Pioneer SX-1250 Keeps blowing speakers right channel, Ideas Help?

https://www.ebay.com/itm/362267536415?ul_noapp=true

I bought this kit to install. What do you think?
https://www.ebay.com/itm/362267536415?ul_noapp=true

I bought this kit to install. What do you think?
Is there a list of what you get? I don't see any resistors, diodes, or transistors in there? Maybe there is but need a list to confirm.
Part of the issue with these amps is the capacitor degradation, but just as important is the BJT's that also cause issues, such as random popping, sizzling and various other issues.

I do not agree with the choice of some of the caps.
The Nichicon FG (Fine Gold) are not what I would choose for power supply applications, especially where they have you fit two radial caps in place of the axial caps, thats just bad workmanship and poor cap choice. There are so many parts of this amp which run so hot, and to slip some 85˚C Audio Grade caps in those places is not a good choice in my opinion.

They should be supplying Nichicon VX Axial caps in that instance, which are 85˚C rated, but those caps are not in a toasty area.

Nichicon PW Radial for the rest of the power supply.

Then depending on personal preference you can use for audio path.
Nichicon KZ
Nichicon KT (My preference)
Nichicon FG
and for low value you could use WIMA MKS film caps

Oh, and I only see one relay there too, I always replace the soft start relays as they get a hard time through their life.
So there should be two relays. I assume the one they supply is the speaker relay.

This is the path taken here in this forum, and there are countless SX1250 threads to follow along and make good choices from.

What I would do is when that kit turns up, make a list here of what you've got and we can help you add a few more items to it so you're on the right track to make your SX1250 reliable for years to come.
 
If the amplifier has had a hard life, I would be checking all the emitter resistors. I notice these Pioneer SX poweramps love to take out emitters when run hard, or have had an output transistor failure.
This would be a good start.
**^^^^**. This!
Edit: I see Kevzep is on this,
If you want to fix this amp, this is your guy to help you.....
 
This is the paperwork and parts list I got with box of parts.
Please feel free to recommend anything else or less than good results with parts I have listed here.
 

Attachments

  • MPSA92-D.PDF
    104.8 KB · Views: 12
  • Pioneer SX-1250_1 (2).pdf
    55.2 KB · Views: 7
  • Pioneer SX-1250_2.pdf
    56.8 KB · Views: 6
  • SX 1050 and 1250 tone amp.pdf
    54.9 KB · Views: 2
  • SX1250tips.pdf
    80.8 KB · Views: 5
Is there a list of what you get? I don't see any resistors, diodes, or transistors in there? Maybe there is but need a list to confirm.
Part of the issue with these amps is the capacitor degradation, but just as important is the BJT's that also cause issues, such as random popping, sizzling and various other issues.

I do not agree with the choice of some of the caps.
The Nichicon FG (Fine Gold) are not what I would choose for power supply applications, especially where they have you fit two radial caps in place of the axial caps, thats just bad workmanship and poor cap choice. There are so many parts of this amp which run so hot, and to slip some 85˚C Audio Grade caps in those places is not a good choice in my opinion.

They should be supplying Nichicon VX Axial caps in that instance, which are 85˚C rated, but those caps are not in a toasty area.

Nichicon PW Radial for the rest of the power supply.

Then depending on personal preference you can use for audio path.
Nichicon KZ
Nichicon KT (My preference)
Nichicon FG
and for low value you could use WIMA MKS film caps

Oh, and I only see one relay there too, I always replace the soft start relays as they get a hard time through their life.
So there should be two relays. I assume the one they supply is the speaker relay.

This is the path taken here in this forum, and there are countless SX1250 threads to follow along and make good choices from.

What I would do is when that kit turns up, make a list here of what you've got and we can help you add a few more items to it so you're on the right track to make your SX1250 reliable for years to come.
Hi I posted the lists of parts he sent, take a look.
 
When you take the top "grill" off, do you see the diodes screwed down to the heat sinks?
Bob
 
no mention of brands of parts apart from mpsa92 which i am unsure about in this application . i remember them being low on hfe gain .
 
no mention of brands of parts apart from mpsa92 which i am unsure about in this application . i remember them being low on hfe gain .

no mention of brands of parts apart from mpsa92 which i am unsure about in this application . i remember them being low on hfe gain .
I see,
Nippon Chemi-Con the 4 large caps
nichicon for most the other black and gold caps
OMRON relay

I cant really see the transistor brand name
 
Is there a list of what you get? I don't see any resistors, diodes, or transistors in there? Maybe there is but need a list to confirm.
Part of the issue with these amps is the capacitor degradation, but just as important is the BJT's that also cause issues, such as random popping, sizzling and various other issues.

I do not agree with the choice of some of the caps.
The Nichicon FG (Fine Gold) are not what I would choose for power supply applications, especially where they have you fit two radial caps in place of the axial caps, thats just bad workmanship and poor cap choice. There are so many parts of this amp which run so hot, and to slip some 85˚C Audio Grade caps in those places is not a good choice in my opinion.

They should be supplying Nichicon VX Axial caps in that instance, which are 85˚C rated, but those caps are not in a toasty area.

Nichicon PW Radial for the rest of the power supply.

Then depending on personal preference you can use for audio path.
Nichicon KZ
Nichicon KT (My preference)
Nichicon FG
and for low value you could use WIMA MKS film caps

Oh, and I only see one relay there too, I always replace the soft start relays as they get a hard time through their life.
So there should be two relays. I assume the one they supply is the speaker relay.

This is the path taken here in this forum, and there are countless SX1250 threads to follow along and make good choices from.

What I would do is when that kit turns up, make a list here of what you've got and we can help you add a few more items to it so you're on the right track to make your SX1250 reliable for years to come.
The Nichicon are rated for 85 C
 
The Nippon Chemicon's they are using for the main caps are okay, I used those.

Yes, the Nichicon's they have used are all 85˚C caps, which is not the end of the world but would have more durability if they used the higher temp grade and used caps designed for the application. Fine Gold are audio caps for example, not something I use in power supplies although they will still work.

There are better transistors out there to use than the MPSA, they are an old Motorola transistor which seem to be getting phased out, so many better options now.
They will be an Onsemi device now as Motorola was bought by Onsemi.

They have supplied some Nichicon KT Audio caps, and they are good caps, I use them in the signal path
 
Is there a list of what you get? I don't see any resistors, diodes, or transistors in there? Maybe there is but need a list to confirm.
Part of the issue with these amps is the capacitor degradation, but just as important is the BJT's that also cause issues, such as random popping, sizzling and various other issues.

I do not agree with the choice of some of the caps.
The Nichicon FG (Fine Gold) are not what I would choose for power supply applications, especially where they have you fit two radial caps in place of the axial caps, thats just bad workmanship and poor cap choice. There are so many parts of this amp which run so hot, and to slip some 85˚C Audio Grade caps in those places is not a good choice in my opinion.

They should be supplying Nichicon VX Axial caps in that instance, which are 85˚C rated, but those caps are not in a toasty area.

Nichicon PW Radial for the rest of the power supply.

Then depending on personal preference you can use for audio path.
Nichicon KZ
Nichicon KT (My preference)
Nichicon FG
and for low value you could use WIMA MKS film caps

Oh, and I only see one relay there too, I always replace the soft start relays as they get a hard time through their life.
So there should be two relays. I assume the one they supply is the speaker relay.

This is the path taken here in this forum, and there are countless SX1250 threads to follow along and make good choices from.

What I would do is when that kit turns up, make a list here of what you've got and we can help you add a few more items to it so you're on the right track to make your SX1250 reliable for years to come.
I posted pics of the kit in post #51
 
Look, its not a total disaster, just not quite what I would use, and as far as the TO220 transistors they have decided on, well, they aren't quite right either.

I am a bit busy right now, but I'll take a close look and maybe you can just do a small order from mouser and get exactly what you need.
 
The Nippon Chemicon's they are using for the main caps are okay, I used those.

Yes, the Nichicon's they have used are all 85˚C caps, which is not the end of the world but would have more durability if they used the higher temp grade and used caps designed for the application. Fine Gold are audio caps for example, not something I use in power supplies although they will still work.

There are better transistors out there to use than the MPSA, they are an old Motorola transistor which seem to be getting phased out, so many better options now.
They will be an Onsemi device now as Motorola was bought by Onsemi.

They have supplied some Nichicon KT Audio caps, and they are good caps, I use them in the signal path

So would I be ok if I went ahead with what you see?
 
Look, its not a total disaster, just not quite what I would use, and as far as the TO220 transistors they have decided on, well, they aren't quite right either.

I am a bit busy right now, but I'll take a close look and maybe you can just do a small order from mouser and get exactly what you need.

That sounds really great and many thanks,
Mike
 
There are 2 horseshoe shaped black what appear to be diodes marked 76A, one ea screwed on top center of each heat sink.
I will only tell you this once!!! CAUTION CAUTION CAUTION!!!!

These are STV3 diodes. They are very very difficult to obtain these days as they have not been manufactured for a good many years.
You must unscrew those, and whatever you do, do NOT grab them and move them around the place, be very very careful, hold them by the legs near the circuit board to move them out of the way, do not bend them by holding the diode, they will break off.
If you are unlucky enough to have one that is broken and have not noticed, the amplifier will destroy itself, blown output transistors, burned out emitter resistors....you do not want to go there!!

Extreme caution required!!
 
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