View Single Post
  #199  
Old 04-11-2015, 09:35 PM
Electronic M's Avatar
Electronic M Electronic M is offline
M is for Memory
 
Join Date: Jan 2011
Location: Pewaukee/Delafield Wi
Posts: 15,440
Quote:
Originally Posted by Phil Nelson View Post
It is a plain old direct scope probe. I tried adding a 2 pf cap in series with the probe and didn't notice a significant change.

I tried substituting a 100 pf and a 82 pf cap for the 270 pf cap in the tank circuit on the workbench. 100 pf raised the peaking point somewhat, and 82 pf raised it up to roughly 3.5 mc. I substituted an 82 pf cap in the TV, and observed no change or improvement.

I don't see any whiskers or solder crumbs anywhere on the socket, which I have cleaned and re-cleaned. I have tested the socket with an adapter in place, and tried running the TV with the tube in an adapter, with and without the shield.

When I tested the old coil (L42) in a tank circuit on the workbench, it responded the same as a new one. Substituting a new coil for the old one in the TV gives me the same result.

I guess I can't rule out a socket defect such as a hidden carbon track caused by a past shorting incident. That is a hard thing to disprove without stripping everything off the socket, at which point you may as well simply replace it.

Phil Nelson
You could always ohm out the grid pin with respect to ground and surrounding pins to look for abnormalities....
__________________
Tom C.

Zenith: The quality stays in EVEN after the name falls off!
What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4
Reply With Quote