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Marantz 2325 weak right channel

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xalara76

Active Member
Just got a Marantz 2325 receiver and the left channel sounds perfect while the right channel produces sound but at a much lower level. I’ve cleaned the tape monitor jacks also all of the switches and the relay. It was partially Recapped previously but it was a job that was clearly done by an amateur. My suspicion is that the preamp board will need a recap/transistor. I plugged RCA jacks with my phone into the main in and both amps performed flawlessly, I then put the RCA jacks into the pre-out it was extremely low output.
 
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Good work so far. Sounds like the problem is in the preamp section. The correct way to troubleshoot this from here is to use a signal generator and oscilloscope and go through the circuits to find where the signal is being lost. If you can at least narrow it down to the board that it's on, you could replace all the caps on that board for a start, even if you don't understand electronics. It is most likely a bad cap.
 
dr*audio said:
Good work so far. Sounds like the problem is in the preamp section. The correct way to troubleshoot this from here is to use a signal generator and oscilloscope and go through the circuits to find where the signal is being lost. If you can at least narrow it down to the board that it's on, you could replace all the caps on that board for a start, even if you don't understand electronics. It is most likely a bad cap.
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thank you, I don’t have a signal generator or an oscilloscope, however I think I may roll the dice and buy a little recap kit that they have for the 2325 on eBay it’s about 30 bucks if I remember correctly comes with transistors and various caps. I also clean the pigtail connector that plugs into the preamp with no luck. the tone controls do operate as they are supposed to. If there’s anything else I should check please let me know, do you think anything on the power supply? Again a partial recap there but lots of corrosion. Ive been looking over and over for broken wires. Nothing yet. Could the filter caps be a culprit ? Perhaps a bad ground ?
 
xalara76 said:
thank you, I don’t have a signal generator or an oscilloscope, however I think I may roll the dice and buy a little recap kit that they have for the 2325 on eBay it’s about 30 bucks if I remember correctly comes with transistors and various caps. I also clean the pigtail connector that plugs into the preamp with no luck. the tone controls do operate as they are supposed to. If there’s anything else I should check please let me know, do you think anything on the power supply? Again a partial recap there but lots of corrosion. Ive been looking over and over for broken wires. Nothing yet. Could the filter caps be a culprit ? Perhaps a bad ground ?
Click to expand...
Power supplies usually affect both channels. I would not buy a cap kit on e-bay unless they tell you the manufacturer of the caps. Panasonic, Nichicon caps are good.
 
dr*audio said:
Power supplies usually affect both channels. I would not buy a cap kit on e-bay unless they tell you the manufacturer of the caps. Panasonic, Nichicon caps are good.
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They are indeed nichicon caps.. I have a 2235 lying around that works perfectly. Plugged in RCA's from pre out to main in on the 2325. works beautifully so it is 100% the preamp on the 2325 that is no good. I will start with the recap kit and new transistors for PE01. I hope its not the BA312 IC Chips on that board however, if it is. What is a good replacement for them ? I see that the NTE's are discontinued and the SPARKOS BA312 Chips on eBay are quite pricey at $100. Is there anything else I could look into ? I appreciate your knowledge and input
 
If it was me and I had to replace the BA312, I would buy an adapter board from DIP to SIP and hand wire it to adapt an opamp replacement. You can't just use a straight adapter because there are some pinout differences. Don't use the Sparkos replacement, people are having failures with them. You can check ebay and see if Liberty Electronics or wehavethatitem has the original part. They are reliable sellers.
 
dr*audio said:
If it was me and I had to replace the BA312, I would buy an adapter board from DIP to SIP and hand wire it to adapt an opamp replacement. You can't just use a straight adapter because there are some pinout differences. Don't use the Sparkos replacement, people are having failures with them. You can check ebay and see if Liberty Electronics or wehavethatitem has the original part. They are reliable sellers.
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they really are difficult to find. Im in between this one in the link below https://www.ebay.com/itm/124551407586

or the sparkos replacement. Ive seen many people happy with the sparkos replacements actually. Any idea why some are failing ?
 
Well. I recapped the power supply, added new transistors to it as well. Also recleaned all the switches again for the 5th time. Preamp section still giving me issues. Im starting to question if its on the preamp / tone board now. Also installed the new BA312 chips. That wasnt it either. SOMEONE HELP PLEASE ! Could the “mode” switch cause the issue im having of a weak right channel ?
 
Not the mode switch either. Unit switches between left and right amp and stereo. This is weird ! 100% something in the preamp section. Searched for broken wires too and nothing
 
Check the rca pre amp input and output, on the back of the receiver. Clean them with a brush. If they are dirty, you my have a drop out of a channel or intermittent connection.
 
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