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Marantz 2285B right channel issues

V

Vincent68210

New Member
Hello AKers !

First of all, sorry for my bad English, I'm a French guy looking for some help with my Marantz 2285B ;)

Here is the problem:

In "Phono 1" mode, with my L100 Centurys hooked, I have no sound in the right channel...
The weird thing is that it doesn't do it all the time...

- If I press the "Mono L" button, I have sound on the right channel again, and of course left channel too.
- If I press the "Mono R" button, I have no sound in any speaker.

The Marantz has been completely recapped and the transistors changed some weeks ago, except for the output transistors and the main dual-core filter capacitors.

For information, no problem in FM mode.

Any help will be appreciated, thank you very much! Greetings from France :)
 
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Check the feet screws and make sure they are not too long. If they are they could be interfering / damaging things like the dubbing jacks.
 
Most likely physical issues. Check the selector switch - clean it thoroughly with contact cleaner / Deoxit and exercise it. Also exercise the dubbing jacks if present.
 
ocdecio said:
Most likely physical issues. Check the selector switch - clean it thoroughly with contact cleaner / Deoxit and exercise it. Also exercise the dubbing jacks if present.
Click to expand...
Hmm, it would be surprising that the problem comes from there, because the selectors, pots and buttons of the amp have been deoxidized and cleaned.
 
dankik said:
Does the Phono 2 input work, or is it the same problem as Phono 1?
Click to expand...
I just hooked my TT to Phono 2 and will let you know ;)

EDIT : After more than an hour of listening, the Phono 2 input seems OK. Sound comes out of both speakers with the same volume.

What do you think is the cause of the problem with the Phono 1 input?
 
Last edited:
If Phono 2 is working OK now, then the problem is not with the Phono Amp board since both Phono 1 & Phono 2 go through the same circuit.
Here is the schematic of the selector switch showing the two signal paths for Phono 1 & 2, L & R. After the selector switch the path should be common.
There is a continuity problem somewhere on the Phono 1 (R) input going to the P200 board.
upload_2022-10-26_16-36-42.png

  • Did you Deoxit the contacts on both sides of the 4 wafers on the selector switch? Try it again.
  • Try to clean the Phono 1 RCA jack center conductor (and outer ground as well), if you didn't already do it.
  • Check to make sure that the RCA cable center pin makes contact with the jack conductor on the back of J002.
  • Check the internal wiring from the Phono 1 (R) input jack to J402 connector pin on the P400 board.
 
dankik said:
If Phono 2 is working OK now, then the problem is not with the Phono Amp board since both Phono 1 & Phono 2 go through the same circuit.
Here is the schematic of the selector switch showing the two signal paths for Phono 1 & 2, L & R. After the selector switch the path should be common.
There is a continuity problem somewhere on the Phono 1 (R) input going to the P200 board.
View attachment 2698353

  • Did you Deoxit the contacts on both sides of the 4 wafers on the selector switch? Try it again.
  • Try to clean the Phono 1 RCA jack center conductor (and outer ground as well), if you didn't already do it.
  • Check to make sure that the RCA cable center pin makes contact with the jack conductor on the back of J002.
  • Check the internal wiring from the Phono 1 (R) input jack to J402 connector pin on the P400 board.
Click to expand...
Thank you very much for your answer, I will ask my repairman to take a look at it.

However, are you sure of your schematic?

On my 2285B, which is a European version, the Phono 1 (R) goes to J401 and Phono 1 (L) to J402.
 
Vincent68210 said:
On my 2285B, which is a European version, the Phono 1 (R) goes to J401 and Phono 1 (L) to J402.
Click to expand...
My original schematic was from the U.S. SM. The schematic below is for the Euro version. They are different in the wiring, but it is probably an error in the previous schematic not only in the L/R connector pins but also the swapping of the Phono 2 L & R connector wiring to the switch wafers. Good catch. You can check continuity with your ohm meter to be sure.

upload_2022-10-27_7-25-32.png
 
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