Pioneer SA-9100 rebuild

dukeofurl

Active Member
After having a TX-8100 tuner sitting around I decided to locate a amplifier to go with her. - I ended up with a SA-9100 but she needs some lovin'.

It fires up, no protection problems (phew!) and works for awhile then develops the crackling pop of hell (in one channel).

Yeah, she's old and needs to get a full recap job and transistors.
So, before I get started, I want to run through a few things.

1. Should I just replace the transistors before doing anything else to see if the "crackling" issue is resolved?
2. While ordering the parts; how many of each type of transistor should I get for matching?
3. Any words of wisdom on what areas to recap in order?

Think that's it for now, mainly want to get my shopping list in order and wait for the postman to deliver. :)

Thanks for any/all help!! :)
 
It's probably a cold solder joint that rears its ugly head once the amp warms up. I'd give the power supply board and others a good look at and re-flow some solder on them. This might just solve your issues.
 
Dis-assembly of these to get at the parts to replace them isn't really that much fun. If you're going in, I'd recommend checking the other Sa-9100 threads here and verifying the parts list before you do anything and going at the whole re-build. Mark the Fixer has been incredibly giving of his time and knowledge about rebuilding these and there are very valuable threads to prove it.

Just getting at these boards to pull and replace caps is something you'll want to do once and only once; solid-core wire will only take so much flexing and can be prone to breaking inside the insulation- a potential troubleshooting nightmare if it happens.
 
Thanks gents for your input.

I've opened up the amp and did the usual deoxit job and put the ipod into the MAIN amp input for about 2 hours. Ran perfect. :)
I am now running ipod into the aux 1 then PRE OUT to another amp. So far so good. (keep fingers crossed).

Only thing that I've had to replace, so far, is the "ON" indicator lamp.

Is it usual for the "MUTING" switch (-20db) to give out a pop when ingaged?

Yeah, not really in a hurry to start re-capping for the sake of it but wondering if there's anything that "should" be done to prevent future hardship?
 
Ahhh, the sound of crickets abound.

Well, Maybe I can make a move on checking the bias.
Any comments or tips? - The service manual seems a little vague on the subject. I don't want to move forward until somebody chirps in on the procedure.

Thanks. :)
 
Okay, we'll have to get back to the bias thing much later.....
I am very glad that I was having a VERY good look around the boards today!

Look at what I've found on one of the the (left side) power amp boards!

SO.... back to my original plan... buy all of the parts from mouser so they are on hand if/when required for this beast.
There are patches of rust around this amp. - Must've been stored in a cold, damp place. :(
While I've been deterred to do anything to this amp, it now looks as a MUST DO while I'll have to remove the board(s) for repair.

Can somebody give me an idea on the quanities of transistors to get for hfe matching? I'd love to get my order placed so that I can move on with this next weekend.
 

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No crickets... Nice find on the rusted out leg. Going back to what I said earlier. With amps that are over 35 years old, you will definitely need to look closely and test diligently the voltages on all points accessible. This is not uncommon. Obviously flowing solder over this component wouldn't help:no::no:

Provide all the details of the part and others will be able to help with a suitable replacement. i.e. the component code off the schematic (and/or the part itself) the board it came off of (L/H Power Amp in this case), and any other info.

With that kind of damage found, I'd be willing to bet there are other gremlins that may not be easily seen on this amp causing issues.

Also, re-capping is not just "for the sake of it" on an amp this old. The electrolytics dry out with age, this is pretty much guaranteed.
 
Thanks for that, solutionroom, I know this would need to be done at some point and wasn't trying to ignore the fact. - Was hoping that I might get a little help on the shopping list, but I've done as much as possible to put one together and placed my order.
I'm surprised to not have found any information or tips on the best ways to get around the boards without totally dismantling the thing.
 
Well... my shopping list went to crap... Ordered over $100 worth of parts and still missed a few things.... HELP PLEASE!

Trying to get the parts together for the power amp board since this is my first step.
The parts that I am looking for are:

AWH-023 c2 0.47 25 cssa - 0.47 50 667-ECQ-V1H474JL3
AWH-023 c12 470 6 cea - 470 6.3 647-UPW0J471MPD
TO3 mica insulators for q10 & q11- 534-4636

The first one, Mouser requires a Minimum: 1000. (uh, that's a few more than I require!)

Anyways,... I've got some Pal money to use so, as much as I hate it, could some good soul shoot me a link or two from the bay so that I can get things moving?
 
Phew,.. been awhile but finally managed to gather components.
Question about Q8 and Q9 on the power amp board;
Do we use grease between the transistors and the heat sinks or just screw them on?
I ask since there didn't seem to be any indication of past grease on these.
Also, as the new replacements do not have the same pinouts as the originals, it looks like the heat sinks are going to be a few degrees off from the original placement. - Anybody have any tips on that situation (if you've already done one of these)?

oh, one more question, for now; what is the material-looking insulation called, found on the power transistor wires?
 
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Do we use grease between the transistors and the heat sinks or just screw them on?
Use new transistor thermal compound* between the transistor and the mica insulator and between the mica and the aluminum heatink.

* the plain jane white stuff, not the fancy artic silver crap..
 
Yes, use a little thermal compound on the transistors that are mounted to the small heatinks. Just a very thin film is all you need.
 
Cool, thanks avionic. Regarding Q8 & Q9 transistors, with the small heat sinks; how did (anyone?) deal with the new pinouts (e,c,b) with the old layout of the where the heat sink sits onto the pcb?
 
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