Re: Fixing a 7603 Power Supply


Eric
 

Jeff,
Excellent news Jeff. If you have trouble locating the POT let me know. Ill see what I can do to help there.

Eric

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Jeff Dutky
Sent: Sunday, July 11, 2021 9:32 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Fixing a 7603 Power Supply

SUCCESS!

The 7603 "works" after a fashion. The reason that I don't see anything on screen is that the INTENSITY pot is very, very dirty and not making contact through most of its range of motion. If I rotate the knob rapidly back and forth I am able to get the CRT to show a trace in fits and flashes, enough that I can see that I'm getting signal and that the sweep is working.

When I went to unmount the pot from the panel, after I removed the knobs, I found that there was some kind of grease leaking around the outer shaft. The inner shaft also appears to have been straightened. This is a standard Bournes modular pot with three elements. My understanding is that these should be well sealed, and I do not expect to find grease leaking around the shafts, so I'm guessing a previous owner tried to recondition the pot. I might simply have to order a replacement.

-- Jeff Dutky

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