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Reading 2325 schematic,newb at this. Learning process.

Thanks Steven. I will look into that. Still in testing stage.
Short update. When i initially plugged it in yesterday and was listening to FM radio. I got a small pop at about 30 seconds in. Another one at around 5 minutes. I could hear the sound kind of fade from left to right channel ever so slightly. So radio has some problems still i think.
So i switch over to tape 1 listening to Cassette. Perfect. Nothing unusual.
This morning back on tape 1cold start, all good.
So i will try FM again and see if i still get pops. Otherwise massive improvement.
Pretty happy, i will invest in a non completely melted light housing from a member here,even though i am quite fond of the leaking light all over the facia. That will clean it up nicely.
Cheers ,will update again when i know more.
 
Be sure to reduce the wattage (current) of the dial lamps if they melted your housing.

The original lamps in most (if not all) of the units with the white plastic housing were 8 volt 190 mA (1.52 watt).

Most of the replacement lamps sold on line etc. are 8 volt 250 mA (2 watt) or even 8 volt 300 mA (2.4 watt), which melt the white plastic housing!!!!!

You can use LED replacements, as they run with almost no heat at all, but they make the color of the dial much more blue than the original lamps.

I use 8 volt 150 mA (1.2 watt) lamps as replacements in any Marantz with the plastic housing (JKL GF660, apparently now obsolete, but I still have almost 100). They are slightly dimmer, but look very nearly the same as the original 190 mA lamps (the difference is not apparent). Of course I replace all the dial and meter lamps at the same time.

The models that have a metal lamp housing can continue to use the 300 mA lamps they came with (or the common 250 mA lamp).
 
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Hi Bob. All lamps were replaced with soft LEDs when i got the amp a year ago. The housing was definitely melted .
Was the original color a greenish color? Right now its a nice blue not the hard blue with the cold led lamps
 
Ya, the original Marantz dial was a warm green color. I have seen many receivers where the original incandescent lamps were replaced with LED's, and they all looked too blue to me. Several customers have had me replace the LED's with incandescent lamps, to bring back the original Marantz look.
 
I posted this picture in another thread the other day. It is a 2230 that was just out of the box in 1972. The color is pretty close, even though it's an old pic. I always thought of the color as teal -- a bit of that blue-green that you see in Caribbean waters. But it's more blue than green. The modern warm white LED's come closest of the LED's, but they do lack that green component.
Marantz1.jpg
 
So i tested my amp again on cold start on FM radio and everything was good. No pops,no noise. hmmm. Will continue testing but there was definitely noise and now its gone.
This is the amp with the soft white leds and you can see how bad the light bleed is. The housing was pretty bad.

SWfECBL.jpg
 
On occasion, when the melt damage is not too great, I have taken a small weller heat gun (used for finding intermittents and heat shrink) to heat the housing, and press the warped parts back into place, but It is not possible on a housing that is severely melted.
 
I remember this housing was pretty bad not only melted but broken in spots.
Upon further testing(FM radio) i got another small pop, sounds like a needle drop at first 30 seconds on power on. And another 40 minutes later. So something in the tuner section. I will try it again on tape 1 and see what happens.
 
So after further testing, (testing only on FM radio). The problem remains, on power up after 5 seconds i get some static,a light pop. I dont get full sound in 1 channel, but after 30 seconds. Everything is good. No more noise no pops. Full sound in both channels. This problem only happens on FM radio. Maybe something in the tuner section,tuner board? I dont know. And how do you troubleshoot for an intermittent problem on a radio? A problem that lasts 1 second at random times usually on cold start. Tape 1 etc are fine. No pops,no noise. all good.
Even if i have to hail mary replace transistors in a section i am game. I would think troubleshooting a tuner is not easy and requires very specialized equipment.
I am open to all thoughts.
Cheers.
 
You can try heating an area of the audio section of the tuner board with a heat gun, and then turn it on to see if the issue is present or not. You can also cool an area after the issue has disappeared, and see if you can get it to return.
 
Thanks Bob. BUT. What signal can you input into an FM board and analyze with a scope? Isnt FM a carrier of the audio band? Or just listen via speakers and see if you get noise?
 
I would just listen with the speakers, and see if you can make the noise appear by cooling components, or make the not appear on cold start by pre heating an area of the circuit.
 
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