Anybody ever recap their A77/B77's?

[turnturnturn]

I ask because it seems to be a reasonable thing to do with '70s gear, but I haven't found anything on the 'net after some admittedly half-ass searching, at least with regards to Revox R2Rs. Is it difficult to swap out caps in PS, audio and other circuits on these machines? Tight fit, maybe? Obviously I don't own one--yet.

--Alan

[Pentium100]

I have replaced one capacitor in my A77 - it was shorted.

As for others - most of the capacitors can be replaced easily - they are on removable cards, like in a PC. PSU and capstan motor boards can be more difficult to remove but possible. The hardest is the "motherboard" where the input/record/play amps are plugged in. But it only has two capacitors. One of which was bad in my tape deck. But I cheated - since that capacitor was axial (looks like a big resistor), I just cut off the leads and soldered a regular (radial) capacitor on them, so I did not need to take the "motherboard" out.

A lot of capacitors there are axial (probably all the big ones). I don't know about stores where you live, but I can only get radial capacitors (where both leads come out from one end), so it may be a problem if a big capacitor fails because I will need to somehow make a radial capacitor fit there (smaller ones are easy, bigger ones are not).

[Skywavebe]

Hi Alan,
It is good to recap many older items of the 70's or 80's era but there are some types of equipment that stand above the rest with regard to the parts used and quality of construction. I don't have a lot of experience with these models directly but if I had one to deal with, I would consult one of our members here that has had a lot of experience with that model and that would be Leon Ament. He is in Canada, but don't let that stop you as he has a lot of good ideas and knowledge- I would let him say what his experience is in this matter.

[turnturnturn]

Thanks for you answers, Pentium 100 and Sam.

I understand that willy-nilly recapping could have deleterious effects on the sound of the deck, and I want to avoid that. Then again, there's nothing wrong with experimenting and reporting on what you find, which is something I might end up doing. I'm about to recap a Superphon Revelation Basic preamp from the '80s, and I'll be using Elna Silmics, not the Black Gates that the original designer, Stan Warren, suggested. BG's are not easy to come by in the sizes I need any more. I suspect that I'll hear an improvement over the stock somewhat-better-than-average caps that are already on the power and signal boards.

But I'll take your advice and take my time, Sam, as far as "upgrading" any Revox-es that might cross my path in the near future. And I'll certainly pay attention to what Leon has to say.

Thanks again.

[Kent T]

The Frako electrolytic capacitors and the Blue Philips capacitors should be replaced on all A 77 decks. Both are beyond their prime and sonics suffer on these decks until it is done. Also, these caps on some boards going bad cause many a glitch on these decks.