Controlling X/Y through analog switch in NSIIIa?

rwfriddle posted on Wed, Oct 21 2015 4:41 PM

rated by 0 users

Hello-

I understand if this is prying too much, but it is regarding the long obsolete NSIIIa controller so I thought I'd ask. We would like to take control over the X/Y by feeding in our own signal just before the HV amplification on the X/Y board. There is an analog switch (DG419) situated just before a buffer that leads into the HV amplifiers. It seems that for normal operation the switch is TTL low, and thus uses the main circuitry before HV amplification (I tested it during scanning and force ramp).

We are wondering if we could tap our signal into input 2 of this DG419 chip and have a digital control to switch between the normal NSIIIa signal and our own signal for the X and Y.

Can someone share what this DG419 switch is for? When would it ever be used in TTL low? Is it ok for us to bypass it with our own signal? Thanks.

-Ray