Marantz 3250b left channel cutting out

[sarris28]

I have a rack consisting of a marantz 3250b and 300dc, and the left channel cuts out. It goes silent while the right continues to play music, until I turn off the speakers, max out the volume until the vu meter starts showing something, lower it again, and turn the speakers back on. Doing this only gets me about 2 minutes of listening before having to do this again. I am planning on doing a recapping of the 3250b, and while researching, I read that my issue could be because of the relay, which is listed in the service manual as

Reference Designation: LN01
Part Number: LY20240120
Description: Relay, 24V
Could this be the issue, and if so, how do I get this replacement part?
Should I also replace the transistors and diodes?

 

[kwayde]

I have a rack consisting of a marantz 3250b and 300dc, and the left channel cuts out. It goes silent while the right continues to play music, until I turn off the speakers, max out the volume until the vu meter starts showing something, lower it again, and turn the speakers back on. Doing this only gets me about 2 minutes of listening before having to do this again. I am planning on doing a recapping of the 3250b, and while researching, I read that my issue could be because of the relay, which is listed in the service manual as

Reference Designation: LN01
Part Number: LY20240120
Description: Relay, 24V
Could this be the issue, and if so, how do I get this replacement part?
Should I also replace the transistors and diodes?

Have you tried cleaning all of the switches?

 

[sarris28]

Have you tried cleaning all of the switches?

No, I am waiting for an order of deoxit f5. Was that the right one?

 

[kwayde]

No, I am waiting for an order of deoxit f5. Was that the right one?

I use F5 on resistive contacts like bass, volume, balance, treble, etc.

For the other switches that have metal to metal contacts I use CRC QD Electronic Cleaner.

 

[sarris28]

Should I clean the green circles with f5 and the red circles with crc?
And, what should I use for the potentiometers?

 

[kwayde]

I never spray anything into a power switch. It it needs attention I take it apart.

The other 8 circled in red are metal to metal. Use CRC. To really get them clean they should be disassembled and cleaned but if you're not comfortable attempting that don't. There are tiny parts that can be lost. They need to be reassembled correctly too.

I don't know the mechanics of the contour and volume controls. If they have resistive pads then use the F5. Some volume pots use resistors connected to metal contacts so you'll have to look at how yours is made. I've never been inside one of these.

This may help:
https://audiokarma.org/forums/threads/the-idiots-guide-to-using-deoxit-revisited.207005/

 

[Namlook]

Also check the relay.

 

[Lavane]

I never spray anything into a power switch. It it needs attention I take it apart.

The other 8 circled in red are metal to metal. Use CRC. To really get them clean they should be disassembled and cleaned but if you're not comfortable attempting that don't. There are tiny parts that can be lost. They need to be reassembled correctly too.

I don't know the mechanics of the contour and volume controls. If they have resistive pads then use the F5. Some volume pots use resistors connected to metal contacts so you'll have to look at how yours is made. I've never been inside one of these.

This may help:
https://audiokarma.org/forums/threads/the-idiots-guide-to-using-deoxit-revisited.207005/

After using CRC I use a couple of drops of Fader Lube on sliders.
Ive done this with several Marantz preamps. The models 33,3300, and 3200.
It kept them from becoming scrstchy or intermittent again.

 

[painttoad]

I don't know the mechanics of the contour

i am unfamiliar with these exact sliders but 95% of the ones i've taken apart are hybrid. metal contact on one side, resistive carbon track recessed in the center. not including any metal contacts for leds on the opposite side.

the other 5% use only carbon tracks.

if a spray an pray is performed then f5 should be used. if disassembling then one can use each if and where needed.

 

[sarris28]

Also check the relay.

How do I go about this?
Update: I cleaned all of the pots sliders and push-buttons, and the issue seems to be gone for the most part, except at startup. But after I go through the routine I know all too well, it hasn't cut out on me.

 

[Namlook]

It sounds like you found the problem.

If it was still cutting out then the relay could have been the problem. To verify the problem was the relay, when it was cutting out you could tap on the relay to find it would bring the signal back. This would be either dirty or pitted relay contacts. Some people go through the trouble of taking the cover off and cleaning the contacts. I just replace the relay. If the contacts are pitted then no amount of cleaning will make it right.

9/10 relays that I pull from vintage gear are cleanable and returned to service. After proper cleaning they typically end up with 10 -20 mOhms of contact resistance. I rarely find ones with significant pitting that require replacement. YMMV.

 

[sarris28]

The relay is a reed relay. It is a fujitsu frl-644d024/2as. How can I clean this kind of relay, or what is a replacement I could use?

 

[kwayde]

The relay is a reed relay. It is a fujitsu frl-644d024/2as. How can I clean this kind of relay, or what is a replacement I could use?

That relay can't be cleaned, it can't be disassembled.

You said the problem was gone except for at startup. What happens when you fire it up?

 

[sarris28]

That relay can't be cleaned, it can't be disassembled.

You said the problem was gone except for at startup. What happens when you fire it up?

When I start it up, the left channel does not work, then I turn the speakers off, and max out the volume, I wait for the vu meter meter of the left channel to max out, and I lower the volume and turn the speakers on again. Sometimes, after long listening sessions, the left channel goes out again, and I have to do the same thing again

 

[kwayde]

When I start it up, the left channel does not work, then I turn the speakers off, and max out the volume, I wait for the vu meter meter of the left channel to max out, and I lower the volume and turn the speakers on again. Sometimes, after long listening sessions, the left channel goes out again, and I have to do the same thing again

The relay may not even be the problem.

Best thing to do would be to check for a signal before the relay when you first turn it on. If you have a signal, then the relay is the problem. If there's no signal then you'll have to follow the schematic back to see where it gets lost. This would be the quickest way to rule out the relay and a good way to find the problem.