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Fisher X-100 from hell

andy said:
So far it hasn't gotten too hot to touch. I don't expect temperature to be a problem. The materials I used should be significantly more heat resistant that it originally was. The failure I had wasn't caused by overheating, it was definitely water damage.

Today, I replaced one of the crumbling tube sockets along with several out of tolerance resistors. Amazingly, the switches and pots are working fine, and even the power switch is good. There's an obvious high water mark on the chassis. It's definitely not a an amp that should have ever worked again.
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That's great news. On some rusty transformers recently I used loctite naval jelly to dissolve the rust completely, then cleaned and repainted with some semi-gloss black enamel paint. They looked brand new and really improved the look of the restoration. I look forward to seeing what you accomplish next, awesome project.
 
On light surface rust or after brushing, you can use Ospho to convert the rust to a benign black compound and paint over it. I bought a quart of it a few years ago and it is still nearly full. Doesn't take much on transformers.
 
When I took the power transformer apart, I was pleasantly surprised to find very little rust had penetrated between the laminations. A small number had some light rust on which I wire brushed off, and then gave them a very light spray of insulating varnish.

I think the rust on the output transformers is also superficial, so I will probably just brush off the loose rust, and seal it with paint. As long as it's kept dry from now on, it shouldn't get any worse. I'm not too worried about making things look like new. This amp will never win any beauty contests.

I still need to replace one more tube socket which is in the Phono preamp. I've been listening to it, and so far there haven't been any weird noises, or intermittent connections. I've had much cleaner amps that were full of noisy switches, and other intermittent components.
 
I’ve cleaned up some pretty iffy looking transformers including replacing lead out wires and have had good luck.i wouldn’t worry too much. Just give it a go and see what happens.
 
I tested the phono preamp while working on a turntable for a customer. It was basically working, but I noticed some noise on the left channel when adjusting the level. There was a leaky ceramic cap in the phono preamp that was sending DC to the level control. Replacing that fixed the noise. I'll post some pictures as soon as I put the knobs back on. It's not super pretty, but that's fine. It's 100% functional, which is a miracle. Other than rewinding the power transformer, I can't take much credit. It's currently original apart from a couple of tubes, and a few resistors plus a ceramic cap. I'm impressed at how well it held up under adverse conditions. A few resistors were slightly out of tolerance, but not by that much.
 
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