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Help with Tek 2430A

Hey everyone.

I've got a 2430a with an issue. When I first start the scope up and
perform some measurements the trace and everything else drifts. The
trigger level will slowly drift up/down without me touching any
controls, I can watch it over a few minutes and it will drift a couple
of volts. The trace drifts. The controls dont like to respond to
inputs, sometimes I have to push a button or turn a knob 2 or three
times for the scope to react, other times it will go on the first
try. When I change the V/Div of the scope the trace will shift up or
down, sometimes completely off the screen.

Now the interesting part is that if I perform a self cal the scope
works perfectly, no drift and the controls work perfectly. I do
believe that a self cal in not normally required after every start-up,
so I assumed that the battery was going bad or already bad. When I
opened the scope up to check it I found that there was none! There is
just a jumper in it's place and the associated components like the
diode and IC aren't there either. Not missing just never installed,
like there was a board revision. The service manual shows plain as
day the battery in the schematic and makes mention of proper disposal
of it in the first chapter. I've looked and looked for another
service manual, thinking there might be another version, but only
found the same one that I already have.

A few random tidbits that may help. Self cal always says UNCALD after
start up, but passes with no problems. External cal says UNCALD. The
manual mentions ready and arm leds, which don't seem to exist on my
scope. Manufacture date is 1988 with the last software update in
1990.

I think that's it, if you can offer any advice at all I would
appreciate it, I've kind of hit a wall on this one, without a accurate
manual I can't really do much. All I can do is guess there is a
problem with the memory wich is a pretty broad statement. Anyway
thanks for any advice you might be able to give.
 
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