[Texasrocker]

Thanks for your help Pete & Richard! These type sets arent my faves to service!!! Im hoping the silver-micas in the tuning-slug type IFs are OK? I did get the set working again without the "intermittent" prob so far. I noticed while I was carefully probing around the under-chassis point-to-point connections, I got full-vol by pushing fairly hard on one of the orig solder connections at the 2nd IF primary connections. Low & behold, I added abit of new solder to orig Zenith( cold solder joint) and the set came on full vol as it should. Ive bench tested it now for approx 4 hrs without any dropouts in performance. The set now receives stations all across the dial. Since this is a customers radio, I will let it play on the workbench several more hrs to see if the micas are also bad in the IF cans before I rtn it to customer.
Another prob I found on my workbench, is my vintage AC isolation trans is "upping" my actual AC line voltage! I didnt realize that until I checked. My actual incoming AC line voltage is running around 124 volts, & my AC Isolation trans outlet was reading around 134 volts AC! If I had realized that, I would have cranked the Iso Trans AC back down with my variac!Wonder whats up with that happening with my Iso Trans also?
I copied your posts to keep in my files for future reference on these type chassis repairs!! Thanks again!! If the set fails again, I know what to check next via your suggestions! Randal