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Pioneer sx950 powers up but no relay click

Anonky

Anonky

Kenwood KR-9600 / Pioneer SX-950 / Sony STR-GX10ES
The unit powers on with DBT. DBT has initial bright light then it dims significantly and barely is lit up thereafter. Powers on fine without DBT as well, but no relay click under either condition.

Power supply voltages at pin 1-15 without the DBT:
1: 0v
2: 5.2v
3: 5.2v
4: 13.3v
5: 13.3v
6: 49.7v
7: 49.7v
8: 0.1mV
9: 0.1mV
10: 0.1mV
11: 12mV
12: 0.1mV
13: -13.4v
14: -51.2v
15: -47.9v

Still somewhat new at this but the questionable readings to my untrained eye appear to be 8-10, 11, and 15. Which I would then next think to replace Q5-7. Is this rationale correct? I’ve read other threads where Q5 is commonly a problem. Not sure if these replacements alone will resolve my issue or is there a possibility of additional issues further upstream of these transistors? For what it’s worth all of the caps visually look fine. Next steps? Thanks in advance!
 
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when posting board readings, keep the reader's guessing to a minimum. Name the model, and the board # in the text close to the readings.
include the should be voltages, in parenthesis on the same line. saves time.

q7 depends upon q5 so q7 could be good

but doing Q5, Q6 & Q7 will get the power supply corrected.

Then we shall see if the protect is satisfied, or if there is more to do.

frankly I would do the protect, at least C1, C2, Q6, Q7, D8 + 1 more 1n4004 across pins 9 & 10 & various e-caps.
 
markthefixer said:
when posting board readings, keep the reader's guessing to a minimum. Name the model, and the board # in the text close to the readings.
include the should be voltages, in parenthesis on the same line. saves time.

q7 depends upon q5 so q7 could be good

but doing Q5, Q6 & Q7 will get the power supply corrected.

Then we shall see if the protect is satisfied, or if there is more to do.

frankly I would do the protect, at least C1, C2, Q6, Q7, D8 + 1 more 1n4004 across pins 9 & 10 & various e-caps.
Click to expand...
Tips noted for the future. And yes, even if new Q5-7 fixes this issue, I intend to go ahead and empirically replace several components on the protect board since they seem to eventually cause problems. Will update once I’m able to get parts in and replace them. Thanks!
 
markthefixer said:
when posting board readings, keep the reader's guessing to a minimum. Name the model, and the board # in the text close to the readings.
include the should be voltages, in parenthesis on the same line. saves time.

q7 depends upon q5 so q7 could be good

but doing Q5, Q6 & Q7 will get the power supply corrected.

Then we shall see if the protect is satisfied, or if there is more to do.

frankly I would do the protect, at least C1, C2, Q6, Q7, D8 + 1 more 1n4004 across pins 9 & 10 & various e-caps.
Click to expand...
My transistor replacements:
Q5/7 2sc1318–>ksc2690
Q6 2sa720–>ksa1013

These safe replacements? The legs on ksc2690 are pretty large. Any tips to get them to fit thru the holes on the pcb?
 
heat up a cutoff length of wire and while hot melt out the flux clogging the hole.

Needle nose pliers with 1/8" of the lead protruding can be used to manually force the hole clear.

do this from the foil side as to not lift the solder pad if you go through the opposite, component side you probably will.
 
markthefixer said:
heat up a cutoff length of wire and while hot melt out the flux clogging the hole.

Needle nose pliers with 1/8" of the lead protruding can be used to manually force the hole clear.

do this from the foil side as to not lift the solder pad if you go through the opposite, component side you probably will.
Click to expand...
Noted, thanks. Will give it a try. Otherwise those replacements look suitable? Wanna make sure I don’t cause a smoke show
 
No, no smoke show, the "master thread" for the 1250 shows Q5 with ksc2690, and Q7 with ksc2383.

master list: https://audiokarma.org/forums/index.php?threads/pioneer-recap-lists-sticky-suggestion.457663/
sx-950: https://www.audiokarma.org/forums/index.php?threads/recapping-sx-950.364598/

Q7 started life as a 2sc1318,and the ksc2383 is a pretty close replacement. Q7 only drives the phono preamp. never got hot.
Q5 started life as a 2sc1318, but it was running hot most of the time, so a more powerful transistor with greater heat dissipation (ksc2690) was used.
 
Protect board is satisfied with my work and the relay is clicking! Amp boards seem to work fine so far, sound is clear. Volume pot just needs a hit of deoxit. Now debating between leaving it all as is for now or doing the protect board. The protection board doesn’t look too labor intense so I’ll probably proceed and put new transistors and ecaps there.

Otherwise only issue I’m seeing is the tuner is like 0.5 off the mark on FM. I’ll probably leave that alone for now and see how much it bothers me. I have a scope but no signal generator, so I doubt I could align it on my own.

:-)
 
markthefixer said:
No, no smoke show, the "master thread" for the 1250 shows Q5 with ksc2690, and Q7 with ksc2383.

master list: https://audiokarma.org/forums/index.php?threads/pioneer-recap-lists-sticky-suggestion.457663/
sx-950: https://www.audiokarma.org/forums/index.php?threads/recapping-sx-950.364598/

Q7 started life as a 2sc1318,and the ksc2383 is a pretty close replacement. Q7 only drives the phono preamp. never got hot.
Q5 started life as a 2sc1318, but it was running hot most of the time, so a more powerful transistor with greater heat dissipation (ksc2690) was used.
Click to expand...
Now that it is working I’m noticing that the bass tone control is causing a low frequency noise when adjusting it. Cleaned the pot and it’s not as bad (maybe?) but still is present. I’m seeing in other threads this issue is possibly due to DC on the board. Would this be coming from? power supply board or elsewhere? Would like to zero in on the problem and fix it
 
Anonky said:
Now that it is working I’m noticing that the bass tone control is causing a low frequency noise when adjusting it. Cleaned the pot and it’s not as bad (maybe?) but still is present. I’m seeing in other threads this issue is possibly due to DC on the board. Would this be coming from? power supply board or elsewhere? Would like to zero in on the problem and fix it
Click to expand...
NEVERMIND! used my brain and since the 10 pin on the power supply had a voltage issue from the transistors on that board I replaced both 2sc1312 (known troublemaker) on the tone amp assy and the problem is fixed. WOO :-)
 
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