Hi Tony. Was gonna say when you popped open the covers on this unit, "a good ole stick of dyno might have been a better choice to this repair". You are a real trooper to this type of repair and vintage gear.

I appreciate your videos. I'm not a tech, but I still feel as though I learn a lot about craftsmanship and process as I watch how you systematically work through to a solution. I own a Pioneer SA-9100 (aka, one half of "the old married couple") so I was especially interested in those videos. Mine goes into circuit protection once in awhile, and three different technicians have failed to find the problem, so I appreciate the skill you showed in identifying the problem yours was having.

I hear you, no profit, just a labor of love knowing you did the repair the right way and you get the satisfaction of bringing back the old girls back to life... :)

This P.S upgrade board looks like Rick's (RCS16). What a Legend Rick is ! I have tremendous respect and admiration for the man who made this important upgrade possible. Not taking anything away from you Anthony, you too are a Legend for the amazing restorations you've provided for our benefit. i love watching your videos. Keep up the great work !

I love your work in how thorough and complete you are in restoring and upgrading these electronic components. I have a Pioneer sx- 1280 receiver that is in good condition. I would love to send it to you to upgrade any and all components in this receiver so I can enjoy listening to it for the next 20 + years without having any kind of problems or failures. I truly appreciate your expertise in this field.

That looks like a very nice set-up, Can't wait to see it done. Awesome job.Thanks for all the great work.

Great work Tony. I did a similar upgrade to the power supply of my Drake L7 linear Amplifier years ago. I got a specifically made kit for it. Was good fun. Love your videos. Keep them coming as often as you can. Warm regards from the Emerald Isle

I've had this video in my que for awhile. I have 2, sx1980's I just did a full restore with the new power supply on one of them and used your video several times. The new power supply now comes with the new protection chip installed as well as the big resistor. Nothing has to be added from old board. And he gives the some solder on ends for your wires, so you can just cut them off at the wire wrap if you want. The other sx 1980 will get the current source mod instead of the new board. But the new boards are certainly a work of art. Thank you for the outstanding video.

I have been a construction manager for many years andwe get the boxes with electronic controls etc, but never got involved in the detail of the units, so I got interested in speakers and controls which led me to tuners and amplifiers...... eventually to this field of restoration, I am very interested and yes learned a lot and indeed amazing and interesting, so I coming to the pint to maybe venture into doing some simple thing like cross over for speakers...so I enjoy and have absorbed a lot of information and be educated at the same time...I very much enjoy this sort of informative approach as how electronics work etc... very well thought out and explained even for a novice in this field.....which I am...

@johnvanvliet2076

4 жыл бұрын

by the way I build a set of speakers and they turned out really well.

Great job Tony! Made for good entertainment this evening. Thanks!

This video really reminds me of my 70s / 80s Heathkit builds. Nostalgia...

great video and thanks for explaining so clearly,.,.

This is absolutely awesome info on this amp. I may try this on my sx1980. Looking forward to the next video.

Another fascinating video kept me interested right up to the end Mike

Didn’t ask my daughter.... Nice knowing you Tony.

Hey Tony Great Content! looking forward to the next one!

Absolutely awesome watch thanks so much, the PSU build is the best 😍

Nice work Tony, thanks! Looks to me like you got a lot done. That green paper looks good on video!

Nice description and explanation of the soft start circuit. I've never seen it done like that. Quite clever.

VERY GOOD INFO! Thank you!!!

Really amazing vid, you are so right its not all about profit, I help others because I can and not for how much l can extort from them. My reward is to see tneir reaction when something is fixed that they thought was unfixable. Thanks for sharing.

Bravo pour ce travail, good job .

Gran trabajo está haciendo usted con este equipo, usted es lo más grande reparando estas joyas 👏👏👏

Always build up a board from all the smallest profiles first; it makes the mass soldering much easier.. Learned that when I was like 12.

I love phoenix connectors i use them for everything they are used exclusively in heavy industrial equipment . Ive never had an issue with one. I like that supply board thats the same one i have in my 1980 been there a while and works like a champ. Great video Tony

@wirenutt57

5 жыл бұрын

I concur with Apollo Robb, I'm an industrial electrician, and these connectors are used in all kinds of industrial equipment that get put in place in a hostile environment, with heat, vibration, dirt, dust, chemicals, and fluids, and if installed properly, never fail. Anyone who whines about them in a stereo receiver that will sit in a living room or media room in a home with temperature and humidity control is the kind of person who will whine about something just for the sake of whining. The also do it to make themselves appear knowledgeable, when it's obvious to a professional like myself and apollo robb (and Tony!) they are not.

@dhpbear2

5 жыл бұрын

And the converse, do NOT use MOLEX connectors!. The absolute WORST application I've seen was in the SouthWest Technical Products' 6800 computer (from the 'Altair Era'). They were employed as backplane connectors, carrying digital data, address lines and control signals between boards! YIKES!

Man oh man, I *SO WANT* a 1980.

I've been told to never slowly bring up solid state electronics with ICs and such on a variac because it will/can ruin them. Are you concerned with the IC on the power amp board? Or... is the "brown out" or "voltage starving" theory not true?

You really should do a video on restoring my 1250.

Great vid,,,, and yes the farrell work great with those terminals just need to make sure you are using the green and not the blue ones,

Regarding those big resistors that get hot so it's a hole in the PCB to let air vent trough, it's also important to remember that the leads of these components needs to be bent on top of the PCB so they'rr not only hanging in there by the soldering. So that when they get hot and the solder starts to liquify, the component falls out. That would be a bad thing to have happend during heavy use of the amplifier! Wonderful job so far, looking forward to the rest, and finnished kit.

43:46 - I'm guessing those two separate grounds should be 'starred' in the final assembly?

Another impressive video and restoration. I share and appreciate the way you take care of these machines. The way you choose the components is important, as it says you're not concerned about pseudo commercial discutions but top of the quality industrial solutions. I also have defended the use of these wiring connections and ferrules, as they are standard industrial solutions here in Europe for many systems from heavy equipment machinery to security systems, and they generally appear near perfect. Of course, you can eventually find faulty ones, particularly when solders are at stake with high stress and extreme temperatures, but there is generally not the case in these amplifiers. No need there of what we call ''nuclear and space" quality level connectors (Souriau, Amphenol...) Why use a 150$ connector instead of a 1$ one, that's always far better than wrapped connections. I also use marking rings for complex schemes. I applause to the replacement of the power supply board, that's efficient, responsive and is a real quality update for what you want to achieve in quality level. The fact you replace most components, and not only electrolytics, prooves you're about better and long lasting results. Anyway, some "audiophiles" can still reject this approach as they sometimes prefers the original sound "with defaults", wich is not in the original design I suppose. These always ask for minimal restoration or impossible replacement of long time obsolete germanium or flying saucers Japanese transistors. I appreciate the fact you prefer better and at least equivalent replacement solutions. In these Japanese machines, I must admit it's not always a simple equivalent table that tells you what can replace what (there are so many solutions to get a voltage reference, the two transistors and leds trick is good, but some modern IC can also do the job...).

To paraphrase EEVblog: "Don't plug it in - take it A-PAHT!"

Thats a boatload of old components and voltages. Time for a re-design. I use those type of screw terminal blocks all the time for my audio builds. The work great if you use proper gauge wire (for the size of the block), make sure the wire sits inside the blades properly and you don't overtighten. They never come loose !

Just off the top of my head, this outlandish, OCD-laden restoration would run around $4,000 USD. Was the original owner of this receiver Mary Todd Lincoln, who went through the Tardis? This whole time I've been like, "Are you f***-ing sh*tting me?" Unreal. The owner of this SX-1980 must be very rich and very eccentric. As for xraytonyb, this guy is a beast. Five out of five stars * * * * * .

Hey Tony love all your videos! would you recomend this upgrade for a SX1280?

Wouldn't a resistor's 'voltage value' derive directly from its power rating? (22:56)

@xraytonyb

5 жыл бұрын

Not totally. The resistor's wattage rating is the product of voltage and current. If you exceed the rated voltage of the resistor, it could damage the resistor by flashing over. It's really important when you are replacing resistors in tube gear because of the high voltages.

@dhpbear2

5 жыл бұрын

@@xraytonyb Wow. Flashing over! Haven't heard that term in years! Yeah, very high voltage is a whole different animal!

I assume that's chronological order by height.

Would you ever consider restoring a Pioneer RT707 Reel to Reel deck? I’d love to see a video of you restoring my deck!

Ferrule connectors and crimps (and all their clones) is all you need to clean up those terminal connections.

The Saturn V rocket of stereo receivers.

One thing ive understood, is that with the power supply being UNDER the transformer, that the heat may contribute to transformer failure. The holes in the board seem to dissipate heat well for the board, but doesnt this add heat to the bottom of the transformer? Perbaps a shield under the transformer is in order, or what ive read on AK about the heat to xformer relation is not valid. Good stuff, rhank you for your time. Ive followed your link and signed up with patreon

Well Done Have Sent You Some $$$ For Helping me out on prob again THX A Lott

Guys The Medical equipment that xraytonyb works on costs in excess of 1-10 million dollars US, I think that it would be better to use a PWM output stage which requires less current and voltage than the 80V specified rather than try to build a high voltage high power amplifier. I think that Vero Corp made a wire wrap tool.

Great work that new power board is very nice. So how much time did it take to figure out the those two wires not being needed?

@xraytonyb

5 жыл бұрын

Only took about ten minutes of comparing the schematics. Now, when we talk about that ground connection.....no comment! ;) Thanks for watching!

Replacing an old, poorly-designed power supply board with a modern alternative only makes sense if you're actually going to listen to the component. Not something to do if you want to end up with a museum-quality restoration, but ABSOLUTELY something you want to do if you're going to take this baby out as a daily driver! Myself, I'd much rather lose a bit of (bad) history in exchange for keeping beautiful, high-quality equipment like this in use. I think the original designer would be proud of you! *edit* Whoops! You said pretty much the same thing in episode 4 of this series. Great minds think alike, I suppose. ;-)

Those 1.2K resistors could have different TCR ratings, given the operating environment.

(@50:05) - I think I spy... a problem on the schematic. If you look, there’s a +80, +34, and +30 volt output, and the section below it has the corresponding negative voltages; -30, -34,and -80. The bottom section has a resistor between to -34 volt line and the -30 volt line, but... if you look at the top section, the schematic shows a dead short between the +30 and +34 volt lines - Oops! 😬

@xraytonyb

5 жыл бұрын

I agree about these schematics. They leave much to be desired. I think the designer or this board originally designed it for his own unit and then realized that there was a genuine need for this product by others. I truly appreciate the fact that he was willing to make this available to the rest of us. When I complete this project, I will contact him and share some of these findings so that we can make it even better for others who might want to do this upgrade as well. Thanks for the comment!

What size of wire ferrules did you use? Brand?

First of all I want to mention, that I am a great fan of your channel and the way you restore vintage stuff. But with the replacement of the powersupply of the Pioneer I cannot agree, because I thing one is corrupting the integrity of the original design. In other words it's not a Pioneer anymore even when it's better now. To me it's like restoring a van Gogh painting with modern paint from the supermarket. The colors are brighter, it's looking better, but is not a van Gogh anymore. The powersupply did function for perhaps over 30 years, why not restore it in a way it will for an other 30 years by using the old PCB and layout. I am sure you can do that, because you are really good. An admirer: Adri Kes from the Netherlands

@trickyrat483

5 жыл бұрын

Well, the honest truth is their are many ways to "restore" something. Sticking with the exact original specs/parts is sometimes impractical or undesirable. In this case, the owner of the device was keen to go this particular route, so that's what Tony is doing. Another owner may have felt completely different. Either way, each approach is the prerogative of the owner and perfectly valid.

@Dangrdav

5 жыл бұрын

Because of the original bad design of the power supply you are taking a chance of blowing either transformer or the output transistors. These are basically unobtainium parts. I agree it changes the original thought but unlike paintings technical items come out with service bulletins on changing the original design because it was not well thought out. Tony fixed the grounding issues on a au-x1 amp. It was a huge issue for the amp but now it’s ready for another 30 years.

@jansen2810

5 жыл бұрын

@@Dangrdav I see your point, but try to see mine. Pioneer must have had confidence in the design of the powersupply, because they did not alter it - as far as I know - justified, because it functioned for over 30 years with a small repair. Furthermore Tony took a certain risk of blowing up 'unobtainebles', because a mistake is easily made as it was a rather complex operation, the PCB could be faulty etc. Why repair something when it is not broken? Sturdier components would have done the trick also. Usually Tony just does that. Why did he use the new PCB? My opinion: the opportunity was there and most of all it is fun and makes brilliant video. And I am totally fine with that! Love to see the next one.

@xraytonyb

5 жыл бұрын

Hi Adri, In some ways, I totally agree with you. As a person that repairs /restores these for myself and others, I always have to look at the whole situation. I am always fascinated by the designs of these old pieces of technology. You can often tell this by the amount of time I spend going off subject and talking about them in my videos (much to some people's annoyance!). I really enjoy trying to find out what the designers of these units were thinking and trying to achieve when they designed them. These engineers were brilliant and they did amazing things with the technology they had available at the time. When beginning a new project, my first question is, "What is the owners motivation for this item?" A piece that has been well cared for and kept in the original box is a piece of history and an example of time gone by. In these cases, I might just clean and align the unit and leave it as a piece of history. Other equipment hasn't survived the years as well and will need repaired, quite often with parts that are no longer available. At that point it will either be a "shelf queen" or we will need to repair it with substitute parts that are still available. In this case, we still want to maintain the character of the unit while making it safe to operate. Last, we often learn more about things over time. While engineers of the past did amazing things with what was available at the time, there still were problems that had they know about at the time, they would have done something slightly different. If you watch the video series on the Sansui AU-X1, you will find out that there were some pretty significant problems in the original design that even the original engineers recognized and tried to repair in later models. The signal switching relays and the oscillation issues often prevented these incredible amplifiers from preforming as they were intended. By making some changes to the relays, some of the capacitors and the grounding layout, these can be made to perform flawlessly, as intended. This particular SX-1980 falls somewhere in the middle. It had some severe damage due to neglect and being stored in a damp environment. The power supply board provided the perfect voltages for the circuit, but they are well known to fail in their current design, due to some under-rated components. The new board uses almost all the same parts as the original, with only the high-failure parts being replaced by more reliable ones. The output voltages are identical and the amp will perform flawlessly without having to fear for something overheating or shorting out. That was my train of thought for this project. I hope people take the time to read this response, because your question was a really good one. Thanks!

@jansen2810

5 жыл бұрын

xraytonyb Thanks for your extensive reply. Looking forward to your next video.

What's the Mouser part number for those dual green terminal blocks?

@xraytonyb

5 жыл бұрын

2 pole - 571-282844-2 3 pole - 571-282844-3

@Wizardofgosz

5 жыл бұрын

@@xraytonyb Thank you sir! I was trying to find that very part by kind of randomly searching on their database but couldn't find that one. I ended up finding some terminal blocks that were a little bigger and ended up using those on a vacuum tube preamp build that I did recently. They were a little bigger than I needed but they still worked okay, but I think he designed the PCB for those slightly smaller ones.

My wife would say doing it for free that time you could be helping me I would say that's why I'm in the basement LoL

You look like you know what you're doing. How do I get in contact with you? I have a Marantz 2385 it still plays I would like to have it going over.

So you are a Biomedical Tech? Where did you go to school? I started in the USAF at the Biomedical Tech School at Sheppard AFB in 1975.

@xraytonyb

4 жыл бұрын

Great question! I'm actually not a biomed tech. My degree is in electronics (Penn State). I started directly in the Medical Imaging field in 1988. I attended my first x-ray school in 1989 and have been in endless training ever since. Several of my employees started out as Biomed Technicians and crossed over into imaging and others started out as electrical engineers. One of our techs also started out as a computer technician and he does a lot of the digital imaging/PACS services. One of my friends owns a biomedical service company and I leave all the anesthesia, ventilators and other biomed equipment to him, as he is certainly the expert in those fields (me, not so much)! . Thanks for watching!

What's the name of the company in Canada that made the new board for you

I like it but it's abracadabra for me.

Where are you located?

I don’t get how ten people could possibly did spike what thus guy is doing

Would you care to build me a set of the led current source?

Why not use a NTC for inrush protection rather than a fixed resistor?

@xraytonyb

5 жыл бұрын

The NTC device remains in the circuit and changes value as it heats up. The fixed resistor only needs to dampen the inrush for a split second, after which it is shorted out by a set of relay contacts to allow full current to pass from the AC mains to the power supply. The NTC device would just slow this process down unnecessarily, which would add time to the delay of the relay pulling in. Thanks for the comment!

The PS main output is +-76 not 80. That's a 5% drop. I my world thats a significant drop. That will affect the dynamic range of the amplifier.

@xraytonyb

5 жыл бұрын

Sorry about the confusion. I think I mentioned this in the video, but when I took those measurements, the unit was plugged into the dim bulb tester which was limiting the current and reducing the voltage slightly. As it was a first test, I didn't want to let it "off the leash" yet. Even so, those +/- 80V sources are just that, voltage sources. They are limited to only a couple hundred milliamps and are used for the voltage amplification stages in the amp. The main power for the output section is provided by a very large unregulated power supply that is not on this board. Those supplies consist of individual transformer windings for each channel, large rectifying diodes and four very large 22,000uF 100 volt capacitors. Those will affect dynamic headroom much more than the small supplies on this board. They were not connected yet in this video, but hopefully, you will be able to see them in the next part. One last thing, the main unregulated supplies will usually be designed to provide a bit more voltage than the output circuit requires for full rated output. This allows the output section to achieve maximum "swing" without actually hitting the top of the rail voltage. Thanks for watching!

@johnnytoobad7785

5 жыл бұрын

@@xraytonyb Ooops...my bad. Lots of stuf on that PS to pay attention to. I'm a bit paranoid since I built a class-D power amp last year (from one of those external modules). Those modules have a very tight tolerance for supply voltage. If it wants 60 volts, and you give it only 55 (from the caps) the amp module will not turn on.

Why not just through hole the wires and solder; no need for the old square profile standoffs/wire wrap crap...

@Discretesignals

5 жыл бұрын

It makes it easier for servicing and testing.