butternutaud
New Member
I've been searching all over for repair experience/tips on the A700 but have found virtually nothing. Any help or pointers?
Revox A-700 repair tips
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butternutaud
New Member
A700
Hi again,
It does need a lamp which I have on order. The machine will play for somewhere around 15 minutes, slow down and then stop. Doesn't want to start back up. Transport functions all seem to work fine. Perhaps it is a motor capacitor?
When I had my audio store I took it in trade and it has been unused for somewhere around 10 years. I used to do a lot of repairs then but typically another guy would do the R2R's.
What I am trying to do is find out what the typical repairs are and just going ahead and doing them while the machine is up on the bench.
Hi again,
It does need a lamp which I have on order. The machine will play for somewhere around 15 minutes, slow down and then stop. Doesn't want to start back up. Transport functions all seem to work fine. Perhaps it is a motor capacitor?
When I had my audio store I took it in trade and it has been unused for somewhere around 10 years. I used to do a lot of repairs then but typically another guy would do the R2R's.
What I am trying to do is find out what the typical repairs are and just going ahead and doing them while the machine is up on the bench.
Tinman
Super Member
Be careful, the A700 has some IC's in it that are made of umobtanium. Check the big capacitors screwed to the top heatsink for leakage.
The capacitors on the main switch board should be replaced, they are time bombs.
My A700 slowed down as well, it was caused by a bone dry capstan bearing. Oil the capstan motor with a fine machine oil like sewing machine oil, NOT 3-in-1 or anything like it. The A700 needs some special care, you MUST protect those IC's that run it. They CAN be gotten, but the people that have them will rip you a new one for each.
PM me if you want my phone number. There's lot's to discuss on the A700. It's rare, and needs special attention.
The capacitors on the main switch board should be replaced, they are time bombs.
My A700 slowed down as well, it was caused by a bone dry capstan bearing. Oil the capstan motor with a fine machine oil like sewing machine oil, NOT 3-in-1 or anything like it. The A700 needs some special care, you MUST protect those IC's that run it. They CAN be gotten, but the people that have them will rip you a new one for each.
PM me if you want my phone number. There's lot's to discuss on the A700. It's rare, and needs special attention.
Tinman
Super Member
Indeed.... :scratch2:
I've had a rash of the light blue philips caps go dead short on me as well.
butternutaud
New Member
A700 repairs
Thank you very much everyone for your tips! I should be able to get started next week and will get back on results.
Tinman - thanks for your offer!
Regards, Tom
Thank you very much everyone for your tips! I should be able to get started next week and will get back on results.
Tinman - thanks for your offer!
Regards, Tom
A700 problem
Hi,
Just read your listing. Do you know if the capstan shaft is stiff or not. Is the problem control or seizure due to lack of lubrication. If the motor is free to turn, then the problem may be lack of adjustment on the servo PCB. This is the board which is directly behind the 3 speed buttons. there is a test point on the back edge of the board which should be at approx 2.5 volts when the machine has been running stable at 15 IPS for say 1/2 hour. Get this checked out first before any drastic action is attempted. The pot near by should set it up to the correct value.
Hope this helps if you have not sorted it in the mean time.
Hi,
Just read your listing. Do you know if the capstan shaft is stiff or not. Is the problem control or seizure due to lack of lubrication. If the motor is free to turn, then the problem may be lack of adjustment on the servo PCB. This is the board which is directly behind the 3 speed buttons. there is a test point on the back edge of the board which should be at approx 2.5 volts when the machine has been running stable at 15 IPS for say 1/2 hour. Get this checked out first before any drastic action is attempted. The pot near by should set it up to the correct value.
Hope this helps if you have not sorted it in the mean time.
