2500 from beyond the realms of death

[Salbreth1]

Man that's a mess. I have one if you need info/pics.
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Much appreciated, but you might regret saying that! :yes:

Lord God Billy Bob!

Did the tech go insane, or the shop owner?

He told me the tech went crazy working on it for months. The owner came in one day and it was completely disassembled. Unless this thing was getting a new chassis, I don't understand it.

If you buy it, also obtain the right to come back to the shop and prowl around to find missing parts.

Chip

Lol, I do! God forbid there is a missing part that renders this thing useless. He does still have the knobs, I'm waiting for a call to pick them up.


So, I disconnected everything but the filters and rectifiers and Whoo! 90v rails! It looked like a bad science experiment in the basement, and no, the treadmill is not my bench Now I can bring it up stairs.

I also checked the outputs. FYI they are soldered in. I almost learned that the hard way... But the joints were original and so must be the transistors. No shorts, they all read between .450v and .500v Things are looking good so far.

Time to order parts!

 

[bktheking]

Outputs should be socketed unless someone soldered them to the sockets.


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[catrafter]

Hmm, every 2500 I have worked on had the base and emitter leads of the outputs soldered into eyelets that were in turn soldered to the circuit board, no sockets. To get them out took some work with a Hakko 808.

Tom

 

[Salbreth1]

Yup, no sockets. I checked them in place. Base and emitter are soldered to the pcb.

 

[blhagstrom]

I have one of Sam's open here.
Soldered in outputs. Exactly as shown above.

I'm taking reference photos while I'm in there. The back of the unit is probably not going to be touch to connect back up. Maybe up in the packed stuff in front.

 

[bryans12v]

Yup all soldered to the collector board. This is from a 510 but very similar tunnel/output arrangement.



The fun part is soldering them back in making sure both top and bottom pads have good, even coverage.

 

[nj pheonix]

 

[blhagstrom]

Some reference photos from one I just fixed.

 

[blhagstrom]

More reference

 

[blhagstrom]

More

 

[blhagstrom]

And more

I have another one to get into and may have to go deeper. There is a distortion in one channel. If there are other angles of wiring connections available, I snag them too.

 

[Salbreth1]

And more

I have another one to get into and may have to go deeper. There is a distortion in one channel. If there are other angles of wiring connections available, I snag them too.

Thank you! These pictures are gold. There are a lot of spade connections that I haven't identified yet, honestly I haven't looked at all to see what goes where yet. I printed the schematic and scaled it to fit on 4 pieces of paper taped together, but pictures much easier[emoji1]

 

[trikster]

I know its a basket case, but that unit is dead sexy. This will be a labor of love that I hope will be handed down to your 10-month old when he or she is an adult. Good luck with the project. I am watching with interest and am cheering you on in this project.

 

[KutzlerTrans]

Thats crazy Sal, one thing at a time. That is a heck of a project your taking on. Looks like you have some excellent support here:thmbsp:

 

[don philipe]

Piece of cake.You should have that thing up and singing in a day or two.

 

[rBuckner]

I'll be home in a few days and can offer photos as required. I have more than what I posted in my rebuild thread. I really appreciate that you're bringing a rare bird back to life. See, I assume your skilled efforts are going to be successful! :yes:

I agree with tx on the tuner, hoping yours is okay. Any extra volume knobs are worth way more than gold!

 

[bktheking]

Wow . First time I've seen the outputs soldered to the board. I didn't have to change them in mine, they were already swapped. I guess Marantz figured they would never go bad! I stand corrected. Thanks for posting pics.


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[blhagstrom]

Wow . First time I've seen the outputs soldered to the board. I didn't have to change them in mine, they were already swapped. I guess Marantz figured they would never go bad! I stand corrected. Thanks for posting pics.


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The Vintage Crown amps are soldered in also. The DC300 was popular with bands for concerts but then Carver came out with the 700 Phase Linear.
Techs liked them better because the outputs were socketed. Quick fix.
The original 700 didn't have enough heat sink, so running them hard for a concert overheated them. Thus the term Flame Linear.

I had to remove the outputs in the second 2500 I working on here.
It sucks. Tough to remove and tricky getting back in. They are hard to get all the solder solder sucked out.

Oh, and Bose 1800 and 1801 are all soldered in too.

 

[bktheking]

I've worked on crowns too, I know those are soldered. I thought it was more for road amps than high end receivers.


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[blhagstrom]

I've worked on crowns too, I know those are soldered. I thought it was more for road amps than high end receivers.


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I've seen it on much smaller units too. Some of them a royal pain to even get at and a real pain to remove for testing.

The Marantz 500 has sockets (at least the one here) and the socket is tubes sticking up from the board but below the heat sink. They are a real pain to get in. Hard to see and tricky to hit. Quite a surprise for such a nice amp.