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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 24th Nov 2004, 9:19 am   #1
jimbleton
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Default Revox A77 Problem

Ok, so my georgeous, workhorse 1/2 track, high speed A77 suddenly started producing vile smoke for no apparent reason, so i opened it up and had a looksee... At first nothing was evident, so i plugged it back in and tested its functionallity. All seems well except for the annoying fact that it cannot record onto one channel (I believe it is channel II, but could be mistaken) so I have a look inside again, paying extremely close attention to the record amps, checking ALL components both visually and electrically... Nothing seems wrong with them. However, i do spot a leaking capacitor on the relay board... (offhand i could not quote which number, but it is on the edge of the board). As things stand, i have effectively no recording capabilities, and any help would be greatly appriciated
Thanks
J
 
Old 24th Nov 2004, 7:25 pm   #2
Darren-UK
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Default Re: Revox A77 Problem

Hi J,

What do you need help with ? you've answered your own question really, 'that' cap has come to the end of it's life so change it. The A77 is a relatively modern machine, so it may just be one knackered cap or it may have been killed by something else - most likely the former.

The following link may prove useful for service data :-

http://fileshare.eshop.bg/index.php?...archstring=A77

.......or if you browse Ebay there's quite of lot of spares etc for this machine currently listed. Just put 'Revox A77' into a search and you'll find them. Good luck.
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Old 26th Nov 2004, 8:57 am   #3
jimbleton
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Default Re: Revox A77 Problem

You sure that a capacitor on the relay board could affect the recording? Sourcing parts is no prob as i'm a 2nd year elecrtonics student... One outside possibility that's just occoured to me is that if i've been really stupid, it could be that the record head is dirty on just the one channel... but i shall check on all these things when i get the chance
 
Old 26th Nov 2004, 10:52 am   #4
Darren-UK
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Default Re: Revox A77 Problem

Hi J,

No, no, no ......... you've gone off on a tangent here. Your original posting stated the machine 'produced vile smoke' and then you noticed a 'leaking capacitor'. My point was was that this cap has reached the end of its life and therefore needs replacing.

If the machine was ok prior to the smoke appearing, then I hardly think a dirty head is to blame for the concurrent loss of recording ability. As for dirty heads, it's prudent to ensure they're clean at all times and also that they don't need demagnetising.
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Old 7th Jan 2005, 7:24 am   #5
reel-to-reel-man
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Default Re: Revox A77 Problem

Interesting, the cap has been replaced, I had the same fault on my A77. You say it still does not record in one channel? on the bottom inside of the machine you will find all the tape adjustments usually covered over with a paper manufacturers seal, this would be the first port of call I would think. Before damaging the seals you want to have a look on the circuit board for more obvious damage, sometimes the trimmers or surface mount veristors go short due to age and this would produce the problem your having. The easiest way to see if its this is to get some contact cleaner and soak that board in the bottom of the machine then leave for 20 mins before switching on.

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