Hello, all....I have been on the ARF's for a few years now and have enjoyed lots of useful radio feedback and info from the great guys over there ....however I've started my 1st TV resto, so I thought it might be most helpful to post here for this set's remaining issues.
After a complete re-cap, and contacts and controls cleaning I have a pretty decent picture with the exception of a general lack of contrast, some stubborn retrace lines, and an ion trap that I can't adjust for optimum brightness.
https://www.dropbox.com/sh/vsodavszt...030988.JPG?m=1
I combed thru all the video circuits looking for out of tolerance resistors and found a half a dozen or so and replaced them, but no change, so I am shelving the contrast issue for now as I'd like to check the associated tubes before proceeding.
(I am currently out of the country, and don't have my tube tester and other test equip with me....DMM only). As a matter of interest I went thru the Sams voltage checks and found only 20VDC on the cathode of the 12LP4....Sams shows 130VDC??? The Philco factory schematic shows no voltage measurement here.
Same drill for the retrace lines...I checked the DC resto area, and found nothing amiss, so further ideas here would be welcomed.
The ion trap magnet adjustment is a bit of a puzzle....the brightest screen occurs when the trap is pulled back aginst the CRT base, but at a cockeyed angle that won't stay put....the spring tension pulls the trap back straighter as soon as I let go of it!
https://www.dropbox.com/s/7ryx2cqn29ntwuw/P1030987.JPG
As you can see, it is still tilted a bit, but the picture actually gets brighter if I twist it a bit more....it just won't stay that way. Does this seem like a defect in the internal
crt element arrangement? I thought of removing the spring and super gluing the trap back on, but that's not a very confidence inspiring fix! Ideas here as well???
Thanks!
Mark