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Help! Revox A77 Noise

K

Kiwibirch

New Member
I've just received a Revox A77 MKIII. (my first R2R) This was shipped to me from
Brisbane to Auckland. The unit was very well packaged however it
appears something has been dislodged in transit or i've just had bad
luck or both.

The deck is making a mechanical noise on playback or recording.
If i ffwd or rewind i don't hear the noise.

I've uploaded a video to demonstrate the issue

https://flic.kr/p/VaRHKv
https://www.flickr.com/photos/kiwibirch/34898458103/


Does anyone have any clues as to what could be causing this?

Any assistance would be greatly appreciated. The deck sounds Amazing, have done a test recording and everything seems to be working. Just have this damn noise which is driving me bonkers :)


<Update>

Noise goes away if i push the front panel just above and left of the tape counter.
Have tried to push the front panel and it seems flush. Still got noise.

Seems to go away when i lay the deck flat.

Seller says that this model didn't have the white counter belt.. Apparently
there were a limited run of these..

Anyone?


cheers

Darrel.
 
Last edited:
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Hi,

Remove the front panel and check for anything fouling the Counter and Counter Drive belt.

The problem is cyclic but not time to either reel rotation.

Cheers.

GPS16
 
Hi,

I removed the front panel and the tape counter appeared to be operating correctly. I removed the tape counter and this is the model without the smaller
white belt it just has gears. With the larger counter belt that goes to the take up reel taken off i.e no longer spinning the counter the noise can still be heard.
So its not the tape counter.

Any further ideas?
 
Hi Darrel,

with the front cover off. Remove the 3 small screws from the reel tables. This will remove them from the brake drums. Check for anything fouling the brake bands. Do NOT touch the bands or the drums. Any grease or oil of any kind will affect the brake operation!!! That includes the grease off your fingers. If any foreign matter is present use tweezers for it's removal.

I have watched the video again. Concentrate on the supply hub.

Cheers.

GPS16
 
GPS16 said:
Hi Darrel,

with the front cover off. Remove the 3 small screws from the reel tables. This will remove them from the brake drums. Check for anything fouling the brake bands. Do NOT touch the bands or the drums. Any grease or oil of any kind will affect the brake operation!!! That includes the grease off your fingers. If any foreign matter is present use tweezers for it's removal.

I have watched the video again. Concentrate on the supply hub.

Cheers.

GPS16
Click to expand...
Hi,

So i removed the reel tables and can't see anything obvious. The brake linings on the drums look good and the bands have a bit of dust on the top of them but nothing
looks like its sticking.

It almost sounds like the noise is behind the reels in the back of the housing maybe? ... its so hard to tell it might just resonate and appear that way.
 
Hi Darrel,

that was the next step. You will now need to remove the guts of the machine from the casing. The motors on these machines have external rotors. Something may have come dislodged during transit and is rubbing the rotor.

Go to
ftp://ftp.studer.ch/Public/Products/
and go to Revox and A77. The service manual is there. It will give information on the correct way to remove the covers. I am familiar with the B77, A700 and C270 machines but not a A77.

Keep us posted.

Cheers.

GPS16
 
Hi,

I had a good long chat with Peter from Nagravox in Australia. Extremely helpful guy. He patiently walked me through some steps to try and isolate the issue.
From this i was able to narrow it down to a brake issue. So tonight i removed the brake band from the supply reel side and cleaned it with IPA. (those bloody c-clips !!..)
The brake band looked clean enough to me but i cleaned it anyway and reassembled. Problem solved !!!!
I'm not sure but i think just removing it and re-seating it might have fixed the root cause. Maybe the band was slightly off or something due to vibration in transit.

Regardless i learnt a lot, had the machine in pieces and back together and silent running :)

Thanks GPS16 for your assistance as well most appreciated.

BTW - I see your from Manchester? I lived there for a year in 91, Chorlton!
Worked at trafford council for a bit. !


cheers!
 
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