[Test-Equipment] Scope info needed

[Gary Schafer]

Thanks for the reply guys! The scope is actually the military version 
the OS245. Pretty much the same as the 7603 except it is supposedly only 
a 60 mhz mainframe.
I do have a set of manuals for it.
I had a problem a few years ago where the sweep would not work. It 
looked like it was an unblanking problem. At that time I found a 
transistor loose in its socket on the regulator board. Fixed the problem.

This time it quite and looked like exactly the same symptoms. In fooling 
with the regulator board I somehow zapped the 5 volt regulator. I found 
the u973 (5 transistor array) bad. Looks like an rca CA3045F. Don't know 
how much luck I will have finding one of those.

When I fix that I still have the problem with the sweep.
Could be easy to fix or a real bear.
As old as it is I thought I might try and find something else. Actually 
these should be pretty cheap by now I would think!

By the way this does have the linear power supply in it.

All help appreciated.

Thanks
Gary  K4FMX

jbarnes wrote:
> All the 7603s that I have worked on have linear power supplies.
> 
> It is the larger members of the 7000 series scopes that have the switchers.
> 
> Check the power supply rails for short circuits.
> 
> Try operating the unit with 1 or 2 plugins. The power supply short could be in a plugin.
> 
> I have also seen ceramic capacitors go short taking down the rails.
> 
> Do you have access to a manual ??
> 
> Sincere regards,
> 
> John Barnes
> 73 de VE3XRY
> 
> ---------- Original Message ----------------------------------
> From: "J. Forster" <jfor at quik.com>
> Reply-To: jfor at quik.com
> Date:  Fri, 18 Mar 2005 17:14:10 -0500
> 
> 
>>Agreed on both points. The little dipped tantalums are a problem.
>>
>>If the power supply is damaged, it can be hard to fix. It's pretty complicated
>>in the inverter section. There are several internal fuses as I remember that are
>>worth checking first.
>>
>>BTW, this is an off-the-line switcher. USE AN ISOLATION TRANSFORMER.
>>-John
>>
> 
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