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Starting up an old Revox A77

T

tsperez

New Member
I searched but couldn't a post about my issue. I purchased the A77 new in 1971 and after my service life hardly used it. The last time I had it on was about 15 years ago. I stored it since that time. I just got it out and cleaned it up. It wasn't too bad since I had it in a room within another room.

My question... do you think it's ok to turn it on after all these years? It was working fine last time I used it. I did turn on a HK Citation 11 preamp that I had stored all that time and it worked! The tone sliders had to be moved for a minute so that they would not sound scratchy.

Thanks in advance.
tsp
Revox A77 - 3 3/4 & 7.5 on 4 tracks.
 
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Very cool having (y)our A77 all that time. You may have heard about the Fraco capacitors in these machines that have a high failure rate. There are three in particular that have been known to smoke. All are on the same board, (the one with the three relays on it). If you don't want to change these out first, the best approach would be to use a variac to bring the deck up to normal operating voltage. There is no guarantee the caps in yours will fail just as there is no guarantee they won't.

There are a couple of other areas that are "fragile" and that should be checked. One of them is the variable resistor on the speed control bd. The wipers on these tend to fail over time. Again, you might have a good experience after just plugging it in and turning it on but this info is to help you prepare for what you might find. Do a search on A77 and no doubt you will find lots of good info to help you prepare for what you may be in for. These are great decks today just as they were back in the day so don't interpret my post as an attempt to smear them or scare you. None of the problems I mentioned are catastrophic. I have four A77s and love them.
 
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Nice! How are you using your tape decks? I have many tapes that are 45 years old! I'll check to see if one still has playable music but I do plan to purchase new tapes assuming everything is in order with my A77. Btw, I still have the "remote" for my A77 plus the Revox head cleaning kit.

Thanks for the advise. If I have to, I'll replace the caps.

tsp


tuttebenne said:
Very cool having our A77 all that time. You may have heard about the Fraco capacitors in these machines that have a high failure rate. There are three in particular that have been known to smoke. All are on the same board, (the one with the three relays on it). If you don't want to change these out first, the best approach would be to use a variac to bring the deck up to normal operating voltage. There is no guarantee the caps in yours will fail just as there is no guarantee they won't.

There are a couple of other areas that are "fragile" and that should be checked. One of them is the variable resistor on the speed control bd. The wipers on these tend to fail over time. Again, you might have a good experience after just plugging it in and turning it on but this info is to help you prepare for what you might find. Do a search on A77 and no doubt you will find lots of good info to help you prepare for what you may be in for. These are great decks today just as they were back in the day so don't interpret my post as an attempt to smear them or scare you. None of the problems I mentioned are catastrophic. I have four A77s and love them.
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There are few Revox tech on AK but, it seems all are now active mostly on Tapeheads.com.
Search for old posts here; you might find they recommend replacing Fraco caps before powering up. My experience, with only one A77, is that I agree; one cap was shot.
For some reason, I think I had four of them, not all on same PC board but my unit is with Dolby so therefore different.

Good luck.
 
tsperez said:
Nice! How are you using your tape decks? I have many tapes that are 45 years old! I'll check to see if one still has playable music but I do plan to purchase new tapes assuming everything is in order with my A77. Btw, I still have the "remote" for my A77 plus the Revox head cleaning kit.

Thanks for the advise. If I have to, I'll replace the caps.

tsp
Click to expand...

I have a high speed half track deck and three 1/4 track "normal speed" decks. I have some prerecorded 1/4 track tapes from the 70s and luckily only one of them has the sticky shed syndrome (an Ampex tape). I buy tape on ebay and record stuff to exchange with my brother who also has decks (a 1/4 track Teac and a half track high speed Teac. We send stuff back and forth since we both share some very similar musical tastes but also have some different ones. Nothing seems to sound as good as tape IMO. We have partnered on a couple of high speed half track "safety copies" of music we really like and they have been incredible - better than CD quality IMO. I am a technician by nature in that I like to fix my own stuff whether its my car, vacuum cleaner, washing machine or audio gear. I know my limitations though and electronics is not my strong suit. I have however chased down every problem my Revoxes ever had and thanks to their well designed, well built quality, they are very friendly to someone who at least knows which end of a soldering iron to hold.
 
I would bring up an A77 on a variac first if it sat THAT long, so you soft start the capacitors.
Problem is that few people have a variac.

You will want to, at the very least, replace the RIFA spark suppression caps on the transport card. The one with the relays. Those tend to crack over time and once air gets to the inside... Poof! Big smoke.

The A77 is so old and so rotten now, I no longer take them for repair. IMHO, it's do it all, or forget it. Most people simply do not want to pay for a complete overhaul, so why bother. A "quick fix" is only going to bite a tech in the ass and ruin reputations. So again, why bother. These decks need ALL the capacitors replaced now.

However, if it's YOUR deck and you can do your own work, they are still worth while to restore. After all, it's YOUR labor, not someone elses.

But once rebuilt, they sound fantastic!
 
tsperez said:
I have many tapes that are 45 years old! I'll check to see if one still has playable music but I do plan to purchase new tapes
Click to expand...
I have 50 + y.o.tapes (factory) that play just PERFECT. Don't know why yours wouldn't - except poor storage conditions.
 
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