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Marantz 2285B no sound

Clenxi

Clenxi

Member
Hello,
I recently received a nice marantz 2285B. It is a beautiful and a beast machine, in very good condition. When I plugged it in I noticed a slight HUM coming from the power transformer but it worked perfectly, the relay turned on and the music came. The first thing I did was to recap all the capacitors on the power/protection board, done this I try it, the relay turns on but there is no sound anywhere. It works like a power main amplifier so its evident the problem is in the pre section. It is very strange that it worked without problems before recapping the capacitors and suddenly not anymore, I have looked to see if I had disconnected any cables along the way but no, everything seems to be in order. Any suggestions where I should start looking?
Thanks in advance
 
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In your thread title, it is mentioned as 2285 but in the description, it is 2285B. Which model do you actually have?
 
First, check whether your pre-amp section is getting any power or not, as you already recapped the PS. Check the voltages at pin J809 and J810 on the PS with respect to the ground.
 
The power supply board provides regulated power to the tuner, phono, and pre-amp board. Since you have done the recapping of the PS board any mistakes there can create this problem.
 
sanjib said:
The power supply board provides regulated power to the tuner, phono, and pre-amp board. Since you have done the recapping of the PS board any mistakes there can create this problem.
Click to expand...
Hi, the voltages are extremely low in both pins.
.415v and -1.283.
I check and recheck all capacitors polarity and number, it seems to be all in order.
What should i check next. Thanks
 
Check the voltages on the following pins J807, J808, J809, J810, J811. I guess you said everything was working before recapping the PS. If that is the case then you must have done some mistakes in your work so check your work very well. A nice picture of the PS board will be helpful too.
 
Last edited:
sanjib said:
Check the voltages on the following pins J807, J808, J809, J810, J811. I guess you said everything was working before recapping the PS. If that is the case then you must have done some mistakes in your work so check your work very well. A nice picture of the PS board will be helpful too.
Click to expand...
Hi, after checking and rechecking found an ugly resistor R801, it was open, changed it and the sound comes!! But now i’ve got a hum from speakers also from the headphones. Also have no hum with a phone as a pre.
Will check later but i think the voltage on a j809 i still low. Will check it and post some images.
Thanks @sanjib for guiding me.
 
Clenxi said:
I noticed a slight HUM coming from the power transformer but it worked perfectly,
Click to expand...
This is a different "hum" than what you described earlier... correct? Before you said it came from the power transformer which is a mechanical hum from vibration. This new hum is an electrical audio hum. Does the volume of the hum vary with the volume control setting?
 
Clenxi said:
Hi, after checking and rechecking found an ugly resistor R801, it was open, changed it and the sound comes!! But now i’ve got a hum from speakers also from the headphones. Also have no hum with a phone as a pre.
Will check later but i think the voltage on a j809 i still low. Will check it and post some images.
Thanks @sanjib for guiding me.
Click to expand...
First, make sure everything on the PS is working as it should. Voltages at those five pins should be at the value very near to the values in schematics. After that, if you still have the hum you can work on that.
 
dankik said:
This is a different "hum" than what you described earlier... correct? Before you said it came from the power transformer which is a mechanical hum from vibration. This new hum is an electrical audio hum. Does the volume of the hum vary with the volume control setting?
Click to expand...
Yes this is exactly as you mention @dankik . I mean now there are 2 diffent HUMs, one from the power transformer (mechanical) and one from the speakers, it dont increase with the volume and comes from both channels.
Mention that, the mechanical HUM from power supply doesnt come if I use a dim bulb tester. I think the problem is still in the power board maybe something get hurt with the open resistor i found (R801). Will keep searching today i was too busy this weekend. Thanks
 
sanjib said:
First, make sure everything on the PS is working as it should. Voltages at those five pins should be at the value very near to the values in schematics. After that, if you still have the hum you can work on that.
Click to expand...
Oks @sanjib will do it today and post the results. Hope i can enjoy it again soon. thanks
 
EDIT: Had posted, but reread thread about the main amp working. If the hum is low, maybe it's because the covers are off, try putting the bottom cover back on and see if that's it.
 
rBuckner said:
EDIT: Had posted, but reread thread about the main amp working. If the hum is low, maybe it's because the covers are off, try putting the bottom cover back on and see if that's it.
Click to expand...
Hi @rBuckner already tried puting the bottom cover without luck, maybe can try putting all together, the faceplate included, but i think it will be the same.
 
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