Pull the transformers and do a 2 channel push-pull amp? It is a not so clean faceplate. And I know a bugger to recap. Plus all of the other unknown problems. Usually bad volume pots. Then don't have the knowledge, or equipment to re-align the tunerm
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The OEM PIO caps. leak. 😡 Soviet surplus K40 PIO parts make excellent replacements. 🙂 Definitely replace the noisy OEM power diodes with UFnnnn equivalents or (even better) Schottkys.
Long term reliability needs suggest Russian 6П14П-EB (6p14p-ev), AKA EL84M, O/P tubes and a slightly less aggressive operating conditions set.
Even with the cosmetic issues, I'd like to see the unit put into tip/top operating condition. FWIW, I suggest you do most of the restoration work yourself and send the "beast" out to somebody like Mike Samra, for the AM/FM overhaul-realignment. IIRC, 6AQ8s can be replaced by 12AT7s, which reduces dependence on NOS. AFAIK, JJ's 12AT7 functions correctly in RF roles.
Another area of concern is the SS phono section. The germanium BJTs frequently go bad and sourcing exact replacements is difficult. Fortunately, something suitable can be put together using available silicon parts.
Long term reliability needs suggest Russian 6П14П-EB (6p14p-ev), AKA EL84M, O/P tubes and a slightly less aggressive operating conditions set.
Even with the cosmetic issues, I'd like to see the unit put into tip/top operating condition. FWIW, I suggest you do most of the restoration work yourself and send the "beast" out to somebody like Mike Samra, for the AM/FM overhaul-realignment. IIRC, 6AQ8s can be replaced by 12AT7s, which reduces dependence on NOS. AFAIK, JJ's 12AT7 functions correctly in RF roles.
Another area of concern is the SS phono section. The germanium BJTs frequently go bad and sourcing exact replacements is difficult. Fortunately, something suitable can be put together using available silicon parts.
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Yep my Sansui 1000a was sent to Wargo's Electronics. Over a year ago. Still haven't gotten it back yet. Lots of problems with that one. Took forever to get a good replacement volume pot. Then his frequently analyzer was out for repair. Then he started remodeling his shop. One thing after another.
I will do the 500 myself
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I will do the 500 myself
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It's ok I have original McIntosh MC 75's, C20 MR66 front to Klipsh Belle's. And a Dynaco ST70 to the rear Klipsch CF4'S
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If you forego the "contour" feature, replacing the volume control is easy enough. A PEC (Canada) KK series hot molded carbon part sourced from DigiKey does the trick.
If keeping the "contour" feature is a must, hunt down a Noble brand conductive plastic control. The schematic shows 500 Kohms and Michael Percy has 250 Kohm parts on hand. Search the world or make the changes needed for a 250 Kohm part to function well.
If keeping the "contour" feature is a must, hunt down a Noble brand conductive plastic control. The schematic shows 500 Kohms and Michael Percy has 250 Kohm parts on hand. Search the world or make the changes needed for a 250 Kohm part to function well.
Thanks for the heads up Eli. This is not a project that I plan immediately. But in the foreseeable future. Really want to get the 1000a back first, flip it and then do this one myself. I watched a YouTube video of a fellow doing one. He commented, that the FM was aligned with a scope. Which I have.
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Forgot all about this thread. I finished it long ago. Probably around a 6 month project in my spare time. Although FM still has it’s problem, decent reception, stereo indicator bulb only wants to try to illuminate more towards the side carrier while tuning off center of a stronger local signal. Also phone stage, never got completed. My belief is defective transistors on the board. Also was advised unlike the 1000a, it uses silicone instead. Did find some replacements recently, just never got back around to try them.
It took two quads of the Russian 6p14ev to get get 4 close enough to bias within 5%.
I’ve had so many other projects, just pretty much sit this one aside.
Sure has a sweet working aux input though.
I guess the fully rebuilt Fisher 400 got a permanent spot in the workshop instead.
I also treated myself to a pair of McIntosh MC30’s last year. They were still in untouched condition, so rebuilt those and bought a good nos quad GE 6L6GC. Had big stashes of all other 9 pin drivers, cathode followers, phase inverters and rectifiers.
It took two quads of the Russian 6p14ev to get get 4 close enough to bias within 5%.
I’ve had so many other projects, just pretty much sit this one aside.
Sure has a sweet working aux input though.
I guess the fully rebuilt Fisher 400 got a permanent spot in the workshop instead.
I also treated myself to a pair of McIntosh MC30’s last year. They were still in untouched condition, so rebuilt those and bought a good nos quad GE 6L6GC. Had big stashes of all other 9 pin drivers, cathode followers, phase inverters and rectifiers.
