Relay not clicking/engaging in a Marantz 2325

[angelaudio]

Voltages at H704/705 with R721 (27K ohm) removed from the circuit are as follows:

H704= B=16.1V , C=16.65V , E= -20.34V
H705= B= -19.67V , C= -20.37V , E= -20.34V

 

[angelaudio]

Would it be O.K. to switch the output transistors in from the other channel to see if that makes any difference?

 

[dankik]

Voltages at H704/705 with R721 (27K ohm) removed from the circuit are as follows:

H704= B=16.1V , C=16.65V , E= -20.34V
H705= B= -19.67V , C= -20.37V , E= -20.34V

Please check R721. It should be 270 Ohms (not 27K). RED-VIO-BRN
Please check your PCB for any cracks/cold solder joints on the trace that connects H704 and H705.
According to the schematic, H704(c) and H705(c) should be connected together... so should be the same voltage???
Did you measure from the transistor lead on the top of the board, or from the pad on the bottom?

 

[angelaudio]

Please check R721. It should be 270 Ohms (not 27K). RED-VIO-BRN
Please check your PCB for any cracks/cold solder joints on the trace that connects H704 and H705.
According to the schematic, H704(c) and H705(c) should be connected together... so should be the same voltage???
Did you measure from the transistor lead on the top of the board, or from the pad on the bottom?
View attachment 3285673
View attachment 3285674

I had the wrong resistor out, my mistake.

R721 measures exactly 270 ohms.

New readings with R721 removed and measured from the leads of the transistors are as follows:
H704: B= 19.82 , C= 20.56 , E= 20.53
H705: B= -20.9 , C= 20.59 , E= -20.96

Here is a picture of the traces from below:

 

[dankik]

OK, here's what I see:

• R721 removed from circuit
• H704(c) = 20v, H705(c) = 20v
• Both collector voltages should be 1.4v
• The only other components connected to that point are R716 & C704
• C704 should block the 1.4v from H701 & H703 collectors and no DC flowing through R716
• Conclusion: H705 is bad and not conducting... replace it and re-measure H704/H705 voltages
• Potentially, H704 could be bad also
• I think also you can see this because the previously measured H705(b) and (c) of -22.1v are the same (vs a diode drop of 0.6v)
• One more thing... can you measure the voltage of H712(c) and H713(c) with R721 out. Is it close to 0v?

 

[angelaudio]

With R721 Removed from circuit:

H712: C= 47V
H713: C= 47V

 

[dankik]

Should be about 0v???
Do you have the RCA cable plugged into J701? Apparently, grounds are not connected unless the cable is plugged in.
Careful... the other guy that has a 2325 connected his and the lead on one of his transistors turned white hot.

 

[angelaudio]

Should be about 0v???

I got 47V at both collectors of H712 & H713 with R721 removed. I double checked

 

[dankik]

See my question above about J701.

 

[angelaudio]

Wow white hot lead on a transistor doesn’t sound fun! Yes the RCA was plugged in during this test. I had it plugged into the DBT as well. H712/713 previously showed 60V at the collector when I did my initial readings in post #59. Must have gone down a bit because I’m plugged into the DBT?

 

[GRonald]

With R721 Removed from circuit:

H712: C= 47V
H713: C= 47V

Can you give me voltages at the emitter and base of H712/H713 and the voltage on the collector of H707
and as @dankik suggested, you may have to replace H704/705 with new transistors. And I would also replace H707
In sequence change H707, test, Then H705, Test and Then H704. Test

 

[angelaudio]

Can you give me voltages at the emitter and base of H712/H713 and the voltage on the collector of H707
and as @dankik suggested, you may have to replace H704/705 with new transistors. And I would also replace H707
In sequence change H707, test, Then H705, Test and Then H704. Test

I will get those voltages for you soon.

I am thinking of buying a recap kit from AK member eastpoint. In the interest of saving money I figured it’s not such a bad idea, especially considering that ordering a few parts at a time could add up very quickly seeing as shipping from mouser is almost $10. I know maybe not all the parts on all the boards need to be replaced but at this point in time I can’t afford to order two or three transistors at a time so this seems to me a more economical alternative, buying the kit from eastpoint that is.

I'm still very much interested in learning to track down the source of the problem, though so I don’t want you guys to think that I’m giving up on that. I just feel a bit guilty because I’d get the kit in, replace the parts that you guys are mentioning, then proceed to change out a bunch of other parts as well. I’m not sure how to go about it moving forward.

 

[angelaudio]

With

Can you give me voltages at the emitter and base of H712/H713 and the voltage on the collector of H707
and as @dankik suggested, you may have to replace H704/705 with new transistors. And I would also replace H707
In sequence change H707, test, Then H705, Test and Then H704. Test

With R721 still removed from circuit:

H712: E= 48V , B= 47.47V
H713: E= 48V , B= 39.25V
H707: C= 47.6V

 

[dankik]

Pretty much the same voltages as before (except a little lower voltage readings due to the DBT, 48v vs 61v).
Good the get a kit, but you should troubleshoot the problem before introducing yet another variable into the debugging process.

 

[angelaudio]

Ok. I just ordered the kit so once I get it in I will change out the parts that you and gronald suggested first and post the readings. Is there any risk of damaging the new components if, let’s say, there are still other out-of-spec components on the board?

 

[dankik]

I tried to follow the 60v voltage around the schematic to see what would cause it to be where it shouldn't.
Can you check to make sure C712 is not shorted.
Also, check H706 for a collector to emitter short.

Here is my logic:

• H706(c) has +62v vs +0.6v. It has to come from somewhere?
• Case 1: H706 has an emitter to collector short.
• Case 2: C712 has a short causing the +60v rail to short to the blue dotted line going to H706(c), H715(c), H714(c)(b) vs what is should be 0.6v

 

[dankik]

Is there any risk of damaging the new components if, let’s say, there are still other out-of-spec components on the board?

There are two problems with blindly changing components without knowing the root cause of the problem:

1. Now you have introduced new components into the mix of possible problems
2. You could damage the new components if, for example, a voltage is too high or drawing too much current

I would suggest first changing only the components that we suspect may be causing the problem (one at a time), then retest to see if it made a difference.
Once the board voltages get back to normal and it appears to be working, then start with the re-cap and new transistors.
Replace, then test... and repeat. Then, if a problem pops up you will know it was the last change that may have caused it. Change them all and you won't know where to start.

 

[angelaudio]

I tried to follow the 60v voltage around the schematic to see what would cause it to be where it shouldn't.
Can you check to make sure C712 is not shorted.
Also, check H706 for a collector to emitter short.
View attachment 3287756
Here is my logic:

• H706(c) has +62v vs +0.6v. It has to come from somewhere?
• Case 1: H706 has an emitter to collector short.
• Case 2: C712 has a short causing the +60v rail to short to the blue dotted line going to H706(c), H715(c), H714(c)(b) vs what is should be 0.6v

Should I put R721 back in? And for testing H706 emitter to collector should I pull it or test in circuit?

I will pull and check C712 now.

 

[angelaudio]

C712= 430 picofarads, SM says it should be 100pF+or-10%

 

[dankik]

Keep R721 out for now.
Test H706 emitter to collector out of circuit, but also when you pull it out to test can you measure the resistance from the H706 solder pads from the emitter to collector to check for a board short.
C712 is out of tolerance, but not a short so it probably needs to be changed, but not the cause of the 60v.
I still can't figure out why the voltage divider network that connects the +60v to -60v does not have the correct voltage at the middle? It should be close to 0v?
Maybe do a quick resistance check in circuit. Compare measured R of R724 (560 Ohm) compared to R725 (560 Ohm) and R722 (27K) to R723 (27K). Or compare with your good deck.