Just got a 2325 and its a MONSTER RECEIVER ! Unfortunately its having some weird issues. Relay will engage 9/10 times but no sound just a weird hum almost background noise that doesnt change with volume adjustment. Plugged phone into dubbing out jack and I got sound on both channels but it sounded garbled. Meters are responsive for AM/FM operation. Relay will also disengage randomly at times. DC offset is set to 35V but bias on amp boards arent able to be adjusted to “0” and are at 58.5V DC. What gives? Im thinking its something in the power supply section ? I also checked on the PS board that the fuse was replaced at a point. It calls for a 250V 200mA fuse but it was replaced with a 250V 1/4 fuse... could this be the problem as well ? Thanks in advance
Marantz 2325.. weird relay clicks.. bias adjustment wacky..
- Thread starter xalara76
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There are three adjustments to check:
Bias (idle current), measured most easily at the resistor next to the bias trimmer: 15mV
DC offset, measured at the speaker terminals: As close to 0.00mV as possible
Power supply DC output, measured at J805: 35VDC
DC offset is of particular interest, because if out of adjustment far enough it can cause the relay to open.
The 250V 1/4A fuse on the power supply is fine.
Relays open intermittently for 3 reasons, in this order of frequency:
Bias (idle current), measured most easily at the resistor next to the bias trimmer: 15mV
DC offset, measured at the speaker terminals: As close to 0.00mV as possible
Power supply DC output, measured at J805: 35VDC
DC offset is of particular interest, because if out of adjustment far enough it can cause the relay to open.
The 250V 1/4A fuse on the power supply is fine.
Relays open intermittently for 3 reasons, in this order of frequency:
- One or both amplifiers are putting out excess DC. The protection circuit opens the relay.
- The protection circuit is failing.
- The relay is failing.
First of all either your measurements are not correct or you want to mean something else. DC offset should not be 35V it should be 0V. Did you mean power supply voltage setting between pins J804 and J805? The bias should not be set at 0V it should be 15 mv. The voltage you measured (58.5V) can not be the bias. My advice first to disconnect both amp modules and check whether the relay is clicking normally or not. I think you measured the power supply voltage (35V) and seems to be fine.
Yes correct so J805 is 35v DC. Plugged DMM into speaker terminals and went to adjust the dc offset to 0.00mV but it wont adjust and is simply reading 58.5
Yes J805 is 35V but the Dc offset on the amp boards measured from the speaker terminals is at 58.5V DC. Will try disconnecting the amp boards like you said to see the function of the relay.
After taking out the amp boards, check the output transistors and all driver transistors on your both amp boards. Do you have a dim bulb tester?
I’ll take it apart on Monday to test the output transistors. Ordered a full recap kit for the PS and amp boards which included transistors and diodes as well.
will do more testing and report back. I also noticed that near the power button it has a “heat” smell to it. Looks original but when powering the unit on and once the relay clicks I get an audible pop through the headphones and the same pop when it gets turned off.
Also wanted to mention ive tried rca to both main in and pre out and got nothing. Plugged headphones into dubbing out and the music was playing but sounded very distorted
1. Did you get this result on both left and right amplifiers? I'm not sure how 58.5VDC is getting past the protection circuit and relay. To test DC offset:
- There needs to be no input and the volume control full counterclockwise.
- Use trimmer R713 to adjust the DC offset.
- The final measurement will be in millivolts (mV), not volts.
- Setting it to 0.0mV requires fine adjustment of the trimmer and zen like patience.
3. Making a DBT is important. You can google "dim bulb tester images" to see many different ways to put one together. A DBT may save fuses and component damage while you work on your 2325. You'll need a 100W or higher incandescent light bulb. The 100W will work, but for the 2325 a 125W or 150W is the best choice if possible.
4. The advice to not start changing parts is good.
Great info.
It was brought to a shop and this is the info I was given. Sounds like he was about to just recap and rebuild the whole thing almost which is what I plan on doing. Now what it means bu complete rebuild is he including output transistors? Im going to have to take them apart and test individually. If they are problematic then what are the proper pnp and npn replacements for this 2325 ?
