Re: TEK 7704A pre-death behaviour a clue to the fault?


Eric
 

First thing I would suspect is a leaky electrolytic or a tant that is
shorted. I am leaning more to the electrolytic though. Seems like a "warm
up" with a cap charging in time. Sounds like one of the rails is coming up
slowly

Eric

On Wed, Oct 7, 2020, 6:50 PM Simon Owen <Sowenbd@gmail.com> wrote:

Hi all
I am embarking on the likely arduous journey to resurrect my 7704A from
tick mode.

It was actually in tick mode when I bought it so I got a good deal (I
hope!). I got it home and pulled some plugins out and gave them a good
shove home and presto, it hummed to life.

I got a couple of months of tinkering with it but alas back in tick mode.

I have put together a test load and I'll be measuring voltages and ripple
shortly.

It just occurred to me that before its most recent death there was
potentially a warning sign: the scope would tick a few times before coming
to life. Then I remember it would tick for longer and longer, but I found
that if I pushed the beam finder button it would 'snap out of it' and get
down to business. This clearly didn't last.

Does anyone have any wisdom on this symptom so perhaps I will have an idea
of the likely problem? When it was running during its 'pre-death' period I
didn't notice anything else peculiar.

Assuming I can rule out the power supply as the cause of the trouble, I
wouldn't know where to begin!

Thanks a million
Simon Owen





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