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Marantz 2500 scope help

Ok some progress the p900 board was removed I replaced the 62k 68k and 82k resistors they were all a little high

Replaced the diodes for good measure

Reflowed the board

Cleaned the tube pins and socket

It’s a little better but still pretty dim on the max setting anything else I should try or is this is as good as it will get? My 2110 is much brighter in comparison
 

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Well I once bought a 2110 just to get a better tube. To confirm your 2500 tube is just worn out, swap the 2110 tube into the 2500 and see how it looks. It will likely be much brighter :)
 
That’s a great tip Thankyou

Unfortunately few minutes after I messaged you the amp stopped working played for a few minutes and went bang puff of smoke was so disappointed I had recapped it and done lot of work on it I think transformer will be shot I didn’t dig deep on testing but both rectifiers shorted bit out of my depth now to keep going with it maybe I’ll get to it again one day
 
Very sorry to hear that. If you still want info on your 2500 tube just swap it into your 2110 and see how it looks. If it is still dim, there's your answer. Smoke-bang obviously not good! But your 2500 is very much worth salvaging. Disconnect rectifiers and all transformer connectors and using a dim-bulb tester see if you get a bright bulb. Big blue wire at the soft start resistor is the transformer primary, and the red one at the rear is the other primary wire. Disconnect the rail voltage wiring from the amp module (purple and orange wires on the right side, white and red wires on the left side), and the two little wires at the front of the power supply on the 5-pin wire connector and then you can lift the entire transformer assembly out for further testing. If you confirm the transformer has shorted out, don't give up. There is now available a reproduction 2500/2600 transformer and I have used several and they are an excellent option! Did you redo the main filter caps? Perhaps one of them shorted out. Many posts on restuffing or replacing those caps. Good luck!
 
Thanks for the kind words and advice, I’ll give it a go and see what happens I replaced all the caps but not the filters they were tricky to do was waiting to get it all up and running but your right definitely possible for them to fail…replaced all the zeners, differentials and selected resistors that looked a little hot plus all the trim pots so yeh wasn’t happy when that happened! Hopefully the transformer is ok and just the rectifier and filter caps? Do you think transformer would be ok if it was the filter caps that failed? No fuses blew which I thought was odd! I have a dim bulb tester might give what you said a go with a friend who’s bit more knowledgeable than me thanks so much for your tips it’s appreciated really hope to get it going
 
quadmatrix82 said:
Hi Marantz 2500 experts, hoping to get some guidance on repairing a Marantz 2500 scope, there’s no centre dot and whilst works otherwise the scope display is pretty faint, I tried adjusting the the rear adjustments but not much difference.

AM and FM okay great very strong signal on all stations

Any suggestions on how I should tackle this repair? Thanks!
Click to expand...
Any suggestions on finding a reasonably priced one? They have gone ballistic.
 
Bennett101 said:
Any suggestions on finding a reasonably priced one? They have gone ballistic.
Click to expand...
Scope tube or whole 2500? As an experienced tech and having worked on some 2500/2600 models I advise avoiding the 2500. Piece of junk! Horribly engineered inside and a transformer that may blow up on you. The last high powered Marantz I like is the 2330 (non B).
 
rBuckner said:
Scope tube or whole 2500? As an experienced tech and having worked on some 2500/2600 models I advise avoiding the 2500. Piece of junk! Horribly engineered inside and a transformer that may blow up on you. The last high powered Marantz I like is the 2330 (non B).
Click to expand...
Any 2500 transformer that was going to go has already gone long ago. These units are all 50 years old by now.

2500 is a packed machine, but far from a piece of junk lol.
 
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