I am looking to replace a 20K pot/switch in my 453. It’s the variable on/off control for time/division, channel B, located on the side of the scope in a recessed panel. The panel swings out easily for servicing when the cabinet is removed. But I can’t figure out how the pot is mounted to the panel. Behind the knob there is...nothing. No typical retaining nut on the threaded shaft. How do I remove this pot? How is it mounted? Thanks.

Richard

Richard,
In the exploded mechanical drawing of the 453A manual there is a sub-panel behind the outer panel of the swing out section. The pot mounting nut is behind the outer panel. I assume the 453 is similar.
--John Gord

Hello, John,

Thank you. I uploaded just now two photos...the front panel and the rear panel. I can’t say that I see a pot mounting nut on my old 453 unit. Where should I look?

Richard

On Fri, Sep 25, 2020 at 02:08 AM, Richard P wrote:

I can’t say that I see a pot mounting nut on my old 453 unit. Where should I
look?

Remove the aluminum cover sideplate, mounted with two nuts accepting Allen screws (Astig and Trace Rotation) and the variable time/div knob.
Underneath, you'll find the nut holding the pot. It's mounted on a recessed part in the extrusion.

Raymond

I see it. Thank you. Very, very strange. Looks as though I will need to remove the 2 fuse holders, too, to remove the panel to access the nut holding the pot. Why in the world did Tek make that so complex and difficult? But I appreciate the assistance.

R