Revox A77!!!!!

Hmmmm?:scratch2:

I'll have to look into that. A dbx 224, you say.

Not to argue, but I opened it up and took a peak.
ALPS pots, and the rest of the construction seems reasonably high quality.

But, it was given to me, so it's really no loss, if it is broke.

And you have given me good advice before.

Okay, Thanks Jim, I'll look into it.

Dave
 
New subject : A77 both spool motors locked, what happen?

I recently accquired an A77 (my first one). I was loading a tape, but I found out both spooling wheels were locked. I could not turn them either directions. I also did another test - powering the deck up by swithing to 7 1/2 ips position, block the optical switch light, trigger the guide pin, and then hit the PLAY buttom. I heard the solenoid sound and saw the pressure roller/arm sucked up, but the spool wheels shock a little but not spinning. What happen? what did I miss?
I appreciate any guidence.

Mike
 
I recently accquired an A77 (my first one). I was loading a tape, but I found out both spooling wheels were locked. I could not turn them either directions. I also did another test - powering the deck up by swithing to 7 1/2 ips position, block the optical switch light, trigger the guide pin, and then hit the PLAY buttom. I heard the solenoid sound and saw the pressure roller/arm sucked up, but the spool wheels shock a little but not spinning. What happen? what did I miss?
I appreciate any guidence.

Mike
You say that you could not spin the reels at all by hand? Is that correct? These should be easily spinable by hand, even when the brakes are locked.

If this is correct, then either your motor bearings are frozen, or somebody who doesn't know what they are doing did surgery on this machine, and locked those brakes so tight that the reels wont turn.
 
New subject : A77 both spool motors locked, what happen?

Thanks for looking into it.
I did open the back cover and front panel. I was watching the insde when I turned the spool wheel/motor by hand. I can turn either directions only 2~3 degrees and then stocked. I saw the brake was acting on the motor. What should I do?

Thanks
 
Thanks for looking into it.
I did open the back cover and front panel. I was watching the insde when I turned the spool wheel/motor by hand. I can turn either directions only 2~3 degrees and then stocked. I saw the brake was acting on the motor. What should I do?

Thanks
The brakes should not be capable of locking a spindle like that. Something is seriously wrong with your motors. Does that machine looks rusted-out? The only thing I can think-of that could cease a motor like that is rust.

Although, another possibility is that somebody might have pulled the motors themselves apart at some point, and then put them pack together incorrectly, causing the rotor to rub against the stator, and making it impossible to rotate.

Frankly, I've never seen, or even heard of a similar problem in any Revox before. The AC induction motors these use lack any sort of brushes that could have become disloged that might cause this kind of symptom.
 
2-3 degrees slack is built into the brake pads and films. When rotating the reel plates, the brake films move slightly with them before the break wheels start sliding over the films.

If we don't have a motor problem here, then it has to be a break problem. The reel plates can be removed by undoing the three screws on each. Then the break wheels are clearly visible. The breaks can be manually released by pushing the break lever at the central joint upwards. This should release pressure on the break films and make them loose contact with the break wheels. If this happens and the breaks are released, then the problem isn't with the breaks. If though, the break pads are of the wrong type and they have melted, then they might have joined with the break films and no motion is possible.
 
Hi all,

Brakes are a well known weak spot on ReVox decks. The A 77 Mk I and 2 especially so. All machines should be checked out in this department. Brake Bands are the main failure point. Fine performing machine, easily serviceable. What a ReVox lacks in looks, they return in more ways. P.S. PM me if you have a set of brake bands for an A 77. I need a set for my deck. :tresbon:
 
New subject : A77 both spool motors locked, what happen?

Thanks again for following up.
The deck is almost like new, not a bit of rust, even very litte fine dust. It has no sign or any marks that it has been ever opened or tempered with before. The strange thing is why both motors behave the same.
When I hand turned the motors from the back, I could see the metal belt spring stratch or bend a little but holdiing the motors. Mystery to me.
 
Hi all,

Brakes are a well known weak spot on ReVox decks. The A 77 Mk I and 2 especially so. All machines should be checked out in this department. Brake Bands are the main failure point. Fine performing machine, easily serviceable. What a ReVox lacks in looks, they return in more ways. P.S. PM me if you have a set of brake bands for an A 77. I need a set for my deck. :tresbon:

Check out eBay. I got a whole kit with brake bands, lamps and counter belts from some guy in Italy for around $20.00.
 
Thanks again for following up.
The deck is almost like new, not a bit of rust, even very litte fine dust. It has no sign or any marks that it has been ever opened or tempered with before. The strange thing is why both motors behave the same.
When I hand turned the motors from the back, I could see the metal belt spring stratch or bend a little but holdiing the motors. Mystery to me.

Those flywheels should have some sort of cloth like material on the edges; that's the brake linings. They brakes work by having those metal bands tighten up and squeeze on the flywheels to slow them. If there's no cloth there, you have metal on metal, and that's no good.
 
New subject : A77 both spool motors locked, what happen?

Following Sasi's hint, I removed the front metal disk. I saw the brake film drum was stuck with the cloth rotor, like glued together completely. Then I used the thin letter opener blade to separate the metal film and cloth rotor. Quite slow and hard to separate them. Now eveything is FREE. I guess this deck has been in storage and not been operated for near 30 years. The rotor cloth has been melted and glued with the film drum brake. The deck literaly is new and the heads has almost no wear.
Now everything is resolved. I think I need to clean the inner side of film because it has a residual layer of glue and cloth mixture.

Thanks for all the hints and inputs. Everyone is great and my teacher. Thanks again.

Mike
 
Happy to see that the cause of the problem is found. Now, you need to fix this.

First thing is to clean the steel bands very carefully with alcohol and cotton, clean the break wheels, replace pads and assemble everything.

First option, get a set of A77 break assembly, complete with wheels from the german ebay. Cheap and fastest way to fix this.

Otherwise,

you need to remove the break wheels, by undoing the front axial screws and C clips.

You need to remove the steel break bands by removing two c-clips on each band and carefully removing the spring holding the bands.

Lay the bands on a table with their inner side facing up and carefully wipe them with an alcohol soaked piece of cotton or cotton cloth. Pay extra attention not to bend the bands. Take your time wiping in a single direction.

Then, the wheels need to be cleaned. The old molten lining needs to be completely removed (with sandpaper or schotsbrite sponge, or whatever comes in handy). If they are not replaced, using them with the cleaned bands will again contaminate the bands and show the same symptoms in a few hours of operation.

There is a guy in Italy that sells appropriate pads on ebay. They appear good although a little soft. I may have done something wrong in applying them, but I wasn't happy with performance. I ended up buying wheels with old but good condition lining with perfect results.

Again, the German ebay is a huge source of spares for A77 machines in low prices.
 
ReVox A77 new problem - Take up reel (RHS) spins slow or stop in PLAY

I encountered another problem bothering me and I don't know what to do. May be you have experience on this.
Problem:
Just starting PLAY, the RHS reel turns slow and up so that the tape jumps. Later the RHS turns normal. However sometimes it is worse. When hitting PLAY, the RHS reel drags or stops turning, but the LHS wheel and capstan keep spitting ing tape to the right. Fast forward and F rewind are functioning alright (no slowing down or stop).
1) for testing, I removed RHS brake steel film (to eliminate brake draging issue). Same problem as before.
2) for testing, full tape on the LHS and empty reel on the RHS with no tape threaded thru heads path. Pressing PLAY, the RHS reel starts to spin (c.c.w.) and accellerate up to almost FF speed (somehow I feel is not 100% of FF) with more than a couple of seconds (may be 3~4 sec). The LHS reel spins (c.w.) and picks up speed almost to F Rewind full speed.
The tape path is extremetely clean. The left ideler (rolling bearing) and right ideler(stationary) are also clean.
3) now I thread the tape thru head path. Hit PLAY, the tape jumps and then normal if power up the deck long enough. When cold start, the RHS reel barely moves or even stops.
4) further testing:
LHS full tape and RHS empty reel with no tape threaded. Cold start power up. Hitting PLAY, RHS reel spins up to full speed in 3 sec, but it slows down and stops completely at 6 sec. LHS spins up to full speed and continues.

Strange, isn't it? Any thoughts
Thanks
 
I just purchased a Revox A77. ($362.OO) was the cost of the deck. I just recieved it yesterday and started to play with the unit today, outstanding! I have had the chance to record with the unit.
 
WOW! Talk about a blast from the past! I started this thread three years ago!

Well, just to put in my .02, the Revox is doing fine, I've made about 16 recordings with it and she runs like a dream! I did send it to JMTecharts earlier this year for a rebuild, and it came out great!

ctcapone, Hope you enjoy your newly acquired machine!

Dave
 
What interconnect do you guys use on your A77? The RCA connectors are so close to each other!

Cheers

Kool Kat Jazz Records
 
What interconnect do you guys use on your A77? The RCA connectors are so close to each other!

I needed 12 foot cables to reach my AV receiver and fortunately I had one that fits perfectly, but I don't know what brand it is. I recently bought an Auvio cable from Radio Shack for recording that works, but as you can see, is rather snug.

Wish I can tell you what brand the other is, but it's not marked. Maybe someone can recognize the style?
 

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Revox A77 2track or Revox A77 4track

The Revox are great machines. Very well and simply built, there are very few things that can go wrong. No belts to worry about as they all have direct drive motors.

Which version of the A77 did you get? There were MkI, MkII, MkIII and MkIV. The MkIV are the latest in the series and newest machines that can be found. These are also the more expensive ones as they are newer and (perhaps better) and typically in better condition.

I am afraid that $440 is a bit much for that deck, unless it is in absolutely excellent condition. Also, if it is a "pro" version with high speed (7.5/15ips) and two tracks, because of their semi-pro nature and better sound they also sell slightly more and that can explain the price. Other than that, these decks seem to sell at eBay at prices from $100 to $450, all supposedly in working order.

Did you buy it from eBay? If so, did you buy it from wneigh2222ol8?
If so, then this is a MkIV version, and it may well be worth the money.

There are several things that were improved in these machines, most notably the break mechanism. In the course of the machine's life, one of the "modifications" in the break system was actually a total redesign of it. Comparing pictures of the old break assembly with the new one, it almost appears that the old one was ill-designed - hence the comment from goldear regarding stopping the FF/REW operation before going to PLAY.

The MkIII and forward all had the new version of the break system, which is good. The same designed was carried forward to the B77 and PR99 models.

You can check a number of sites for information about these machines and there are all the relevant service and operation manuals online at studer's ftp, so avoid buying any.

Check out this site in the meantime:
http://www.theimann.com/Analog/A77/Versionen.html


Hello,

I got this two Revox A77 Deck from one amateur recorder who is in his late 60s and was kind enough to give it to me and reasonable price. They are very rarely used, mostly for live recording, may be 500 hrs on each, condition of heads and tape guider are almost like new and have no visible cut on both of them. I have them replaced all electrolytic and those ageing Fracko capacitor, changed belts, lubed all moving pats and planning to put bearing on both side on transport, now both sound awesome. I want to keep one and give up another, would like to know which one should be retained, whether it should be 1) two track for slower speed recording as cross-talk is an issue OR 2) 4 track with higher speed recording as hifi while recording would be a big issue. I want to record my musical, rock as well as classic/ vocals on them from my vinyl. Both has 3 and 7 inch speed. Can anyone advice me on this.

Thank You,
Sach D
 
Revox A77 MK1 -speed issue

Hello,

I have this Revox A77 MK1, replaced all the caps, rifa & all electrolytic, played music and it sounded awesome, but after playing for about 15 to 20 min the speed started to reduce and player does not maintain correct speed. I removed spools put sensor on with some paper insert and played. There I found that the take up motor is rotating slowly. I allowed to cool it down for ten minutes and then started again to find that take up motor is rotating at correct speed now. Put the spool and it was correct speed but again after 15 minutes observed the same problem. Now can anyone help me here?

I suspect it's got to do with those oiled condenser?

Also, after switching off the player one channel speaker gives cracking sound like capacitor discharging, what could be the issue?

I am staying in India and any help would be appreciated.

Thank You for reading!

Sachin Danage
 
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