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Marantz 4300 weak rear right channel

daveyh

daveyh

Super Member
I have a Marantz 4300 that I can not for the life of me find out why the right rear channel is weak. I rebuilt the power supply and the voltage is at 35v. I rebuilt the tone board with new caps and transistors as well as the buffer/preamp board, the phono board, the Matrix board and put in two new 48v speaker relays.

I also cleaned all the switches and pots including the local/remote and the 2/4 x switch in back more than once. Still I have very little volume in the rear right speaker. I changed speakers and still the same. The amp boards work fine in stereo. I have pulled and checked the outputs and the 2sc627 transistors. I have not replaced the four 35v 220 caps in the amp boards. The outputs are Sanken on the right side and the original Marantz outputs on the left.

Can some shed some light on this? Anyone know what the problem might be? I am going to replace the four 35v 220uf caps in the amp boards and have them on order. Do not know if that will help or not.
 
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KutzlerTrans said:
Did you clean the RCA Jacks/jumpers twix the R/R.
Click to expand...

Try cleaning them. Did not help.

I did notice that it even has a weak right channel in REMOTE speaker section.

I should also point out it was doing this prior to me working on it and I can not get a strong right channel with my headphones on either.
 
try crisscrossing your pre/main amp rca's with phono jumpers and see if the problem remains on the same side or if changes.
If the problem goes to the other side, you may have a pre amp issue, or dirty connections at the pre amp connector.
If the issue remains on the same side, You can swap amps from side to side to verify it.
Then you will know what path you are going to take. Plenty of smart guys on here that can rebuild your amps if needed. Were are you located??
 
I did what you suggested and it still had a weak channel on the RR. I recently rebuilt the pre-amp board and had done that once already but I guess I did not check it that way again. I been working on this thing for 4 days. :boring:

I used my DMM to checked the voltages and signal tracer and to trace it down one more time and pulled the board. This time I looked real close on the board using a large magnifying glass where it had lost sound on the component. I has a very very small broken trace I could not see without a magnifying glass. I scraped the trace and soldered it and now it works!!!

Thanks for leading me down the correct path. :thumbsup: It was driving me crazy.
 
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