Pilot tv 37

[mikeh]

Hi
Had a chance to work on this little guy and have it working again but I noticed that there is no adjustment for vertical linearity. This is the later model that follows the Sams. Do you guys have any suggestions on how to proceed with mods to improve the linearity issues?
Many thanks
Mike

[Sandy G]

That looks pretty dern good.... I dunno if I'd wanna Mess w/it too much...

[dtvmcdonald]

Actually that pic is simply horrible. And easy to fix.

There are two different schematics for the connections between the
vertical osc and amplifier: Sam's and Riders. Sam's has a 5.6 meg resistor
where Riders has two .0015uf caps and a resistor to ground.

Install the Sams circuit (check that resistor out of circuit) and add at least
another .01 uF in parallel
with each of the 3kV or higher .005 uf caps that
connect the vertical to the deflection plates. A total of .02uF is better.
Allied elec has good mylar caps for this, but if you use .02uf total
each, ceramic will work just fine (use 4, 6, or 10 kV ones), as
ceramics have nonlinearity problems only if they have lots
of AC across them, and at 0.02 there really isn't any.

See my thread about this in summer 2013.

[mikeh]

Thanks for the information I will try the mod this weekend. I missed your post in 2013 I will look it up.
Mike

[mikeh]

Business kept me away for awhile, finally had a chance to work on the TV yesterday. I changed the 4.7 meg resistor in the vertical circuit it was a 5.2 meg. Changed the high volt caps from .005 to .02 made a big difference in the vertical linearity. Want to say than you to dtvmcdonald for your advise and write up of the problem. The tv still has a few issues but the vertical much better. Now need to perform an alignment as the sound is out of sync.
Thanks