Using it in a not very spacious room, so rather quiet/medium volume listener. Really loved that warm class A sound that PM80 MKII brought.
Phono stage is also important(using MM MP-110 cartridge) so that might leave NAD amps to the background, maybe.
All suggestions are welcome.
Phono stage is also important(using MM MP-110 cartridge) so that might leave NAD amps to the background, maybe.
All suggestions are welcome.
My PM80 MK II works normally for some time, then starts to throw some loud pops and cracks to speakers, probably damaged something inside because of over heating. I was told to not worry about temperature, because it should have some thermal relay inside that switches power off when temps getting too hot. It was used in normal conditions, volume knob to 10 o clock, and it was sitting in TV-table, having about 3-4CM room above.
Wanted to buy another PM80 MKII, but they cost more than PM7001/PM7200, then I started thinking that maybe it is smarter to buy something newer?
Wanted to buy another PM80 MKII, but they cost more than PM7001/PM7200, then I started thinking that maybe it is smarter to buy something newer?
Hi variaator,
I would check for bad solder joints because it was the cause of same problem on a few amps i got for repair.
Bad joints were mostly on power supply boards but also found some around the output transistors/ICs.
Regards,
I would check for bad solder joints because it was the cause of same problem on a few amps i got for repair.
Bad joints were mostly on power supply boards but also found some around the output transistors/ICs.
Regards,
So these in header mentioned amps are **** compared to PM80 MKII?
Power supply board seems okay
Power supply board seems okay
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have multimeter, so got to perform task 5 idling current adjustment and see if I can get same current voltage as it suggests?
That's a good exercise, but your initial complaint seemed to be pops and crackles. You probably want to correct that issue before honing the details. Is the problem isolated to one channel or source, etc? Checks of the the amp output DCV is a good initial place to look.
Listening this amp right now, and the issue is that left channel gets some background pink noise, even when volume knob is turned all the way to 0.
After hour of listening this issue was gone. Trying to run it again today and see what happens.
After hour of listening this issue was gone. Trying to run it again today and see what happens.
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Have a look at the auxiliary power supply behind the front panel. Had the same problem with this amp and the circiut board was simply cooked. All caps on it and some of the resistors were out of spec. Also every solder joint was suspicious. Currently I have it out of the amp again to do a new board for it because it's not made of the best quality material.
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measured from speaker terminals -04.7mV to -10.1mV from left channel, while right channel was roughly half of it
Nothing shabby about those output voltages, but in post 7 picture, I do see some solder joints that look nearly devoid of solder: two arrays of three, oriented vertically, not far from right side screw boss and "W" notch in the sheet metal. Looks to need cleanup and resolder. I'd look carefully for heat damage.
Cleaned it all up from dust, put it to a place where it gets all air from above it needs. Unit works fine now, but will check and measure components from this auxiliary power PCB as many users are finding problematic components from there.
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If you’re seeing low offset at outputs and other issues are resolved, I think you’re done.
Don’t fix it if it’s not broken.
Don’t fix it if it’s not broken.
It is indeed broken. Now the unit is in a state where it produces that pink noise to left speaker all the time like before
Are the pops still present?
Are you able to unplug connector J701 to interrupt audio into power amp? If so, short pins 1 and 2 to ground input to PA and look for improvement versus continuing same issue.
I assume that’s left channel, but did not verify.
Are you able to unplug connector J701 to interrupt audio into power amp? If so, short pins 1 and 2 to ground input to PA and look for improvement versus continuing same issue.
I assume that’s left channel, but did not verify.
If you used this amp in class A mode with only 3-4 cm of space above it, I think it is a small wonder it lasted this long. I used to have the PM-80 SE, so I know what amount of heat these things can produce when operated in class A mode and they had a tendency to break (the Mk. 1, that is). I think I fixed mine three or four times and then I got fed up with it and bought a PM-15S2 LE in 2012.
I wouldn't be surprised that the heat has taken its toll on electrolytic capacitors and solder joints. A discolouration of a PCB is a tell tale sign of heat stress.
You could start with taking a look at the schematic and measure if all the different power supply voltages are still within spec.
Should you choose not to repair but replace: my brother has had the PM-7200 from new (the KI-signature version) and uses it every day. It has never needed repairing, but he does only use it in class AB mode, never in class A mode.
If you can get a PM-15S2 for a reasonable price, then I'd certainly go for it. I think Marantz did a good job on this one and it does have MM/MC phono inputs. By this time Marantz had (IMHO wisely) abandoned class A, though. I don't mind because I was never able to tell the difference between class A and AB, and at normal listening level power outputs, I think you stay within the class A part of AB anyway.
I wouldn't be surprised that the heat has taken its toll on electrolytic capacitors and solder joints. A discolouration of a PCB is a tell tale sign of heat stress.
You could start with taking a look at the schematic and measure if all the different power supply voltages are still within spec.
Should you choose not to repair but replace: my brother has had the PM-7200 from new (the KI-signature version) and uses it every day. It has never needed repairing, but he does only use it in class AB mode, never in class A mode.
If you can get a PM-15S2 for a reasonable price, then I'd certainly go for it. I think Marantz did a good job on this one and it does have MM/MC phono inputs. By this time Marantz had (IMHO wisely) abandoned class A, though. I don't mind because I was never able to tell the difference between class A and AB, and at normal listening level power outputs, I think you stay within the class A part of AB anyway.