Antique T935A

I was given an antique T935A.  At first I thought channel 2 was dead but the more I fiddled with it, the better it got.  Seemed to be a problem with the push-button switches.  So, after months of playing around with it I finally took it apart, cleaned out the dead spiders, and used some DeoxIT Gold G5 on it.  After putting it back together the buttons and knobs now all work great.  BUT (there's always a but), I've lost almost half of my screen brightness.  With the intensity knob at max, it's about as bright as it used to be at around 50 to 60% on the intensity knob. 

I've read the manual and I don't see any other internal intensity adjustments.  I've taken it apart again and still don't see anything besides R412. 

Could I have bumped some other adjustment that would affect intensity?

Thanks!

-Farren

Hi Farren,

It's normal for the resistance of a pot to go down after cleaning it.
If the intensity is too low then you should check the Z axis adjustment pot (there should be a procedure for adjusting it in the manual).

Thanks!

I've found the X and Y axis adjustments, but not the Z-axis.  It is usable and maybe over time as the DeoxIT wears off / dries up, I'll get some intensity back....

-Farren

Hi Farren,

I think that's unlikely, the DeoxIT probably cleaned off some gunk that was increasing the resistance of the pot, now it's back to normal (worth testing it to make sure though).

It's possible that's just the intensity that it was designed for.

You should check the bias of the Z axis amp and the HV section, those being off would explain what you're seeing too.