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Scott Dorsey Scott Dorsey is offline
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Default Ampex ATR100 operating issues

Gareth Magennis wrote:
I have an Ampex ATR100 here that when you rewind a full reel, the machine
does not brake the supply wheel once the tape runs out.
Leaving a full reel at full velocity flapping about for ages.

Should it do so?


If you put your finger on the righthand tape guide and pull it toward you,
does it stop?

I have read the Service Manual but can't find any reference to what is
supposed to happen when the tape runs out.
This has been reported as a fault with this machine.


When was the tension adjustment last done on this machine? You will need a
scope and a tentelometer... you CANNOT do the adjustment with fish gauges
like you can with the 440. Go through the whole tension procedure and you
will either find that the problem is solved or you will come to a point
where you can't get some adjustment to come in at all.

This is likely the result of one of the tension servo loops having drifted.

The only braking I can see though, is the Emergency braking employed on loss
of power during operation, when the motors spool down by driving a lamp via
a relay opening at power loss.
I can't find these lamps to check them, where are they?


They are 211 lamps, I believe they are under the top cover. I have never
seen one fail, ever. Your problem is not braking, your problem is a servo
slamming full-on.

I have carried out the tension arm checks as stipulated in the manual, they
all check out fine.


Does this include all the servo adjustments or did you just check the arms
with the tentelometer?

What is a bit weird is that with no tape threaded, moving the supply tension
arm past midpoint causes the capstan motor to operate forwards.
I have no idea whether this is normal or not.


That's how it's supposed to work! You move that, the transport thinks there
is too much slack on the supply side, so it moves the capstan forward to
equalize tension between both sides.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."