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Hi,
I bought a 7834 which in general is working fine. One strange thing is, when the reduced scan button is activated, vertical works as expected, waveform and readout scale down. On the horizontal axis, the scaling of the waveform changed as expected, but the trace is still full length. Horizontal readout is functioning is re-positioned correctly. My question is, where in the schematics is the shortening of the traces supposed to happen?
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Best regards,

Fred S.

I haven't checked but I am assuming the 7834 reduced scan is the same as the 7934. It works by doubling the cathode voltage on the CRT so that the deflection sensitivity in X and Y are each reduced by a factor of two. In normal scan you would have had a substantial overscan that you can confirm with the horizontal position control on the timebase. I don't suppose your timebase is in X10 expansion is it?

Roger

--I haven't checked but I am assuming the 7834 reduced scan is the same as the 7934. It works by doubling the cathode voltage on the CRT so that the deflection sensitivity in X and are each reduced by a factor of two. In normal scan you would have had a substantial overscan that you can confirm with the horizontal position control on the timebase. I don't --suppose your timebase is in X10 expansion is it?

--Roger

Hi Roger,

thank you for your advice the relay K2014 was not switching, bad solder joint.

Best regards,

Fred S.