Marantz 2325 Stuck at Power Supply Board... I think

[Tonyawesome]

I've done my very best trying to not have to post on the board but I'm really at a loss. Yes, I'm a handy guy who kinda understands electronics (but can use a multimeter just fine) but doesn't have a great grasp on everything. Should I have attempted the repair? Probably not. But I've done recap jobs on many electronics so what the hell... right?

I didn't do it totally blind and my main guides were these two gentlemen's work:

http://audiokarma.org/forums/index.php?threads/marantz-2325-my-first-published-restoration.681573/

http://audiokarma.org/forums/index....n-and-upgrade-of-a-marantz-2325.689386/page-3

Anyway, here's the details:

It used to have sound. Kinda. It did have a relay click.

Recapped PO1 Tone Board, Power Supply, new relay, changed the filter caps.



Now lets get into the rest.

I did not do one board at a time and test. I won't make that mistake again. I don't even change more than one component without testing now. But I believe I have found at least what board is the problem.

The relay does NOT click. I have pulled each amp board separately to see if one board is causing the problem. Nothing changed. I went ahead and changed all the resistors/transistors (i'm waiting on a transistor/diode tester to confirm their functionality) on the power supply board. No change.

The lights do work and I changed them to LED's before I started working on the receiver itself. Priorities huh.

The pre-amp is fully functional after hooking to another receiver. Both channels.

I have cleaned all pots. All switches are functional except multiplex. May by broken.

I've checked continuity and leads on bottom of PS board. Re-flowed solder.

No smoked parts that I can see.



I am concerned about the amp boards in a few spots. On some areas the board is noticeably darker from heat. I tried to capture it the best I could.

Here are the output voltages I got from the power supply board:

801 - 36.7v AC
802 - 36.7v AC
803 - 0v
804 - 35v DCV
805 - 35 DCV
806 - 20V
807 - 13.1V
808 - .5v DC
809 - .5c DC
810 - 0
811 - 0

H808 - 47.5 DC measured from top metal
H809 - 48.4 DC measured from top metal

Fuse at J813-J812 46.1 and 46.2 respectively.


Apologies if this is out of order or difficult to follow.

 

[wurlyman]

I've done my very best trying to not have to post on the board but I'm really at a loss. Yes, I'm a handy guy who kinda understands electronics (but can use a multimeter just fine) but doesn't have a great grasp on everything. Should I have attempted the repair? Probably not. But I've done recap jobs on many electronics so what the hell... right?

I didn't do it totally blind and my main guides were these two gentlemen's work:

http://audiokarma.org/forums/index.php?threads/marantz-2325-my-first-published-restoration.681573/

http://audiokarma.org/forums/index....n-and-upgrade-of-a-marantz-2325.689386/page-3

Anyway, here's the details:

It used to have sound. Kinda. It did have a relay click.

Recapped PO1 Tone Board, Power Supply, new relay, changed the filter caps.



Now lets get into the rest.

I did not do one board at a time and test. I won't make that mistake again. I don't even change more than one component without testing now. But I believe I have found at least what board is the problem.

The relay does NOT click. I have pulled each amp board separately to see if one board is causing the problem. Nothing changed. I went ahead and changed all the resistors/transistors (i'm waiting on a transistor/diode tester to confirm their functionality) on the power supply board. No change.

The lights do work and I changed them to LED's before I started working on the receiver itself. Priorities huh.

The pre-amp is fully functional after hooking to another receiver. Both channels.

I have cleaned all pots. All switches are functional except multiplex. May by broken.

I've checked continuity and leads on bottom of PS board. Re-flowed solder.

No smoked parts that I can see.



I am concerned about the amp boards in a few spots. On some areas the board is noticeably darker from heat. I tried to capture it the best I could.

Here are the output voltages I got from the power supply board:

801 - 36.7v AC
802 - 36.7v AC
803 - 0v
804 - 35v DCV
805 - 35 DCV
806 - 20V
807 - 13.1V
808 - .5v AC
809 - .5c AV
810 - 0
811 - 0

H808 - 47.5 measured from top metal
H809 - 48.4 measured from top metal

Fuse at J813-J812 46.1 and 46.2 respectively.


Apologies if this is out of order or difficult to follow.

J810 & 811 come off the relay and would be '0' if it is open. Other voltages are close. 806 should be 19 and 807 is 14. My schematic .jpeg is too large to post or I would share it with you.

 

[Tonyawesome]

J810 & 811 come off the relay and would be '0' if it is open. Other voltages are close. 806 should be 19 and 807 is 14. My schematic .jpeg is too large to post or I would share it with you.

So 810-811 and the relay are the issue?

Thank you for your help btw

 

[petehall347]

808 809 DC ?

 

[Tonyawesome]

808 809 DC ?

Sorry. Yes they are DC

 

[petehall347]

dc voltages for
h805 BCE
h806 BCE
h807 BCE
?

 

[Tonyawesome]

dc voltages for
h805 BCE
h806 BCE
h807 BCE
?

H805
B. .06v
C. 1.09v
E. 0

H806
B. 1.09v
C. .52v
E. 0

H807
B. .53v
C. .53v
E. 0

 

[petehall347]

check r817 470 ohms

 

[petehall347]

h806 is wacky seems emitter and collector are maybe swapped .

 

[Tonyawesome]

h806 is wacky seems emitter and collector are maybe swapped .

I will check both suggestions

 

[Tonyawesome]

check r817 470 ohms

I had a 470kohm resistor in there. Put in the correct one.

CLICK. Just like that.

I'm really amazed you could pinpoint that.


I can never thank you enough.

If you happened to have a minute, could you tell me how you deduced that resistor being the problem? I attached the board schematic. I'd love to learn something today.

 

[petehall347]

was lack of voltage at h807 collector whilst its base voltage was too low to switch the transistor on .
with 807 being off the voltage should have been much higher at its collector .
hope you understand that .

 

[Tonyawesome]

was lack of voltage at h807 collector whilst its base voltage was too low to switch the transistor on .
with 807 being off the voltage should have been much higher at its collector .
hope you understand that .

Makes plenty of sense actually. Thank you so much for the help.

I biased the dc offset and made sure no DC was at the speaker terminals.

But, I'm tasked with a while new set of problems.

Both channels are working. I do get a hum on main speakers.

Here's the VERY STRANGE part.

Most of the pots are still finicky. I think they'll need another shot with deoxit. I think there is some kind of ground loop/short. Sometimes there is a hum when I come near the tone knobs/ right side of unit. Sometimes it isn't there. Sometimes there is a loud crackle/pop when I touch the tone knobs .And one time I saw a spark at the relay and it cut the speakers off for a few seconds and then came back on.

The FM Dolby knob has a lot of sayosa power on what the unit wants to do. Maybe that's normal. I dunno.

 

[Dingman]

Sounds like your controls need another crazy good cleaning.
That relay - replace it with new.
Then clean the controls again!

 

[petehall347]

maybe loose nuts on the controls

 

[Tonyawesome]

Sounds like your controls need another crazy good cleaning.
That relay - replace it with new.
Then clean the controls again!

It... Is a new relay.

 

[Tonyawesome]

maybe loose nuts on the controls

They were hand tight.

 

[tarior]

maybe loose nuts on the controls

Loose nut with a soldering iron!







Just givin' ya' a hard time, OP.

 

[wurlyman]

Don't forget the 2325 quirk, the bottom cover is part of the grounding loop and the hum will probably stop when you put it back on.

 

[Tonyawesome]

Don't forget the 2325 quirk, the bottom cover is part of the grounding loop and the hum will probably stop when you put it back on.

I wansnt aware of that. Thanks for the heads up.