The scope is a Tek 422, and the power supply seems to be having
troubles. In any operating mode, except battery charge, the supply
whines. Not my main concern, but maybe related and needs to be fixed.
When in battery charge mode, the output voltage when loaded with a 50
Ohm resistor is 22.1VDC with 120VAC input, which is within tol of the
service manual, but when loaded with a 680 Ohm resistor, the output
jumps up to 57.1VDC. Unloaded voltage is 62VDC. All other supply
voltages are within tol. Any common problems with this supply? I
found a post about the whine a while back for another 422, but nothing
about the charging voltage drifting high. I haven't tried replacing
the electrolytics yet, which I will when I get time, it appears this
scope was built in 1965 and I'm sure they're all on their last legs.

Any help appreciated as always,
Steve Kamego

steve wrote in message ...
The scope is a Tek 422, and the power supply seems to be having
troubles. In any operating mode, except battery charge, the supply
whines. Not my main concern, but maybe related and needs to be fixed.
When in battery charge mode, the output voltage when loaded with a 50
Ohm resistor is 22.1VDC with 120VAC input, which is within tol of the
service manual, but when loaded with a 680 Ohm resistor, the output
jumps up to 57.1VDC. Unloaded voltage is 62VDC. All other supply
voltages are within tol. Any common problems with this supply? I
found a post about the whine a while back for another 422, but nothing
about the charging voltage drifting high. I haven't tried replacing
the electrolytics yet, which I will when I get time, it appears this
scope was built in 1965 and I'm sure they're all on their last legs.

Any help appreciated as always,
Steve Kamego


have a manual available if interested.

cl