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Marantz 510M refurbishment?

BmWr75

BmWr75

Top octave? pfffffftttttt
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Marantz 510M refurbishment - do my PSU caps need replacing?

Hey Guys,

I noticed today that the lights on the VU meters dim and the bass sounds a little muddy when I crank the amp to moderately loud levels. Am pretty sure the amp is completely stock based on what the AK seller told me when it was purchased.

Is this an indicator the power supply filter caps needs replacing? Or something else??

Note: the amp is currently plugged into a Monster Power HTS3500, instead of directly into the wall.

Thanks,
Scott
 
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Plug it in the wall and see if that helps... That amp draws huge current at times.
 
Tried it plugged directly into the wall. No change. The VU lamps still dim on big bass notes.
 
It may be normal.... Only way to be sure is to do a power/distortion test with the propper test equipment. If it sounds bad or worse than it used to, it may be time for a tune up.
 
Something simple to do is tack on some caps on the main filter caps just to see if the voltage sag is resolved. I've seen this done on old amps with those gigantic (no longer available) caps on the amp8 site.
 
I ordered these caps from Digikey to replace the PSU filter caps.

Digikey P/N 338-1424-ND CAP ALUM 10000UF 100V SCREW qty. 2

The caps are Cornell Dubilier Electronics part number CGS103U100W4C


Now wish somebody that has replaced the cooling fan with a quieter unit that works well would share where they got it and the part #.
 
Hello,

the lights feed from an extra winding of the xformer. This xformer is able to draw huge amounts of mains power on loud musical pulses. This is normal, has nothing to do with the filter caps. (The filter caps are of computer grade quality, never found a bad one in a 510)
The lighting voltage is not regulated in any way, so flickering is quite normal.
One reason for extensive flickering comes to mind: check and clean the contacts of the soft start relay....

Helmut
 
I had already ordered the caps when @ruesselschorf responded.

Installed the new PSU capacitors today. That was simple, the new caps fit perfectly. Seems like the bass may have tightened up in some, could be the placebo effect though. Need to do some serious listening on some music with which I am familiar.
 
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