Yard Sale SA-9500

nadude98

7MGTE Power!
Picked up a nice looking SA-9500 at a yard sale. Supposed to be overheating. Got it home and powered up with DBT. Relay clicked on so I tried to check and adjust DC. Left channel was fine and I got to the right channel and I can't do anything with it. Reading anywhere from 60mv to 600mvdc.

I then wanted to check pre-amp section and I get nothing but pops... cleaned controls to no effect.. sounds like I can hear something but faintly..
 
Its got the 2SA726's, 2SA725's and the 2cs1312's. Ouch!
The pre amp is influencing the amp with the bad transistors and causing the settings to become unstable.
Concur, get rid of the problematic transistors through out the amp.
 
q7, q8 are 2sc1451's in the power amps. it's listed as an alternative to the 2sc1628 in the BOM.

use ksc3503
 
Its got the 2SA726's, 2SA725's and the 2cs1312's. Ouch!
The pre amp is influencing the amp with the bad transistors and causing the settings to become unstable.
Concur, get rid of the problematic transistors through out the amp.

To make the adjustments the amp is operated in the separated mode. The preamp shouldn't still influence the amp should it?

several of the fuji transistors that need replacing in it
Fuji's?
 
If you can separate it. No influence.
Wonky preamp can play havoc on the amp.
You said popping when checking the pre.
Not sure what you are getting at.
 
If you can separate it. No influence.
Wonky preamp can play havoc on the amp.
You said popping when checking the pre.
Not sure what you are getting at.

I goofed! For some reason I was thinking that the headphone signal would be coming out of the preamp, not the amp... but it was popping with the amp in separated mode. Did some research and it looks like I should need 8 ksc3503's, 8ksc992's and 8 ksa992's...for starters.
 
Since you are ordering replacements for the known bad trannys, you should consider re-capping the power supply section.
Those caps usually sit next to or close to the hot power regulators, those caps tend to go first (dry out first).
 
If you are going to order/change bjts, might as well order/change ecaps as well, since you have it all apart.

I was just going through and seeing what transistor's I'll need. When I make a Mouser order I'll definitely get the caps. I was already looking at the SA 9500 BOM thread. I have sil-pads on hand so I will also put them in and get rid of the grease on the outputs.

This thing is missing the transistor covers, guess I'll have to shop for them too!
 
Just a note, on my board the caps listed below were actually 47uf 50v so I replaced the caps of the same value.

AWR-075: C20: 47uF 35v CEA: 647-UPW1V470MED 47uF 35v
AWR-075: C21: 47uF 35v CEA: 647-UPW1V470MED 47uF 35v

Also the below listed caps are tantalum on the board. So should I still replace them? If so what would be the best replacement to use? The one listed below or is there a better replacement option like WIMA film???
WS-082: C13: .22uF 35v CSZA: 667-ECQ-V1H224JL2 .22uF 50v
AWS-082: C14: .22uF 35v CSZA: 667-ECQ-V1H224JL2 .22uF 50v
AWS-082: C15: .22uF 35v CSZA: 667-ECQ-V1H224JL2 .22uF 50v
AWS-082: C16: .22uF 35v CSZA: 667-ECQ-V1H224JL2 .22uF 50v
AWS-082: C17: .1uF 35v CSZA: 667-ECQ-V1H104JL .1uF 50v
AWS-082: C18: .1uF 35v CSZA: 667-ECQ-V1H104JL .1uF 50v
AWS-082: C19: .1uF 35v CSZA: 667-ECQ-V1H104JL .1uF 50v
AWS-082: C20: .1uF 35v CSZA: 667-ECQ-V1H104JL .1uF 50v

One further note and question, on the Control Amp Board (AWG-032) the caps listed below were actually 100uf 10v. I was told before to make a parts list going by what is actually on the board.. so I replaced with caps of the same value. Just want to double check! Strange now that I look at the SM. On the schematic of the complete system they are shown as 100uf 10v yet on the individual board schematic they are shown as the 33uf 10v ones.

AWG-032: C7: 33uF 10v CEA: 647-UPW1C330MDD 33uF 16v
AWG-032: C8: 33uF 10v CEA: 647-UPW1C330MDD 33uF 16v
 
Last question 1st. Remember the manual was made BEFORE the actual production of the amps @ PIONEER. Line changes occurred that never made it to the drafting Dept. Go with what's on the ACTUAL board. Bump the voltage to 25v on the caps. Plus different people drew the schematic and the individual board drawings. They made a lot of mistake's.

2nd question. Your choice the ecq's may be slightly wider, and the Wima's slightly narrower than the pin distance. So make sure the pin distance is either right on or very close. IMO they sound the same, as my ears are bad, so YMMV.

47uf 50V is fine.
 
Last question 1st. Remember the manual was made BEFORE the actual production of the amps @ PIONEER. Line changes occurred that never made it to the drafting Dept. Go with what's on the ACTUAL board. Bump the voltage to 25v on the caps. Plus different people drew the schematic and the individual board drawings. They made a lot of mistake's.

2nd question. Your choice the ecq's may be slightly wider, and the Wima's slightly narrower than the pin distance. So make sure the pin distance is either right on or very close. IMO they sound the same, as my ears are bad, so YMMV.

47uf 50V is fine.

K, thanks
 
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