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Ampex ATR 700 - Help needed

S

SFM-Ptgal

Here's another plea for help. I have an ATR 700. Seems ok except: It doesn't rewind.
When I press on the rew button It doesn't make anything. I can't ear any relay, like on the other keys. If I use the remote on the back it's the same: nothing. So it's not a keyboard issue.
I don't know if this is a typical fault from that machine model.
I have the owners manual. But I need an advice to know where to start from, as far as I remember the issues fluxogram isn't explicit regarding this issue (I don't have it with me now)

Thank's for your help.

Pedro
 
Check first to see if the rewind switch is making contact. Unlikely, but not impossible for a switch to fail. If the switch shows good contact (you can check with an ohmmeter with the power off) and you can't hear the relay clicking, then it's likely the relay. Although there may be an intervening transistor or IC driving the relay. Been a long time since I've worked on that model. (if there is circuitry driving the relay, you can probably also troubleshoot that with a VOM--probably use a collector pull-down to take the bottom of the relay coil to ground to pull the relay in).

But my bet is on the relay--either a bad coil or the diode shunting the coil gone bad.

If the relay clicks (try rolling up some stiff paper into a cone and putting the point on the relay case like a stethoscope--makes it easier to hear)--then the contacts might be burnt. Another possibility if the relay pulls in and no action--find and look at the resistor that is switched in or out going to the rewind motor. That may be open. Be careful there--believe there is a fair amount of voltage at that point.
 
Those machines were apparently notorious for transport button wear and tear. I bought a well used ATR-700 from the first station I worked at and had to build a remote button panel for it, as the front panel buttons were worn completely out. I had the buttons' contacts cleaned up and resoldered on the machine, but the rewind button was the only button that didn't work perfectly (it became intermittent in operation).

I've had a couple of friends own the same model as well; same issue with the buttons.

That particular unit had alot of Teac brand parts and circuitry in it. The transport motors had Teac stamped on them from what I remember.

Good machine, if you can get it to behave. I loved mine; wish I didn't part with it.

I'd love to pick up a Tascam BR20 one of these days.

-mattthepm
 
Its been years since I've worked on one of those. A station I was at had 4 of them. I never had a rew problem but I did have a play problem and it was a relay (if I remember correctly - lot of cobwebs to jar loose).

The biggest problem I remember was with head allignment - they were a bear. The trick I used to allign was to do it and then wait a day and check it again - use lots of nail polish on the lock screws.
 
Used to have one of those machines myself. I never had any problems with control buttons. But discovering the line inputs were unbalanced, was a pain. Once I got that solved, it served me well while I owned it.

I never cared much for Teac's reel hub holders. They wore out pretty fast. I finally got mine modified with Otari style hubs like the 5050BII model, to fix that issue.

R
 
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