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SA8500 only works on DBT

In in Post #1 he specifically mentioned the AWS-083 (not -085).

But Pete is right in that they are in essence identical aside from some typical Pioneer device number "flexibility" among types.
 
Watthour said:
In in Post #1 he specifically mentioned the AWS-083 (not -085).

But Pete is right in that they are in essence identical aside from some typical Pioneer device number "flexibility" among types.
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True although he mentions AWS-085 in posts 23 and 35. It doesn't affect the recommendations in this case but it does add confusion. It would probably be useful for the OP to include his location so we know which board we should be looking at.
 
paultlaw said:
I'm sorry Pete, which boards
are we on here?
Q2 on awh 084 is 2sc945 and q1 is 2sc1621

Replaced the 945's with KSC2383YTA
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Was there a reason for replacing them? And if bad, why not use the KSC945...an EXACT match? I know that MTF has recommended NOT replacing the Qs in some Pioneer protection circuits unless they actually test bad due to the design of the circuits. And pioneer used the 2SA733 / 2SC945 combo in several of them. Since both are available as modern production, I'd use those... (KSA733 / KSC945).
 
.It would help to know exactly what is inked on each board, just for clarity.

In any event, Pete probably nailed it already. That regulator circuit is highly suspect.
 
I'm in Ireland, messed up on boards given the variations. sincere apologies im still green as hell.
So turns out I have the sa733 so I put them in, then put back in the 945 I replaced, q2 I believe. replaced d9 with a 1n5244b also.
Powers on dbt, then without relay kicked back in, you were on the money Pete.
Pin 17 of the power amp board is now 40v.

I ordered some 935c suffix and will replace all of these also, maybe that will sort the voltages out a bit better.

What's the best replacement for ksc1451 which I think are supposed to be trouble makers and actually should be replaced.

My sincere thanks to all of you, a few pints are owed. Possibly a siege of pints :beerchug:

Its not over yet, filter caps will be done, and ONLY trouble prone transistors I get from your recommendations.
If there are any that should be pulled, please do let me know
 
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it should be 35v .. a 13v zener should get it closer .. p.s it wasn't me that spotted it .i just pushed the issue
 
Just to add, this is being done for a true friend, no money involved only parts, just wanted to make sure the amp will outlive him! Then its all mine:D
 
cant edit quotes into my last post ...
LesE said:
You will also want to check the regulated power supply pins 34-39 on AWS-083. Your measurement of pin 17 on the power amp board is too high (52V which should be 35V). Q1 on AWS-083 may be shorted C-E.
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Will order for this board - AWS-085 B for GN Type - Page 55 and 56 of service manual.

1N5243B (13v) use instead at D9
MJE15032G will replace 2SC1626 at Q1
All the 945's and 733's will get the exact replacements as they are still available
 
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OK all changes above made, have 36v at pin 17.
Also changed d10, same as d9.

Edited as old 992 was missed for replacement, after got my parts order.

Are we back in business?
 
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