|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
99.17.90.152
In Reply to: RE: A700 help needed posted by michael22 on June 10, 2015 at 19:31:20
Both of my A77 machines have gone up in smoke. Since the 'time bomb' or 'firecracker' caps are on the drive board, the first symptom of defective caps is that the tape drive stops. Then billows of smoke come out of the machine. The culprit is usually one particular cap on the motor board (see image). The case cracks and the cap smells. They are usually visually identifiable.
I have successfully replaced all of these caps on both A77 machines, and they work perfectly. So Inmate51's assumption that I don't know what I am doing is wrong. I was simply asking for help to locate the boards in question, as I have never worked on A700 electronics.
I have also completely disassembled the take-up reel mechanism on the A700 to replace what seemed to be a missing washer which was causing the reel table to ride up on its shaft.
And finally, I have entirely rebuilt a Hammond AO-29 amp which required a new transformer, new (substitute) electrolytics, etc.
That said, has no one here worked on an A700?
Follow Ups:
Which version of the A77 went up in smoke? Mk II, Mk III, Mk IV?
Mine is a Mk IV from about 1978-79 or so, and is working fine. Maybe when I sent it up to Steve Smith in Nashville, he replaced those caps and just didn't say anything about it.
With regard to the A700...
The A700 never really made it into the mainstream of Studer Revox decks, which may be why you're having a hard time finding someone who's familiar with servicing it.
I briefly worked with an A700 while I was studying music and audio in Montreux, Switzerland in 1974. I think that's when Studer Revox first introduced the product. It looked very cool, and had an A80 sort of look to the tape transport. I was not impressed with its performance or build quality. We used it maybe three or four times, and went back to our other decks.
Seriously, if you need assistance, Nashville still has some professional Studer techs around - ya just gotta make a few phone calls.
:)
The first to go up in smoke was an A-77-III two-track used by a radio station. I found the cracked 0.47 cap, and replaced it and three others of its type. The machine now works perfectly.When I ordered the replacement caps, I actually bought eight of them, anticipating the same issue on my A-77-IV four-track. This was a machine I purchased new in 1974. Late last year, this machine also went up in smoke. I replaced the four 0.47 caps and it now works fine.
Now I need to replace eight of the 'time bomb' caps in the A700. These are located on the relay board, spooling motor control, and capstan motor control.
I have the service manual, but the instructions on how to find these boards/locations is not clear.
Can someone who has worked on the A700 steer me in the right direction? I will try to make a few phone calls ..
Edits: 07/15/15
"I will try to make a few phone calls .."Finding pro techs in Nashville is easy.
Google "Studer Revox Nashville"
Edits: 07/15/15
Finding pro-techs in Nashville is easy. Getting answers for free is not always easy. That's the idea of these groups. Lee Hazen spent many hours sharing his extensive knowledge helping tape enthusiasts solve their problems (see link below). The amateurs in turn sent their unwanted equipment to Lee as payback. Because of his physical condition, Lee, unfortunately, is unable to continue doing this. I personally always share my experiences - limited to the Ampex A series, Tascam 22-4, and Revox A77 - with fellow tape enthusiasts.
Mine was (emphasis,was) a Mk. IV Dolby.
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: