[Test-Equipment] Putting power to 7904 out of storage

[Dennis Wade]

Thank you all for the considered replies.  I appreciate the response.
I'll let you know how it goes.

          Dennis


On Mon, Feb 2, 2009 at 8:23 AM, Larry Will <lhwill at verizon.net> wrote:
> I concur with John,
>
> I have used the bulb option on Tek scopes and modern TV sets and I
> know other who do the same.
>
> The Tek 7904 supply if overloaded or in trouble will appear dead but
> if you listen carefully you should hear a tic tic tic sound
> indicating repeated attempted starts.  The Tek service manual has a
> good section on troubleshooting that supply and I have removed them
> from the scope to do unloaded tests.  They should come up and deliver
> the miriad of DC voltages that they do just sitting on the
> bench.  When it works that way its time to put back in scope and see
> if any other troubles are in the mainframe or plug-is.  I look for
> obvious dead shorts on all DC busses to try and isolate any failed
> components.  Just time consuming.
>
> Larry
> w3LW
>
> At 11:00 AM 2/2/2009, you wrote:
>>IMO, bringing up a switcher on a variac is iffy. I use a line cord fixture
>>with a few ordinary light bulbs (parallel connected) in series with the
>>hot side. This prevents fires in case of a serious failure. On a good
>>supply, they will have little impsact, except for inrush limiting.
>>
>>Best,
>>-John
>>
>>
>>
>> > Dennis,
>> > You may be right about the switching PS requiring different start-up
>> > procedure.  In any case, I'd recommend monitoring the input current to
>> > be sure it does not get excessive.  I have used, for decades, a
>> > metered variac to power up long dormant equipmwnt; maybe even saved a
>> > few power transformers.
>> >
>> > If you have a variable voltage DC supply, you might consider applying
>> > dc to input of DUT PS filter circuit and monitoring the current as DCv
>> > is increased.  This procedure will also reform long dormant
>> > electrolytics. Cheers, Chase/K4AFW
>>
>>
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-- 
Dennis L. Wade
KG6ZI
Carmichael, CA