radio sound as good as an am radio can sound. An am stereo radio sounds simply amazing.

@audiobuff77

5 жыл бұрын

@@12voltvids Thanks! I'll check out your video. There is a very simple breadboard AM transmitter setup available on the Science Buddies website, but I would like something a little more robust.

@12voltvids

5 жыл бұрын

@@audiobuff77 This one was relatively expensive. 130 I think but the sound quality rivals a broadcast transmitter on both mono and CQUAM receivers. I did a demo of the sound quality recorded through it into an am stereo radio. With the high power option 400mw it goes about a block with the built in antenna. More than enough to cover the house.

It's not working it's fully dead I wan to repair my self by ur help pls sir

Do (can) you use flux with solder wick?

@12voltvids

4 жыл бұрын

Yes and yes sometimes.

The JVC receive is kool

@greggaieck4119

2 жыл бұрын

Kool mucik

Their are a bunch of solder suckers ,I bought one for 7.95 ,works better than anything I have ever use ,I bought it on ebay ,it orange ,I would love to send you a picture of it ,I like it so much I bought another for a just in case ,mine ever fails but it hasn't ,it would be cheaper for you to buy one ,I could send you one ,but to canada ,it wouldnt be cheap .but it's a dam good investment ,I have tried everything else ,this works the best for most things ,

I only use that white thermal compound for making ICs easier to read. I would not use it on a CPU nor anything else I cared about. Arctic Silver is MUCH more effective. Top-hole vid as always.

@12voltvids

5 жыл бұрын

Who says I care about equipment. It's a machine after all. The since oxide silicone paste was good enough for the manufacture. It is good enough for me. I am not about to source expensive materials because I can't recover my costs from a client. I once ordered a 5.00 part and the shipper sent it fed ex instead of by post. That triggered a 37.50 broker charge that I was happy to pass on to the client which pissed him off with me. But had I not passed it off then I would have lost money on the repair and that is not sustainable. I'm in the business to make money not operate a charity.

magic smoke ...

Kool Micki

@greggaieck4119

2 жыл бұрын

I which I no how to fix radios

i didn't know you could put zener diodes in series

Epic fix

Awesome tune on 18:15, who's the artist btw? Thanks

@12voltvids

5 жыл бұрын

musicbakery.com/royalty-free-music/vacationers/

I'd keep that used solder wick for repairing bad traces and use some heat-shrink if needed.

Great vids. How do I get ahold of you?

@12voltvids

6 жыл бұрын

email volt@telus.net

I've got the same JVC unit and the same problem. Would you consider repairing mine?

@12voltvids

4 жыл бұрын

Sure why not

@markjuckett553

4 жыл бұрын

@@12voltvids Have you got a website or email I can reach you? Thanks again

@victorcoss2600

4 жыл бұрын

efir.io/en/youtube/12voltvids

Wow... This hours takin excellent work should be expensive for the owner.

@victorcoss2600

6 жыл бұрын

Going into it I told him I would pay him well and provide a tip. He wanted like $100 to fix the fault, I was like no way, I'll give you at least $300. I'm paying him what he's worth, even if I have to pay in increments, I don't mind. There was a reason I shipped it all the way to Canada... he knows what the hell he's doing and will go the extra mile.

@12voltvids

6 жыл бұрын

It wasn't as long as the time clock shows. I worked on it for awhile, then went and cut the grass, then took the Harley out and went for lunch, and dis some more work on this. So it seemed like an all day job, but it was more like a couple of hours.

Megafarads! I think you meant millifarads. Good video, thanks.

@12voltvids

6 жыл бұрын

yes I meant milifarads, one up from microfarads. I head it when editing and went DOH. Actually I thought I cut that! I must have forgot to hit the ripple delete key as I did mark that for deletion. That's what happens when editing at 1AM and trying to finish up so the render can happen over night.

I have a Sony XPeria Mobile Phone that worked fine until it just died on me. If I send it to you, can you try to repair it for me, please, as I would prefer an expert to look at it?

Hope he paid u well!! I charge btwn $20-120 depending on equip and repairs

@12voltvids

5 жыл бұрын

I did OK on this one. Shipping however cost a bundle. Over 200 to ship to me and back, plus the sender mistakenly declared a high value which triggered a crap load of taxes that shouldn't have been there had it been declared as non working / salvage.

22:40 "This unit is so old"............ umm... so does that make my 70's amps complete and total dinosaurs?

How may we send you a unit for repair

@12voltvids

Жыл бұрын

Contact me by email

I need one of these fixed

Wow! This must have cost a fortune!

@victorcoss2600

6 жыл бұрын

Not if you have a job and work hard for you money. I already told him my budget, he wouldn't of done all the OPTIONAL items on the checklist if it would of costed over my budget in time and labor costs.

90's rack system receiver.

@victorcoss2600

6 жыл бұрын

Stylistic GX-8740CDM to be exact, got it from newspaper/magazine archives.

As far as a circuit bulletin, just gut the old LCD/LED light bulb VU meter and replace it with a nice blue-green VFD ;-) But eh. thats just me.

@12voltvids

6 жыл бұрын

THEtechknight It's all about keeping a vintage receiver looking vintage. Yes I could have put a big resistor in there and some LEDs but again it is all about keeping things stock. My old beer signs that were lit with a 7w bulb could easily be fit with a 1w led but they don't have that warm glow so I stick with the 7 or 4 watt incandescent. For the number of hours they run it costs me nothing to run them.

@THEtechknight

6 жыл бұрын

Sure, but VFDs are vintage ;-) I dunno I just have a VFD fetish. everything has to have a VFD. :-P

@12voltvids

6 жыл бұрын

THEtechknight They might be vintage but they were not original on this unit.

@victorcoss2600

6 жыл бұрын

No, I like JVC's pick of their vintage orange and red, and I provided the fuse bulbs and they were very cheap to obtain. Though I have seen them use blue/green combo as well, but orange and red were their style and I dig it. The power meter itself are orange LEDs, the backlight is just an orange/red piece of transparent plastic paper like thing.

@THEtechknight

6 жыл бұрын

The JVC I owned was an orange color filtered based unit as well but it had a VFD behind it instead of LED or LCD., it was an AX-R450. The indicator was a spectrum analyzer instead of a VU meter. That thing was a powerhouse! I forget what it was rated for, but I had a pair of Technics SB-CR99 speakers hooked to it, and I could get it so loud that the woofers would start smoking. Anyways, at the end of the day all that matters is what you want and how you want it to be, and how you want to use it ;-) Oh, and that you enjoy it :-)

I love long video. 14:28 that would definitely bring me to panic

59:09 a repair checklist.. If he knew what to repair why did he not do it himself??

@12voltvids

4 жыл бұрын

These were things he wanted addressed.

Usually taxes are to 1)fund gov't 2)punish specific private sectors 3)change behavior. What is the reasoning for he gov't to tax incoming packages?

@BlodaBlodaBloda

2 жыл бұрын

Because they can.

@ranbymonkeys2384

2 жыл бұрын

@@BlodaBlodaBloda Gov't usually have some lame brain idea behind it, probably to get people to buy Canadian made products. The thing is that country really doesn't make good oranges and end up EDIT (hurting) the poorest among us, just like when they tax corporations they are taxing the consumer not the corporation. If they are taxed more the cost of the product just goes up but people can't seem to figure that out. Printing money works the same way.

Turns it on. Flame jumps up . . .'that's not good' . . . classic . . .

@12voltvids

4 жыл бұрын

Hehehehe

What a pain!!

From the sound of that distortion, my guess is that one of the power supply rails is hoopajooped.

@12voltvids

6 жыл бұрын

Yup, knew that going in. Thats why I went right to the power supply to check for a missing voltage.

*poof* and the magic smoke comes out!

The magic smoke. I'd pay $35 for that at a thrift store if it had the remote control.

Mildly heating up that circuit-glue will make for easier removal!

i got the same problem cept i get some sound [severely distorted] on channel 2 channel 1 works fine but after a while of having channel 1 hooked up and nothing plugged into ch.2 ch.2 side heats up plus i feel electric when i touch the heatsyncs kzread.info/dash/bejne/onp7x5Zun8vap7w.html i didnt violate anything playing that song lol youtube said 😀

That thing must have some sentimental value it amazes me how someone will spend money on basically junk it's not even remotely high end.

You can probably find that on EBAY for $ 80.00.

Smoke on the water and fire in you eyes.

gut jab maister

why the customer wanna keep this cheapo amp so bad?

@victorcoss2600

6 жыл бұрын

Cheapo? This was a $1,200 mid-tier rack outfit in it's hayday. We aren't talking about Sanyo or late 90s early '00s all in one bookshelf stereos here. I've had cheap... and this ain't it.. it's more mid-range. We ain't talking about mid 90s receivers either full of digital processing chips and other garbage to alter the analog signal going to the output stage. This is a full analog amp. And we sure as hell aren't talking modern receivers that only last a year or two, trust me I know several people that spent money on em and they all have problems. This thing lasted 30 years strong and only failed cuz I was stupid to wipe it down with a damp cloth and short out a capacitor. Now get lost!

@tacofortgens3471

Жыл бұрын

@@victorcoss2600 I dont believe that, Sanyo always kade cheap stuff. Same with Hitachi. You can see with the build quality it was all cheaply made.

@Poppinwheeeeellllllieeeeez

Жыл бұрын

@@victorcoss2600 that is heap of shit in a brown paper bag

Audiofool detected.

its no good hahahhah

No Sound just distortion, instead of fixing it you should have sold it to some guitarist and buy to owner a new one, lol.

@12voltvids

4 жыл бұрын

This was a customer's unit.

Great vid but why would the customer be assed with such a pile of shite receiver !!? I've pulled better out of the dumpster !

That unit. Is worth no more than $20.