Pioneer SX-737 No Sound, No Relay Click, Lights On

[golfnut]

There is a very easy “build in way” to test the basic relay function. But it makes only sense, if the voltages at the power amp are close to the designed values.
It’s up to you, how you want to continue.

I’m game to proceed in whatever direction I’m led. I have taken many measurements and can continue to do so. However, there hasn’t been a clear indication of where my problem (s) are, meaning components. And I’m mean specific. I agree that the ps board needs to be close which I think mine may be. But, the 033 board is still not correct. @mrk229 had a great idea of starting all over at his direction, but I’m thinking the long distance communication (basically not having the unit on the table for the individuals giving instruction) has affected the continued advice. And, he is a busy person. I realize I’m at fault for not knowing what and where to look. Also, not knowing how to read things. But, I’m certainly willing to continue diagnosing this receiver. If it makes sense to start a new thread, and start all over, that can be done. Anyway, for now, I’m stuck. Any next steps are appreciated.
I’m certainly not complaining as I know anyone who helps is a volunteer source. So thanks.

 

[fucanay]

I don't think you need to begin a new thread and I don't know that you need to be led. You certainly shouldn't quit. This unit is in your hands and you are in control of the project. But building a comprehensive "reset" post would be useful. Having it all in one place rather than having to go from page to page would be good. Reading as many other posts with regards to these types of projects is helpful as well. As is patience and perseverance.

Give us:

• The original fault and the current state of the behavior
• What things you've already done by board (caps, transistors, adjustments, etc.)
• Any mistakes that were made along the way (backward parts, etc.)
• Overhead and closer up photos of all of the boards that have been worked on
• Voltages at each pin for each board along with the expected voltages (Power Supply, Protection and Power Amp)
• Whatever other relevant information you can provide in the clearest manner possible

 

[pa_200]

You can wait until one of the real electronic professionals would like to join and I would really wish that for you. It would be a great help and learning experience for everyone.

In the meantime, what I can offer is kind of a “mechanical assistance” with my running spare SX-737. I have it on my desk and all covers removed, so I can provide pictures, voltages and everything else one needs for comparison. That’s the way I fixed three of my receivers after Merlynski help me to fix the first one.
What I still need to learn, is trying to understand how the electronic parts work together or influence each other.

Right now, we / YOU have to concentrate on the AWH 033, the voltages coming from the Power Supply are close enough.

The difficulties so far, to understand what’s really going on with the unit,
- it's hard to see the relevant details in your pictures, that has to be better
- without good and clear images it’s a pain in the…
- your soldering skills
- providing the answer what was asked
- patience and waiting for the next steps, without running ahead or jumping around
- the time difference of 6 hours between yours and mine place
- sometime as well the language barrier

If you want to go my way, it will take time and a kind of “Apollo 13 Mission”.
I ask you what I need - you tell me what you see - I ask you more questions, you providing the answer what was asked and so on…..

Step by Step, starting from the basics like “Say everything again after Good Morning.”

 

[golfnut]

I don't think you need to begin a new thread and I don't know that you need to be led. You certainly shouldn't quit. This unit is in your hands and you are in control of the project. But building a comprehensive "reset" post would be useful. Having it all in one place rather than having to go from page to page would be good. Reading as many other posts with regards to these types of projects is helpful as well. As is patience and perseverance.

Give us:

• The original fault and the current state of the behavior
• What things you've already done by board (caps, transistors, adjustments, etc.)
• Any mistakes that were made along the way (backward parts, etc.)
• Overhead and closer up photos of all of the boards that have been worked on
• Voltages at each pin for each board along with the expected voltages (Power Supply, Protection and Power Amp)
• Whatever other relevant information you can provide in the clearest manner possible

I will generate this info tomorrow. Thanks for the advice.

 

[golfnut]

You can wait until one of the real electronic professionals would like to join and I would really wish that for you. It would be a great help and learning experience for everyone.

In the meantime, what I can offer is kind of a “mechanical assistance” with my running spare SX-737. I have it on my desk and all covers removed, so I can provide pictures, voltages and everything else one needs for comparison. That’s the way I fixed three of my receivers after Merlynski help me to fix the first one.
What I still need to learn, is trying to understand how the electronic parts work together or influence each other.

Right now, we / YOU have to concentrate on the AWH 033, the voltages coming from the Power Supply are close enough.

The difficulties so far, to understand what’s really going on with the unit,
- it's hard to see the relevant details in your pictures, that has to be better
- without good and clear images it’s a pain in the…
- your soldering skills
- providing the answer what was asked
- patience and waiting for the next steps, without running ahead or jumping around
- the time difference of 6 hours between yours and mine place
- sometime as well the language barrier

If you want to go my way, it will take time and a kind of “Apollo 13 Mission”.
I ask you what I need - you tell me what you see - I ask you more questions, you providing the answer what was asked and so on…..

Step by Step, starting from the basics like “Say everything again after Good Morning.”

Thanks for your help. What you mentioned is where I’m extremely lacking. That is, knowing why this pin voltage is not where it should be etc. I appreciate your willingness to compare my Receiver measurements to yours. As mentioned in the previous post, possibly a key is for me to do a “reset” or summary of where I’m at and what’s be done to date. I will start afresh with this info tomorrow taking all new pin measurements. Thanks to all.

 

[fucanay]

As a side note and some encouragement to not give up. I just figured out my 737's issue and corrected it. I put Q1 and Q2 on the protection board in backwards and it would go into protection when it got above 9-10 o'clock. One of those cases where I was trying to correct a condition and created the same condition by making a mistake. It pays to look things over and over again.

Keep at it, you can do it.

 

[golfnut]

As a side note and some encouragement to not give up. I just figured out my 737's issue and corrected it. I put Q1 and Q2 on the protection board in backwards and it would go into protection when it got above 9-10 o'clock. One of those cases where I was trying to correct a condition and created the same condition by making a mistake. It pays to look things over and over again.

Keep at it, you can do it.

That’s great! I will try to find out what’s going on in mine.

 

[fucanay]

That’s great! I will try to find out what’s going on in mine.

I'm going to be following along man. It's just parts and connections. But it's also my favorite receiver I've come across. I pulled mine out of service a couple of years ago to protect it from whatever was causing it to go into protection. If you can make yours go, I know you'll love it.

 

[golfnut]

I don't think you need to begin a new thread and I don't know that you need to be led. You certainly shouldn't quit. This unit is in your hands and you are in control of the project. But building a comprehensive "reset" post would be useful. Having it all in one place rather than having to go from page to page would be good. Reading as many other posts with regards to these types of projects is helpful as well. As is patience and perseverance.

Give us:

• The original fault and the current state of the behavior

The original fault in the unit, and still the same, was that there was no sound. The dbt (75w bulb) indicated a bright light at turn on then a dim glow thereafter. I was not familiar with the workings of this unit until reading about it here and there was no relay click. The unit can be tested at full power now and the below measurements were taken that way.

• What things you've already done by board (caps, transistors, adjustments, etc.)

PS Board AWR-057
All the caps were changed except the large horizontal cap. The caps changes were from this listing.
Power Supply Assembly (AWM-057)
Capacitors:

C8 330 uF 50v Electro (CEA) UPW1H331MPD 330 uF 50v
C9 330 uF 50v Electro (CEA) UPW1H331MPD 330 uF 50v
C10 330 uF 50v Electro (CEA) UPW1H331MPD 330 uF 50v
C11 220 uF 16v Electro (CEA) UPW1E221MPD 220 uF 16v
C12 220 uF 50v Electro (CEA) UPW1H221MPD 220 uF 50v
C13 100 uF 50v Electro (CEA) UHE1H101MPD 100 uF 50v
C16 220 uF 16v Electro (CEA) UPW1E221MPD 220 uF 16v
C17 22 uF 25v Electro (CEA) UPW1V220MDD 22 uF 25v
C18 100 uF 16v Electro (CEA) UPW1E101MED 100 uF 25v
C19 100 uF 35v Electro (CEA) UPW1V101MPD 100 uF 35v

Diode:
D9 WZ-140 14V, 1/2 Watt 1N5244B

Power Amplifier Assembly (AWH-033)
Only six transistors were replaced on this board. No caps were changed.

The 4 2sa726's (bce) were changed with ksa992 (ecb). The pinouts were the opposite 726, so the flat side was facing the opposite direction when 992's were installed.
The 2 2sc1451's (ebc) were changed to ksc3503 (ecb).
The above transistors pins were installed per the diagram on the board.

Protection Circuit Assembly (AWM-025)

Nothing was changed.

• Any mistakes that were made along the way (backward parts, etc.)

1. When testing the power assembly board, I shorted around pin 8. It blew one of the fuses underneath the unit. The fuse was replaced. All readings below are after that incident.
2. My desoldering and soldering skills are not the best. I have since bought a desoldering gun as well a lead solder. I was using lead free. Having never replaced a cap before, the cap was not pressed all the way to the board. Subsequent replacing other parts pushed the cap further in and therefore connection was lost. In addition, the pad came off so I had to scrape the board to bend the cap lead on the copper board and solder.
3. To my knowledge, no backward parts have been installed.

• Overhead and closer up photos of all of the boards that have been worked on

I have attached pics of both the 033 and 057 board.

• Voltages at each pin for each board along with the expected voltages (Power Supply, Protection and Power Amp)

The Power Supply Circuit AWR-057 (source @pa_200 )

First AC with black lead to the chassis
Mine/Pin/Expected
7.85 Pin 1, +7.5 VAC
7.61 Pin 2, from fuse F1 to pin 12 Protection Board +7.5 VAC out and to the Lamp Assy
38.4 Pin 3, to F2, +37 VAC
38.4 Pin 4, to F3, +37 VAC
0 Pin 5, = GND AC
36.4 Pin 6, to F4 +35 VAC
26.5 Pin 8, +27 VAC
26.5 Pin 11, to D3+D4 +27 VAC

Next DC with black lead to the chassis
-38.4 Pin 7, unregulated (it can vary) -38 vdc
35.5 Pin 9, + to C1, unregulated (it can vary) +35 vdc
-35.5 Pin 10, - to C2, unregulated (it can vary) -35 vdc
-13.3 Pin 12, regulated -13 vdc
-13.3 Pin 13, regulated -13 vdc
33.5 Pin 14, regulated + 36 vdc
29.2 (fluctuates)Pin 15, + 31.5 vdc
29.2 (fluctuates)Pin 16, + 31.5 vdc
16 to 19 Pin 17, + 24 vdc
0 Pin 18, = GND DC
12.9 Pin 19, regulated + 13.5 vdc
12.9 Pin 20, regulated + 13.5 vdc
12.9 (on AM if other selection 5.9) Pin 21, regulated + 13.5 vdc

Protection Assembly AWM-025
The below expected were from @mrk229
Mine/Pin/Expected
33.7 Pin 11 around +35 VDC
-13.2 Pin 2 around -13 VDC
5.0 to 5.5 Pin 1 should be in the very low 10's of mV DC (as pointed out to me, this is a major problem, but to my knowledge, no solution yet)
.31 to .70 Pin 3 Also in the very low 10's of mV DC. (high, but not bad. Could this be adjusted by DC offset and or Bias adj's?)

Here are my other readings on this board but I do not have or can't find the expected.
VDC unless noted
0 Pin4
5.0 to 5.9 Pin5
4.9 to 5.9 Pin6
.4 to .7 Pin7
.4 to .8 Pin8
34.0 Pin9
33.7 Pin10
.003 vdc or 7.62 vac Pin12

Power Amplifier Assembly AWH-033
These two expected are from @mrk229
Mine/Pin Expected
33.5 Pin 6 around +35 VDC
-13.3 Pin 10 around -10 VDC

Here are the rest of my readings VDC (you will see that several of the voltages jump around. I tried to get the highest and lowest during the fluctuations)
4.7 to 6.0 Pin1
4.5 to 6.3 Pin2
4.2 to 6.2 Pin3
0 Pin4
0 Pin5
6.7 Pin7
0 Pin8
-38.5 Pin9
0 Pin11
-38.5 Pin12
-38.5 Pin13
0 Pin14
.001 Pin15
0 Pin16
4.6 to 6.1 Pin17
4.2 to 6.0 Pin18
3.3 to 6.0 Pin19
4.0 to 6.3 Pin20
1.0 to 1.2 Pin21
35.7 Pin22
3.3 to 6.6 Pin23
-.001 to -.3 Pin24
-35.6 Pin25
4.5 to 6.0 Pin26
4.6 to 5.5 Pin27
-35.5 Pin28
-35.5 Pin29
4.7 to 6.0 Pin30
5.3 to 6.6 Pin31
35.6 Pin32
35.6 Pin33

• Whatever other relevant information you can provide in the clearest manner possible

My soldering skills are not the best. They are getting better. You'll see in earlier posts that I had to revisit some joints. Also, I was wondering if taking a measurement from the foil side would indicate whether the soldering was good.

As indicated above, we know that Pin1 on the 025 protection board is a serious problem.

The power supply board, 057, while not perfect, seems to be decent...but I do not know if it is good enough.

The power amp board, 033, I do not have many expected measurements so I'm not sure how far off any of the pins are.

Thanks for your willingness to continue to help and advise.

 

[golfnut]

I don't think you need to begin a new thread and I don't know that you need to be led. You certainly shouldn't quit. This unit is in your hands and you are in control of the project. But building a comprehensive "reset" post would be useful. Having it all in one place rather than having to go from page to page would be good. Reading as many other posts with regards to these types of projects is helpful as well. As is patience and perseverance.

Give us:

• The original fault and the current state of the behavior

The original fault in the unit, and still the same, was that there was no sound. The dbt (75w bulb) indicated a bright light at turn on then a dim glow thereafter. I was not familiar with the workings of this unit until reading about it here and there was no relay click. The unit can be tested at full power now and the below measurements were taken that way.

• What things you've already done by board (caps, transistors, adjustments, etc.)

PS Board AWR-057
All the caps were changed except the large horizontal cap. The caps changes were from this listing.
Power Supply Assembly (AWM-057)
Capacitors:

C8 330 uF 50v Electro (CEA) UPW1H331MPD 330 uF 50v
C9 330 uF 50v Electro (CEA) UPW1H331MPD 330 uF 50v
C10 330 uF 50v Electro (CEA) UPW1H331MPD 330 uF 50v
C11 220 uF 16v Electro (CEA) UPW1E221MPD 220 uF 16v
C12 220 uF 50v Electro (CEA) UPW1H221MPD 220 uF 50v
C13 100 uF 50v Electro (CEA) UHE1H101MPD 100 uF 50v
C16 220 uF 16v Electro (CEA) UPW1E221MPD 220 uF 16v
C17 22 uF 25v Electro (CEA) UPW1V220MDD 22 uF 25v
C18 100 uF 16v Electro (CEA) UPW1E101MED 100 uF 25v
C19 100 uF 35v Electro (CEA) UPW1V101MPD 100 uF 35v

Diode:
D9 WZ-140 14V, 1/2 Watt 1N5244B

Power Amplifier Assembly (AWH-033)
Only six transistors were replaced on this board. No caps were changed.

The 4 2sa726's (bce) were changed with ksa992 (ecb). The pinouts were the opposite 726, so the flat side was facing the opposite direction when 992's were installed.
The 2 2sc1451's (ebc) were changed to ksc3503 (ecb).
The above transistors pins were installed per the diagram on the board.

Protection Circuit Assembly (AWM-025)

Nothing was changed.

• Any mistakes that were made along the way (backward parts, etc.)

1. When testing the power assembly board, I shorted around pin 8. It blew one of the fuses underneath the unit. The fuse was replaced. All readings below are after that incident.
2. My desoldering and soldering skills are not the best. I have since bought a desoldering gun as well a lead solder. I was using lead free. Having never replaced a cap before, the cap was not pressed all the way to the board. Subsequent replacing other parts pushed the cap further in and therefore connection was lost. In addition, the pad came off so I had to scrape the board to bend the cap lead on the copper board and solder.
3. To my knowledge, no backward parts have been installed.

• Overhead and closer up photos of all of the boards that have been worked on

I have attached pics of both the 033 and 057 board.

• Voltages at each pin for each board along with the expected voltages (Power Supply, Protection and Power Amp)

The Power Supply Circuit AWR-057 (source @pa_200 )

First AC with black lead to the chassis
Mine/Pin/Expected
7.85 Pin 1, +7.5 VAC
7.61 Pin 2, from fuse F1 to pin 12 Protection Board +7.5 VAC out and to the Lamp Assy
38.4 Pin 3, to F2, +37 VAC
38.4 Pin 4, to F3, +37 VAC
0 Pin 5, = GND AC
36.4 Pin 6, to F4 +35 VAC
26.5 Pin 8, +27 VAC
26.5 Pin 11, to D3+D4 +27 VAC

Next DC with black lead to the chassis
-38.4 Pin 7, unregulated (it can vary) -38 vdc
35.5 Pin 9, + to C1, unregulated (it can vary) +35 vdc
-35.5 Pin 10, - to C2, unregulated (it can vary) -35 vdc
-13.3 Pin 12, regulated -13 vdc
-13.3 Pin 13, regulated -13 vdc
33.5 Pin 14, regulated + 36 vdc
29.2 (fluctuates)Pin 15, + 31.5 vdc
29.2 (fluctuates)Pin 16, + 31.5 vdc
16 to 19 Pin 17, + 24 vdc
0 Pin 18, = GND DC
12.9 Pin 19, regulated + 13.5 vdc
12.9 Pin 20, regulated + 13.5 vdc
12.9 (on AM if other selection 5.9) Pin 21, regulated + 13.5 vdc

Protection Assembly AWM-025
The below expected were from @mrk229
Mine/Pin/Expected
33.7 Pin 11 around +35 VDC
-13.2 Pin 2 around -13 VDC
5.0 to 5.5 Pin 1 should be in the very low 10's of mV DC (as pointed out to me, this is a major problem, but to my knowledge, no solution yet)
.31 to .70 Pin 3 Also in the very low 10's of mV DC. (high, but not bad. Could this be adjusted by DC offset and or Bias adj's?)

Here are my other readings on this board but I do not have or can't find the expected.
VDC unless noted
0 Pin4
5.0 to 5.9 Pin5
4.9 to 5.9 Pin6
.4 to .7 Pin7
.4 to .8 Pin8
34.0 Pin9
33.7 Pin10
.003 vdc or 7.62 vac Pin12

Power Amplifier Assembly AWH-033
These two expected are from @mrk229
Mine/Pin Expected
33.5 Pin 6 around +35 VDC
-13.3 Pin 10 around -10 VDC

Here are the rest of my readings VDC (you will see that several of the voltages jump around. I tried to get the highest and lowest during the fluctuations)
4.7 to 6.0 Pin1
4.5 to 6.3 Pin2
4.2 to 6.2 Pin3
0 Pin4
0 Pin5
6.7 Pin7
0 Pin8
-38.5 Pin9
0 Pin11
-38.5 Pin12
-38.5 Pin13
0 Pin14
.001 Pin15
0 Pin16
4.6 to 6.1 Pin17
4.2 to 6.0 Pin18
3.3 to 6.0 Pin19
4.0 to 6.3 Pin20
1.0 to 1.2 Pin21
35.7 Pin22
3.3 to 6.6 Pin23
-.001 to -.3 Pin24
-35.6 Pin25
4.5 to 6.0 Pin26
4.6 to 5.5 Pin27
-35.5 Pin28
-35.5 Pin29
4.7 to 6.0 Pin30
5.3 to 6.6 Pin31
35.6 Pin32
35.6 Pin33

• Whatever other relevant information you can provide in the clearest manner possible

My soldering skills are not the best. They are getting better. You'll see in earlier posts that I had to revisit some joints. Also, I was wondering if taking a measurement from the foil side would indicate whether the soldering was good.

As indicated above, we know that Pin1 on the 025 protection board is a serious problem.

The power supply board, 057, while not perfect, seems to be decent...but I do not know if it is good enough.

The power amp board, 033, I do not have many expected measurements so I'm not sure how far off any of the pins are.

Thanks for your willingness to continue to help and advise.

 

[pa_200]

Let’s confirm the actual situation.

After you worked on the Power Supply and the Protection board and you can power up with the DBT, there is no more short indicated and the bulb of the DBT stays dim after the first flash. So you can operate the unit on full wall-power without “magic-smoke.”

All Power Supply voltage are close, except for Pin 17 which goes to Pin 6 Equalizer Amp AWF 011.


Now we only work on the AWH 033 unless otherwise stated.
I still can confirm the correct position on both KSC3503. On our picture we see no print or any kind of marking that indicates the front side, which again is important for the pin out.



2. Please provide a picture of the big heatsink where we can clearly see and identify the print on the output transistors.

3. The marked part from to bottom side is the area of interest. Unfortunately in your pictures so far, that’s always the spot with the poorest quality.
Please move the wires out of way, get the main light to the side, produce no shadows and try to find a good distance, so we can zoom in see more details.
May be you have to try different angles or setups.

left side bottom:



right side bottom



Summary.
- Clear identification of the KSC3503 frontside.
- pictures in much better quality as before

 

[golfnut]

Here are pics of the 3503 transistors and the foil side of the transistors replaced.

 

[pa_200]

OK, let’s assume all changed transistors are installed correct.
What about nr.2
2. "Please provide a picture of the big heatsink where we can clearly see and identify the print on the output transistors."

 

[pa_200]

The most challenging errors to find, are always the self-produced problems!

Now disconnect the unit from power, we have to examine your new solder joints.
Get your DMM ready and set it to resistance.

The basic setup when measuring resistance. Set the DMM to resistance hold both probes together, check the internal resistance of your probe leads and write it down, so you can subtract the value from the follow-on measurement, if it's greater than 1 Ohm.

You have changed 6 transistors each with 3 legs. That means there are 18 solder pads and 18 traces you should thoroughly check, that they are not lifted or cracked.
Set the scale to the lowest resistance and take your time.
Hold one probe to your solder joint, follow the trace to the next solder joint and test with the second probe for continuity on one or two original and untouched pads.
Recheck with this procedure every single solder joint you have worked on.

If you find a lifted pad or open trace, don’t start resoldering right away. Mark the bad ones in a picture and tell us which ones are bad.

Before you continue, search for some instruction to improve your solder skills first. Youtube has some really good instruction for beginners.
Right now, there is a high chance, that you might produce even more issues.
I will give you some hints tomorrow.

And get some extra flux, together with Circuit Board Cleaner or Flux Remover and an old tooth brush for the final flux cleaning, if you don’t have them already.

 

[golfnut]

OK, let’s assume all changed transistors are installed correct.
What about nr.2
2. "Please provide a picture of the big heatsink where we can clearly see and identify the print on the output transistors."

 

[golfnut]

The most challenging errors to find, are always the self-produced problems!

Now disconnect the unit from power, we have to examine your new solder joints.
Get your DMM ready and set it to resistance.

The basic setup when measuring resistance. Set the DMM to resistance hold both probes together, check the internal resistance of your probe leads and write it down, so you can subtract the value from the follow-on measurement, if it's greater than 1 Ohm.

You have changed 6 transistors each with 3 legs. That means there are 18 solder pads and 18 traces you should thoroughly check, that they are not lifted or cracked.
Set the scale to the lowest resistance and take your time.
Hold one probe to your solder joint, follow the trace to the next solder joint and test with the second probe for continuity on one or two original and untouched pads.
Recheck with this procedure every single solder joint you have worked on.

If you find a lifted pad or open trace, don’t start resoldering right away. Mark the bad ones in a picture and tell us which ones are bad.

Before you continue, search for some instruction to improve your solder skills first. Youtube has some really good instruction for beginners.
Right now, there is a high chance, that you might produce even more issues.
I will give you some hints tomorrow.

And get some extra flux, together with Circuit Board Cleaner or Flux Remover and an old tooth brush for the final flux cleaning, if you don’t have them already.

Thanks for this. I was hoping I could test these to make sure they were soldered in.

All 18 soldering points of the 6 transistors I changed measured the same .2. I also measured the 4 ( 2 2sd357 and 2 2sb527) as well as the output drivers (2 2sd388 and 2 2sb541) and they also measured the same .2

 

[fucanay]

The original fault in the unit, and still the same, was that there was no sound. The dbt (75w bulb) indicated a bright light at turn on then a dim glow thereafter. I was not familiar with the workings of this unit until reading about it here and there was no relay click. The unit can be tested at full power now and the below measurements were taken that way.

PS Board AWR-057
All the caps were changed except the large horizontal cap. The caps changes were from this listing.
Power Supply Assembly (AWM-057)
Capacitors:

C8 330 uF 50v Electro (CEA) UPW1H331MPD 330 uF 50v
C9 330 uF 50v Electro (CEA) UPW1H331MPD 330 uF 50v
C10 330 uF 50v Electro (CEA) UPW1H331MPD 330 uF 50v
C11 220 uF 16v Electro (CEA) UPW1E221MPD 220 uF 16v
C12 220 uF 50v Electro (CEA) UPW1H221MPD 220 uF 50v
C13 100 uF 50v Electro (CEA) UHE1H101MPD 100 uF 50v
C16 220 uF 16v Electro (CEA) UPW1E221MPD 220 uF 16v
C17 22 uF 25v Electro (CEA) UPW1V220MDD 22 uF 25v
C18 100 uF 16v Electro (CEA) UPW1E101MED 100 uF 25v
C19 100 uF 35v Electro (CEA) UPW1V101MPD 100 uF 35v

Diode:
D9 WZ-140 14V, 1/2 Watt 1N5244B

Power Amplifier Assembly (AWH-033)
Only six transistors were replaced on this board. No caps were changed.

The 4 2sa726's (bce) were changed with ksa992 (ecb). The pinouts were the opposite 726, so the flat side was facing the opposite direction when 992's were installed.
The 2 2sc1451's (ebc) were changed to ksc3503 (ecb).
The above transistors pins were installed per the diagram on the board.

Protection Circuit Assembly (AWM-025)

Nothing was changed.




1. When testing the power assembly board, I shorted around pin 8. It blew one of the fuses underneath the unit. The fuse was replaced. All readings below are after that incident.
2. My desoldering and soldering skills are not the best. I have since bought a desoldering gun as well a lead solder. I was using lead free. Having never replaced a cap before, the cap was not pressed all the way to the board. Subsequent replacing other parts pushed the cap further in and therefore connection was lost. In addition, the pad came off so I had to scrape the board to bend the cap lead on the copper board and solder.
3. To my knowledge, no backward parts have been installed.


I have attached pics of both the 033 and 057 board.

The Power Supply Circuit AWR-057 (source @pa_200 )

First AC with black lead to the chassis
Mine/Pin/Expected
7.85 Pin 1, +7.5 VAC
7.61 Pin 2, from fuse F1 to pin 12 Protection Board +7.5 VAC out and to the Lamp Assy
38.4 Pin 3, to F2, +37 VAC
38.4 Pin 4, to F3, +37 VAC
0 Pin 5, = GND AC
36.4 Pin 6, to F4 +35 VAC
26.5 Pin 8, +27 VAC
26.5 Pin 11, to D3+D4 +27 VAC

Next DC with black lead to the chassis
-38.4 Pin 7, unregulated (it can vary) -38 vdc
35.5 Pin 9, + to C1, unregulated (it can vary) +35 vdc
-35.5 Pin 10, - to C2, unregulated (it can vary) -35 vdc
-13.3 Pin 12, regulated -13 vdc
-13.3 Pin 13, regulated -13 vdc
33.5 Pin 14, regulated + 36 vdc
29.2 (fluctuates)Pin 15, + 31.5 vdc
29.2 (fluctuates)Pin 16, + 31.5 vdc
16 to 19 Pin 17, + 24 vdc
0 Pin 18, = GND DC
12.9 Pin 19, regulated + 13.5 vdc
12.9 Pin 20, regulated + 13.5 vdc
12.9 (on AM if other selection 5.9) Pin 21, regulated + 13.5 vdc

Protection Assembly AWM-025
The below expected were from @mrk229
Mine/Pin/Expected
33.7 Pin 11 around +35 VDC
-13.2 Pin 2 around -13 VDC
5.0 to 5.5 Pin 1 should be in the very low 10's of mV DC (as pointed out to me, this is a major problem, but to my knowledge, no solution yet)
.31 to .70 Pin 3 Also in the very low 10's of mV DC. (high, but not bad. Could this be adjusted by DC offset and or Bias adj's?)

Here are my other readings on this board but I do not have or can't find the expected.
VDC unless noted
0 Pin4
5.0 to 5.9 Pin5
4.9 to 5.9 Pin6
.4 to .7 Pin7
.4 to .8 Pin8
34.0 Pin9
33.7 Pin10
.003 vdc or 7.62 vac Pin12

Power Amplifier Assembly AWH-033
These two expected are from @mrk229
Mine/Pin Expected
33.5 Pin 6 around +35 VDC
-13.3 Pin 10 around -10 VDC

Here are the rest of my readings VDC (you will see that several of the voltages jump around. I tried to get the highest and lowest during the fluctuations)
4.7 to 6.0 Pin1
4.5 to 6.3 Pin2
4.2 to 6.2 Pin3
0 Pin4
0 Pin5
6.7 Pin7
0 Pin8
-38.5 Pin9
0 Pin11
-38.5 Pin12
-38.5 Pin13
0 Pin14
.001 Pin15
0 Pin16
4.6 to 6.1 Pin17
4.2 to 6.0 Pin18
3.3 to 6.0 Pin19
4.0 to 6.3 Pin20
1.0 to 1.2 Pin21
35.7 Pin22
3.3 to 6.6 Pin23
-.001 to -.3 Pin24
-35.6 Pin25
4.5 to 6.0 Pin26
4.6 to 5.5 Pin27
-35.5 Pin28
-35.5 Pin29
4.7 to 6.0 Pin30
5.3 to 6.6 Pin31
35.6 Pin32
35.6 Pin33



My soldering skills are not the best. They are getting better. You'll see in earlier posts that I had to revisit some joints. Also, I was wondering if taking a measurement from the foil side would indicate whether the soldering was good.

As indicated above, we know that Pin1 on the 025 protection board is a serious problem.

The power supply board, 057, while not perfect, seems to be decent...but I do not know if it is good enough.

The power amp board, 033, I do not have many expected measurements so I'm not sure how far off any of the pins are.

Thanks for your willingness to continue to help and advise.

Thank you for all of that. I know you really worked hard on it. Outside of what pa_200 is asking of you, I would like the voltages on the pins on the power amplifier and the protection boards to be re-checked.

The reason is that you have:

1. "4.2 to 6.2 Pin3" on the Power Amp. It connects directly to "5.0 to 5.5 Pin 1" on the protection board.

and

2. "4.6 to 6.1 Pin17" on the Power Amp. It connects directly to ".31 to .70 Pin 3" on the protection board.

#1 could be true because they are in the same range (and very not good), but #2 cannot be true because they are different. They are directly connected and simply cannot be that far off. I think we need new measurements. Take your time, no shorts. Speedy work isn't the goal here. Get some hook clips for your multi-meter if you don't already have them. Turn the unit off while you're connecting them, back on to get the measurements.

If the first is correct, THIS IS A PROBLEM that need to be resolved. It would mean the Power Amplifier's Left Channel is cooked. But that would be good because that is leading us in the right direction. But let's get fresh measurements to confirm.

 

[golfnut]

Thank you for all of that. I know you really worked hard on it. Outside of what pa_200 is asking of you, I would like the voltages on the pins on the power amplifier and the protection boards to be re-checked.

The reason is that you have:

1. "4.2 to 6.2 Pin3" on the Power Amp. It connects directly to "5.0 to 5.5 Pin 1" on the protection board.

and

2. "4.6 to 6.1 Pin17" on the Power Amp. It connects directly to ".31 to .70 Pin 3" on the protection board.

#1 could be true because they are in the same range (and very not good), but #2 cannot be true because they are different. They are directly connected and simply cannot be that far off. I think we need new measurements. Take your time, no shorts. Speedy work isn't the goal here. Get some hook clips for your multi-meter if you don't already have them. Turn the unit off while you're connecting them, back on to get the measurements.

If the first is correct, THIS IS A PROBLEM that need to be resolved. It would mean the Power Amplifier's Left Channel is cooked. But that would be good because that is leading us in the right direction. But let's get fresh measurements to confirm.

Do you know how I can attach a video from my phone? I can attach pictures but wanted to show how the dmm moves around on those pins.

 

[golfnut]

What is nr2? Thanks

 

[fucanay]

Do you know how I can attach a video from my phone? I can attach pictures but wanted to show how the dmm moves around on those pins.

It's not the movement that concerns me. It's that you have many whole volts on pin 17 on the power amp and mv on pin 3 on the protection board that are electrically connected. That indicates to me that there wasn't enough care taken when taking measurements and I don't trust the numbers. See the image below from the service manual that shows how they are connected to each other and why it doesn't make sense.

Now separately from my distrust of these readings, Pins 1 and 3 on the protection board sense the voltage and determine whether to trigger the relay or not. If those readings are correct, there is no way it's coming out of protection. It need sto be the mv seen in pin 3, not the 5V seen on pin 1.

Either way, I don't trust the readings because of what you're showing on the Pin 17 to Pin 3 connection.

EDIT: Added some other points that I don't trust the measurements on because they just don't make any sense.

EDIT2: It occurred to me that you may have had the multimeter in different ranges at different times. Be careful to make sure that you are taking into account that in mv range 5.4 maybe 5.4mv not 5.4V. But still, we need to start this over.