Hello.
Marantz PM 310 low volume output...
50%.....
The sound is very good,no distortion .
Bias ok,11mV.
All voltages are OK.
33V....-33V...15V.....-33V.... OK
No blown fuses...No damaged parts.
Amplifier works fine but volume is 40....50 % lowest.
If I activate loudness knob no change.
SM
https://www.google.com/url?sa=t&sou...QQFnoECAUQAQ&usg=AOvVaw1x4QOCQl2EhUSCBuZ9FiRc
Marantz PM 310 low volume output...
50%.....
The sound is very good,no distortion .
Bias ok,11mV.
All voltages are OK.
33V....-33V...15V.....-33V.... OK
No blown fuses...No damaged parts.
Amplifier works fine but volume is 40....50 % lowest.
If I activate loudness knob no change.
SM
https://www.google.com/url?sa=t&sou...QQFnoECAUQAQ&usg=AOvVaw1x4QOCQl2EhUSCBuZ9FiRc
Last edited:
Does the headphone jack work ok? Does the tape monitor switch work?
Does this happen on more than one source?
Does this happen on more than one source?
Last edited:
Headphones Jack ok but low volume
TAPE monitor switch work fine
All sources same level
TAPE monitor switch work fine
All sources same level
Last edited:
Ok, first please answer these questions:
What sources do you have, turntable, tuner, tape, CD, etc?
Do you have another working receiver to use for a test?
What test equipment do you have, digital voltmeter, scope, probes, etc?
What experience do you have working on electronics?
What sources do you have, turntable, tuner, tape, CD, etc?
Do you have another working receiver to use for a test?
What test equipment do you have, digital voltmeter, scope, probes, etc?
What experience do you have working on electronics?
I have cd player, turntable ,tuner and working reciver.
I have a Digital voltmeter , electronic parts tester and Audio signal tester.
My electronic experience is basic
I have a Digital voltmeter , electronic parts tester and Audio signal tester.
My electronic experience is basic
Ok, first use the exact same CD player to play through your other receiver.
Verify that the sound level seems normal, not like with the other receiver.
What is the audio signal tester you have? No scope?
Verify that the sound level seems normal, not like with the other receiver.
What is the audio signal tester you have? No scope?
Now that I look more closely at the schematic, there is a muting circuit located
just after the volume control, and just before the input of the power amplifier section.
With the CD player connected and playing, but with the receiver volume set at minimum,
check the signal at the "top" or input of each section of the volume control.
It should be at about the same level as the CD player's output at the RCA input sockets.
I think the muting circuit is bad, and is constantly cutting off the input signals.
The simplest way to fix the problem is to defeat the muting circuit, by lifting one end
of the diode QN06. If that works, later you can try to fix the muting circuit, but that
will be much more difficult.
just after the volume control, and just before the input of the power amplifier section.
With the CD player connected and playing, but with the receiver volume set at minimum,
check the signal at the "top" or input of each section of the volume control.
It should be at about the same level as the CD player's output at the RCA input sockets.
I think the muting circuit is bad, and is constantly cutting off the input signals.
The simplest way to fix the problem is to defeat the muting circuit, by lifting one end
of the diode QN06. If that works, later you can try to fix the muting circuit, but that
will be much more difficult.
Last edited:
Ok, it appears that this diode must have a positive voltage to unmute the audio.
Solder back the QN06 diode.
What is the DC voltage at the band end of diode QN07, with respect to ground?
Also what is the DC voltage at the other end of the diode, with respect to ground?
It appears there is a typo in the schematic. The QN07 diode voltage is listed as 82VDC,
but it should be 32VDC instead.
Next, what is the DC voltage at the band end of diode QN03, with respect to ground?
Also what is the DC voltage at the other end of the diode, with respect to ground?
Should be 32VDC.
Solder back the QN06 diode.
What is the DC voltage at the band end of diode QN07, with respect to ground?
Also what is the DC voltage at the other end of the diode, with respect to ground?
It appears there is a typo in the schematic. The QN07 diode voltage is listed as 82VDC,
but it should be 32VDC instead.
Next, what is the DC voltage at the band end of diode QN03, with respect to ground?
Also what is the DC voltage at the other end of the diode, with respect to ground?
Should be 32VDC.
Last edited: