Got me a rusty old Marantz model 8 to restore

I am very much considering that route, but this blog has me at least wanting to try.

http://getinthewoodchipper.com/?p=430

I think as long as I get it out and inspect it if I don't see any problems at least I'll know I did all I could myself. I know if I had to get it rewound I would always be wondering if the sound signature has been altered.
I saw that same blog when I had a bad citation II transformer, I was going to try it, but decided against it,If I damaged it, possibly it couldn't be rewound properly by the next person. I bought another "good" one on the auction site, and sold the bad one. Net cost was $130, problem solved.
 
Very stinky and messy job, with the release of potentially toxic fumes, and very low success rate. I would tend to agree with the above members and send it to a transformer specialist. Still, one problem remains: is there such a transformer "expert" somewhere who can rebuilt it to the original Marantz specs (which are unknow) considering the fact that this is a very special transformer and the winding datas were never published and original materials used no longer available ? I have serious doubts about it. Even if these informations would be available it's still an expert job very few can do. (and certainly not for 200$ !) Sure, it can be rewound and will work (more or less, maybe with some stability issues) but your amp will never be a Marantz again, and yes: the sound signature could be altered. Maybe this is the only (good) reason for trying to salvage the original transformer, and you have nothing to loose. (but your time)

If it were me, it's simple enough. See if the transformer guy can un-pot the transformer and find and fix the problem without necessarily rewinding it. In any case, it'll be worth the $200+.
 
all good advice guys and I am weighing the options. Obviously if I could find a replacement 8 trans that would be a no brainer. I haven't seen such an endangered specimen anywhere.
 
Very stinky and messy job, with the release of potentially toxic fumes, and very low success rate. I would tend to agree with the above members and send it to a transformer specialist. Still, one problem remains: is there such a transformer "expert" somewhere who can rebuilt it to the original Marantz specs (which are unknow) considering the fact that this is a very special transformer and the winding datas were never published and original materials used no longer available ? I have serious doubts about it. Even if these informations would be available it's still an expert job very few can do. (and certainly not for 200$ !) Sure, it can be rewound and will work (more or less, maybe with some stability issues) but your amp will never be a Marantz again, and yes: the sound signature could be altered. Maybe this is the only (good) reason for trying to salvage the original transformer, and you have nothing to loose. (but your time)

It is a terrible job. I have done it with a 50% success rate on Marantz, Quad II and Citation power transformer. It can be done. I also agree that I cannot see how $200 will get you there.. I know for a fact that Doc Hoyer has the specification prints from Marantz and he has done one for me. Its not a $200 job. The toxic nature of it all can be avoided if you do this outside. I used my bbq and a metal pan.

You have little to lose if you can slide it out and look for the obvious; otherwise its find a good core somewhere else or send it for a rewind or park it until a core comes up- I have seen a few pop up in the last ten years rare but "possible".
 
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If you decide on a new transformer it might be good to replace the output transformers in both channels . I fear it might be hard to balance the sound if the channels have even slightly different transformer. Others with more knowledge than me might think otherwise.
 
That is exactly how I was thinking of doing it kcin, no way I would ever try this in the house, I would be single after that!

Game plan is to go slow and if I run into any sort of problems or if it starts going in the wrong direction that will be the end of it and I will reassess my options.

Like I have said, I am bringing back this wreck of a Marantz 8 because the wealth of knowledge I am learning is as valuable, if not more, than the amp it's self. If I can successfully pull this off I will be one proud camper knowing that I did it my self. The way it is shorting out kind of makes me believe it is at one of the terminals for the primary taps, of course I could be wrong on this, but you never know until you try.

Going to take a few days of brainstorming and googling before I pull it off, but you can bet all of you will be along for the ride!

Damn, gonna have to wreck my nice paint job!
 
It is not that difficult to unpot a transformer. And yes, I can rewind these transformers for $210.00 plus shipping.
Turns, wire size, layers are all counted and what comes out, goes back in. What you have to be careful of is these transformers are bifiliar wound and you need to pay attention when taking data, not for the faint of heart. Yes, there is two primarys and three secondarys. If you have not wound a transformer before, this one is not the transformer to cut your teeth on. I also do testing on these transformers. AC voltge tests, c hi-pot tests, PI tests and a ringing test. .
Thank you,
TRS
Gary
 
It is not that difficult to unpot a transformer. And yes, I can rewind these transformers for $210.00 plus shipping.
Turns, wire size, layers are all counted and what comes out, goes back in. What you have to be careful of is these transformers are bifiliar wound and you need to pay attention when taking data, not for the faint of heart. Yes, there is two primarys and three secondarys. If you have not wound a transformer before, this one is not the transformer to cut your teeth on. I also do testing on these transformers. AC voltge tests, c hi-pot tests, PI tests and a ringing test. .
Thank you,
TRS
Gary

Well that's a bargain then. The original poster has good options. Thanks.
 
The best of luck. I hope Gary finds a broken lead at the surface and it doesn't need rewinding. In any case, pictures of the process would be fantastic!
 
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Gary received the OPT yesterday and quickly tested it out..

"I applied 30vac to one side of primary and watched the current draw jump back and fourth from 500 mils to 8 amps. It is shorted."

So suspicions are confirmed, it is definitely shorted. We will see what he finds when he opens it up. Glad we have an answer, and can't wait to get it back and get this old girl making sweet music.
 
Hey guys, still here! Gary has been busy as of late so still waiting for the transformer to be finished. You can bet that I will post results as soon as I get it back. I can't wait either!
 
Nice write up! How'd it go?

I'm starting on a 8 and 7 :confused::eek:o_O:crazy:

Would love to see your works in progress! Lots of incredibly knowledgeable folks around here to keep you on the right direction.

EDIT: Just having a gander at your rebuild thread right now, great stuff!
 
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