Adventure in tracing down jitter


mongteen@...
 

Hello,

I have a RM31a that has a 54x CRT that works reasonably well. Thanks
Dean :) There is a slight horz. jitter about 2mm worth. So I check
the left deflection pin and see that there was no jitter. I check the
right deflection pin and see jitter. So I go about measuring and
changing tubes associated with the right deflection pin. Then I
sleep on it for a while. It occured to me to check for jitter at very
low sweep speeds. I connect my 7704a to the right deflection pin set
the coupling to AC and volia I found that the jitter is 120 Hertz. So
I measured the 500 V supply and found ripple of about 1 volt PP. So I
added a small cap to help filter out the ripple and the jitter is
gone!

The moral of the story is that alway check the PS first! I fell in to
the trap of seeing that everything else worked OK and assumed the PS
was OK.


Windsor

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