Re: 7904A and X-Y Display -- Help !

Albert <aodiversen@...>

Hi Jerry and Dennis,

I now verified this with a 7B53A in the A horizontal slot and in Ampl position of the Time/div knob. The switch S4488 should be slided inwards for normal XY-operation. In the slided outwards position the Z-axis is controlled by the time base amplifier in the B slot (Meaning that the trace is visible while the B sweep is running and blanked during retrace.) The B Intensity bulb gets lit then.
Like in the 7104, the switch is located at the right side of the 'scope, at the upper corner of the A13 board. Best viewed from rear side of the 'scope and switchable with your finger.


FINALLY, I did check the A and the B lights and in every combination of
switch settings I could think of the A light never went out or switched to
the B light. This is why I think you should try what Albert suggested. It
sounds like he has a 7904A in which case he would know what this switch


Try with S4488 (corner logic board A13) in the other position?

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