Marantz 2325 right channel wont work regardless of P700

C

CavScout

Super Member
I just rebuilt my Marantz 2325 P800 board and P700 boards.

I noticed the Right channel does not work.

Long story short...I swapped the P700 boards with each other and this made no difference. The problem remained ON THE RIGHT SIDE.

So I hooked a pre amp to the 2325 Main In to isolate a bit...same result.

I am betting this problem goes back to the power supply board but I am looking for some guidance.

I thought the power supply was a "single" type board. Is it possible that there is something on that board that is specific to the right channel ?
Any help is greatly appreciated
 
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I can tell you that the only specific thing would be the path that the amp outputs go to reach the relay and then from the relay back out two other pins. Nothing else is channel specific. Maybe a wire broke with the work that was done? It's not hard to have that happen!
 
@rBuckner is right, the interface to the P700 board is minimal, only +60v, -60v, Gnd power and signal in and out.
First, measure the voltages on the R channel board.
CAUTION!! this is 60VDC, do not touch or short this voltage.
(Edit: It could be the relay contacts, but let's check everything else first.)

1690898603996.png
Next, we can check the Audio In signal path. With power Off, measure the resistance between the center conductor of the R Main In jack on the receiver back panel to the P700 J701 RCA Audio In board input. It should be close to 0 ohms.
1690899330202.png

***NOTE: Have you tried to externally jumper the Pre-Out to Main In jacks using an RCA audio cable. Sometimes the self-shorting contacts inside the connector are oxidized and don't make contact.

Next, we can check the Audio Out path to the protection relay. With power Off, check the continuity between the P700 Audio Out and P700 J808, the input to the relay. It should read close to 0 ohms.
1690899574120.png
 
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dankik said:
@rBuckner is right, the interface to the P700 board is minimal, only +60v, -60v, Gnd power and signal in and out.
First, measure the voltages on the R channel board.
CAUTION!! this is 60VDC, do not touch or short this voltage.
(Edit: It could be the relay contacts, but let's check everything else first.)

View attachment 2947362
Next, we can check the Audio In signal path. With power Off, measure the resistance between the center conductor of the R Main In jack on the receiver back panel to the P700 J701 RCA Audio In board input. It should be close to 0 ohms.
View attachment 2947386

***NOTE: Have you tried to externally jumper the Pre-Out to Main In jacks using an RCA audio cable. Sometimes the self-shorting contacts inside the connector are oxidized and don't make contact.

Next, we can check the Audio Out path to the protection relay. With power Off, check the continuity between the P700 Audio Out and P700 J808, the input to the relay. It should read close to 0 ohms.
View attachment 2947394
Click to expand...
Can you please clarify P700 "audio out" ?
Thank you
 
dankik said:
@rBuckner is right, the interface to the P700 board is minimal, only +60v, -60v, Gnd power and signal in and out.
First, measure the voltages on the R channel board.
CAUTION!! this is 60VDC, do not touch or short this voltage.
(Edit: It could be the relay contacts, but let's check everything else first.)

View attachment 2947362
Click to expand...
J707 is 58.7 vdc
J706 is 58.7 vdc
J705 is - 58.5 vdc
J704 is - 58.5 vdc
dankik said:
Next, we can check the Audio In signal path. With power Off, measure the resistance between the center conductor of the R Main In jack on the receiver back panel to the P700 J701 RCA Audio In board input. It should be close to 0 ohms.
View attachment 2947386
Click to expand...
see photo...it reads .901 M ohms

dankik said:
***NOTE: Have you tried to externally jumper the Pre-Out to Main In jacks using an RCA audio cable. Sometimes the self-shorting contacts inside the connector are oxidized and don't make contact.
Click to expand...
Yes I have tried this and the results were the same.
dankik said:
Next, we can check the Audio Out path to the protection relay. With power Off, check the continuity between the P700 Audio Out and P700 J808, the input to the relay. It should read close to 0 ohms.
View attachment 2947394
Click to expand...
Please see photo.
.537 M Ohms
 

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Sorry, my error. The last test should have said continuity between P700 Audio Out to P800 J808 (input to the relay).
 
1690903522968.png
But, it looks like this might be the problem. Please clarify this measurement. You connected your ohm meter to the center conductor of the jack on the back panel to the center conductor of the other end of the cable with the RCA connector like shown in the 2nd photo? If so, it looks like this is the problem, it should be 0 ohms. The cable that goes from the R Main In jack to the P700 RCA plug is open.

You can verify that this is the problem by using an external RCA cable to connect from the RCA R Preamp Output on the back panel to the P700 Audio In jack (J701) on the R channel and see if you now get audio out from the speakers.
 
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dankik said:
View attachment 2947460
But, it looks like this might be the problem. Please clarify this measurement. You connected your ohm meter to the center conductor of the jack on the back panel to the center conductor of the other end of the cable with the RCA connector like shown in the 2nd photo? If so, it looks like this is the problem, it should be 0 ohms. The cable that goes from the R Main In jack to the P700 RCA plug is open.

You can verify that this is the problem by using an external RCA cable to connect from the RCA R Preamp Output on the back panel to the P700 Audio In jack (J701) on the R channel and see if you now get audio out from the speakers.
Click to expand...
I ran an external RCA as you mentioned but still no sound from right channel
 
Is it possible that the problem is the PU01 board ?
I get no sound on the R channel either via speakers or headphones and it seems the J810 & J811 wires run from the P800 board up to the speaker/headphone area (PU01 board).
Thoughts ?
 
Good call. I was thinking the same. OK, let's check the path from the other side of the relay to the speaker switch board.
Power off, check continuity from P800, J811 to PU01 (push switch board) JU12. It should be 0 ohms.
 
Continuity test from relay output to speaker switches should be between J811(R channel) on P800 to JU12 on PU01.

1690911594241.png
 
Hmmm... looks like the schematic has an error where the speaker switches do not match the speaker terminals. Main switch is connected to Remote terminals.
With power off, and both Main and Remote speaker buttons pressed in, measure the resistance between JU12 and both the Main R channel red terminal, should be 0 ohms. Also, check JU12 to Remote R channel red terminal. Try the L also while you are at it in case the schematic is in error.
1690930125569.png
 
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rBuckner said:
Yes!
Click to expand...
I have a spare relay (doesn't fit but I can wire it for testing)
Should I do that or does my continuity test from J811 (P800) to J012 (PU01) eliminate that possibility ?
dankik said:
Hmmm... looks like the schematic has an error where the speaker switches do not match the speaker terminals. Main switch is connected to Remote terminals.
With power off, and both Main and Remote speaker buttons pressed in, measure the resistance between JU12 and both the Main R channel red terminal, should be 0 ohms. Also, check JU12 to Remote R channel red terminal. Try the L also while you are at it in case the schematic is in error.
View attachment 2947765
Click to expand...
Right now since I dug my way back to the PU01 board I figured I would closely inspect and clean the switches.
I found a small spring retainer loose and just sitting between some wiring. Upon pulling the switches for cleaning one by one I found that the Low Filter was missing a spring and the retainer (luckily I have some spares).
I also found some bent pins on that board that probably busted some of the solder joints loose so I will re-flow those or better.
Also found a wire disconnected to the headphone input.
I will do these repairs and report back
 

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Update: Good news. Both amps are working now.
After testing successfully (with an external pre amp) I went ahead and replaced the capacitors.

Thanks for the help guys as I could not have done it without you.

I have a different problem to move onto now though as the Preamp on the unit has some problems.
In fact the only way to test the amps is to drive with an external pre amp.
I will start a new thread.
 
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