View Single Post
  #36  
Old 04-18-2009, 08:08 PM
jeyurkon's Avatar
jeyurkon jeyurkon is offline
VideoKarma Member
 
Join Date: Oct 2008
Location: Central Michigan
Posts: 1,699
Found the problem

Well, using the 1N4007s brought the -HV up. I was a little too conservative with the resistors. I'm about 5 volts low, but that shouldn't be a problem.

I saw no change in the performance. The AM radio is working to a degree now without the loop, but that's not related to the -HV since it doesn't use it. It's just that there's a strong AM station in the daytime.

I'm amazed that the set had a picture at all. While trying to figure out why the video was so weak and the AGC wasn't kicking in I discovered that the primary on the first video IF transformer is open. I only had a picture because of the signal bleeding through.

It's probably hopeless to ask, but does anyone have a Sylvania 125-0001 IF transformer? I don't think Merit made a replacement.

I may have to rewind it which would be difficult. It appears to be coated with glyptal which is extremely difficult to remove. On the other hand, the coil shows no signs of having been over heated. It might just be a cold solder joint to one of the terminations.

I suspect that once I get a decent signal through the video IF stages my horizontal problem will take care of itself.

Oh, the CRT HV is 500 volts low. I can only get it up to 9KV. I should be able to get 11KV max and set it to 9.5KV. I think it's because I have a weak 6Y6-G in there. The one in the audio section is better, but it doesn't fit under the coffee can. Which is funny, because it's the Sylvania tube. The weak 6Y6-G that fits is a Philco. I have a 6Y6-GT I can try. I didn't because Wallace's recommends using a coated 6Y6.

John

Last edited by jeyurkon; 04-18-2009 at 08:12 PM. Reason: Forgot 6Y6-G comments
Reply With Quote