SX-950 Looking for help bringing it on home!

all the better use that then
I did verify leads first time I pulled the 992's and leads were as they should be. I didn't put 726's back in yet. I have to sign off for the night. Can you give me a couple things to check to do later tonight or tomorrow AM. Thanks Pete.
 
putting the 726.s back in will at least narrow that down ... this is puzzling me . please check the replacements whilst they are out ..
hope you are not saying those transistors are omitted right now ?
 
putting the 726.s back in will at least narrow that down ... this is puzzling me . please check the replacements whilst they are out ..
hope you are not saying those transistors are omitted right now ?
992's are in. Will pull and put 726's back and approach this like it just happened and recheck everything. Has to be something that's right in front of my face.
 
IMG_0629.JPG
992's are in. Will pull and put 726's back and approach this like it just happened and recheck everything. Has to be something that's right in front of my face.
Last night went over everything on power amp board. Then moved to EQ board since that was only other thing changed since receiver was functional. Found 1485's installed backwards. Verified with pic of rebuilt board from another thread. Hadn't looked at this board as it had passed DBT. Looking back, this board initially didn't pass DBT, but had started with unit on and used switch on DBT to open circuit. Switched unit off, DBT on and passed. Probably needed to heed first result. With correct transistor orientation on EQ board still doesn't pass DBT. Included pic of EQ board. My plan now is to recheck solder joints on EQ board, were done late last night. Reflow Q5-Q12 on power amp and reinstall 726's. If no change install new 992's and check all resistors and diodes. It seems like there has to be something that was disrupted during the initial 992 installation on power amp. I'll repost when I've gotten through this. Please let me know if I'm going in the wrong direction. Thanks.
 
Always check your supply voltages after any change or fix to a fault. It is also possible to have fried or taken out of spec something else like a resistor with parts being installed incorrectly. Check circuit bias voltages against the schematics.
The bjt orientations are printed on the pcb, we know that c1845 are ECB looking at the flat face, leads down, from left to right. I even test new ones out with the diode test function on the DMM before I install a new one. if it is a differential pair purpose, I match for Vbe within a 1-2mV.
 
Always check your supply voltages after any change or fix to a fault. It is also possible to have fried or taken out of spec something else like a resistor with parts being installed incorrectly. Check circuit bias voltages against the schematics.
The bjt orientations are printed on the pcb, we know that c1845 are ECB looking at the flat face, leads down, from left to right. I even test new ones out with the diode test function on the DMM before I install a new one. if it is a differential pair purpose, I match for Vbe within a 1-2mV.
Should I start with EQ board as that is most likely where problems began? Hook to DBT check pins 3 & 5?
 
if you have isolated the problem to the EQ, then focus on that. there are 3 bjts per channel. I have not read this thread thoroughly, you have had multiple problems which seem to be associated to incorrectly installing components. you also mention 1485, I assume that is a typo for ksc1845f
if both channels have the same issue then it is a common problem.
check the supply voltages to the eq, iirc it has -19V that is used for this eq ckt. it is possible a fault is causing the supply V to be out of spec, so isolation maybe required.
 
if you have isolated the problem to the EQ, then focus on that. there are 3 bjts per channel. I have not read this thread thoroughly, you have had multiple problems which seem to be associated to incorrectly installing components. you also mention 1485, I assume that is a typo for ksc1845f
if both channels have the same issue then it is a common problem.
check the supply voltages to the eq, iirc it has -19V that is used for this eq ckt. it is possible a fault is causing the supply V to be out of spec, so isolation maybe required.
I full recap on this unit. Hooked to system and used for 2 days. Sounded a little off at end of 2 days, so decided to change out known problematic transistors. Transistors swapped out with known replacements from AK threads. Fails DBT. Found 1485f's improperly installed on EQ board. Installed correctly still fails DBT. Will follow your previous instructions unless you tell me this update changes anything. Thanks.
 
I full recap on this unit. Hooked to system and used for 2 days. Sounded a little off at end of 2 days, so decided to change out known problematic transistors. Transistors swapped out with known replacements from AK threads. Fails DBT. Found 1485f's improperly installed on EQ board. Installed correctly still fails DBT. Will follow your previous instructions unless you tell me this update changes anything. Thanks.
AWF-011
Pin 1 0v
Pin 2 -1.2v
Pin 3 0
Pin 4 0
Pin 5 0
Pin 6 1.55v
Pin 7 0
 
You are still saying 1485, did you read my email?
it was working properly b4 you changed ecaps, then it went off, so why would you assume it was bjts, if they were working properly b4 your ecap? I would focus on what you did to throw it off. Throwing it off is a tough one to troubleshoot for? since I have no idea what that means.
I will look at the schematic.
 
You are still saying 1485, did you read my email?
it was working properly b4 you changed ecaps, then it went off, so why would you assume it was bjts, if they were working properly b4 your ecap? I would focus on what you did to throw it off. Throwing it off is a tough one to troubleshoot for? since I have no idea what that means.
I will look at the schematic.
Yes I mean 1845's. My first post explains in detail the state of the receiver. Wasn't running fine before recap. Sounded pretty good after recap but suspected I needed to replace known troublesome transistors in EQ and power amp boards. Was in the process of rechecking pin outs and looking for problems when you entered the conversation. I'm a hobbiest learning as I go. I appreciate any assistance I can get. Some of the acronyms you're using are over my head.
 
Well that is obvious, you have no supply voltages, you have a case where either you have one of these situations, eq shorting out the power supply &/or it is damaged and needs repair.
So you have to figure out what you damaged. You can remove the sq posts from EQ pins 2,6, make sure they do not short to ground, check the supply V's again, if off then you need to fix that, probably a smoked Q6,7,R19, R11 (AWR-101)

B4: before
ckt: circuit
Eq: equalizer or phono pre-amp
what else
 
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Well that is obvious, you have no supply voltages, you have a case where either you have one of these situations, eq shorting out the power supply &/or it is damaged and needs repair.
So you have to figure out what you damaged. You can remove the sq posts from EQ pins 2,6, make sure they do not short to ground, check the supply V's again, if off then you need to fix that, probably a smoked Q6,7,R18, R11

B4: before
ckt: circuit
Eq: equalizer or phono pre-amp
what else
 
Will work on that. Thanks.
Pin 2 AWF-011 pulled, -1.9V
Pin 6 AWF-011 pulled, 1.76V

Q6 AWR-101 pulled (2SA818) EBC pinout PNP

B-E OL
B-C OL
E-B .598V
C-B .555V
C-E OL

Q7 AWR-101 pulled (2SC1628) EBC pinout NPN

B-E .596V
B-C .584V
E-B OL
C-B OL
C-E OL

R11 AWR-101 pulled measured 1 ohm
R19 AWR-101 pulled measured 99.6 K
 
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