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Marantz 2325 no power after shorting power amp.

SoundnVision

SoundnVision

New Member
Greetings potential saviours,

I am feeling so many emotions right now. None of them positive. Here's the story.

I had a perfectly good 2325 that I decided to recap as a Christmas present for myself. After about a week of working on it I successfully replaced the caps on all boards (mostly Panasonic FC). At this point it sounded better than ever so I decided to work on the cosmetics. I replaced the faceplate with a new one in black and refinished the wooden case in a dark midnight blue. It looks amazing and I couldn't be happier.

Now here's where things went pear shaped. Before I put the case on I decided to do some adjustments. Started with the voltage regulation and got it set at 35VDC no problem. Then I moved on to the DC offset and adjusted it to zero on both channels. All that was left was the idle current adjustment. I took my multimeter leads and was attaching them to pins J702 and J708 on the right power amp board when all of a sudden one of my leads must have slipped and hit another pin, there was a big spark and then nothing..

The receiver instantly turned off. I unplugged the power cable and checked the fuses. The fuses on the bottom side all look ok. The 200ma fuse on the power supply board was a bit cloudy with the filament still connected but much thinner and darker in the middle. Today I replaced the fuse and still nothing. No power, no lights, no click. I took out the right power amp board and checked for any signs of burnt components but there was no noticeable scorching.

At this point I'm still not over the shock of it all. I was so close to putting it all together and enjoying it for good. I'm definitely not a technician but I'm generally a pretty good trouble shooter and would like to try and fix I myself before sending it off for repairs. Any inputs would be much appreciated, I have the schematics I just don't know where to begin. I really hope it's something minor but fear I may be wrong. This beauty seems to have given up her ghost but I'm dead set on bringing her back. Any help would be greatly appreciated.
 
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did you try powering up with right board removed ? if still no lights on try plugging a lamp or something low power into rear power outlets . see if switched outlet is working ...
i take it you tested the main fuse ?
 
petehall347 said:
did you try powering up with right board removed ? if still no lights on try plugging a lamp or something low power into rear power outlets . see if switched outlet is working ...
i take it you tested the main fuse ?
Click to expand...

Wow.. I'm laughing right now. I completely forgot about the main fuse in the back as I was caught up with my concern for the innards of the machine. Out of site out of mind I guess. Anyway I unscrewed the fuse holder and of course the fuse is burnt to hell. Never have I been happier to see burnt and blackened glass before. What a lovely sight/site. Thank you so much petehall347, you made my day! Now I just need to pick up an 8 amp 125v fuse.
 
not out of the water yet ....
first you need to build a dim bulb tester if you dont already have one ....
something is likely shorted ... output transistors first suspect ...
 
I'll get a replacement fuse, build a dim bulb tester and will report back tomorrow. Assuming I shorted one or more of the transistors, are they still available for the 2325? I know the transistors in my SX-1280 are unobtainable short of taking them out of another unit.
 
Great units!
You may want to make sure the rectifiers are ok. Unplug the power amps before firing up the DBT and see if the lights come on.

Yes they are. The c1116/a747 units are hard to find but if you look at our sponsors including Mouser, digikee, for REAL onsemi Mj21193/94 units, you will do ok. 95/96 work also
 
I must be lucky or something.. All the transistors are ok and the music is filling the room once again! Thanks to everyone here my restoration is finally complete. Fully recapped, lights replaced with LEDs, new relay, new faceplate and a custom finish on the wood case. Did all the adjustments right this time too!

A big thank you to all that offered help in this thread and to this wonderful community in general. I couldn't have done it without all the priceless knowledge spread across these forums. Thank you audiokarma, I feel like I at least owe you guys a picture or two.
Cheers!
:beerchug:

IMG_20170203_202503.jpg IMG_20170203_202520.jpg​
 
Definitely a close call, stroke of luck and lucky escape. Really happy the transistors are all good.

KutzlerTrans said:
Nice unit!
I like the black case.
Is that a sx970 under it?
Click to expand...

Thanks! The case is actually a dark blue, it shows better in the sunlight. I wanted to compliment the black face and blue lights. It was much darker than I was anticipating but it's grown on me a lot since I put it together.

The one on the bottom is a SX-1280, the top left corner of the wooden case is scratched and needs some love but for the most part it's in excellent shape and fully functional. I traded up my Marantz 2285b plus some cash for it and honestly.. If I could go back I wouldn't do it again. The SX-1280 is a beast but I miss the 2285b and should have never let it go.
IMG_20170204_105727.jpg
 
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