|
Went to bed last night feeling defeated. Woke up determined to fight. Since my Tek 465M is failing, I decided to take a chance and hook up my cheap digital scope to the set. I started with taking waveforms 6 through 9, which are appended below, except for W6. W6 calls for grounding pin 7 to ground (chassis, correct?). When I did that the CRT displays a bright horizontal line so it was killing the vertical and the scope was flat lined.
As you can see, W7 and W8 look pretty good. Although if I am reading the schematic they should be at 30hZ and they are at about 60hZ. W9 looks terrible. Could K1 be responsible? That is the one couplate I did not replace.
V9 tube voltages seem close enough:
2 = -19
3 = -19
6 = 115
7 = -7
8 = 11.8
All voltages taken with a modern 10m input meter. The wave forms were taken with the set giving the best picture I can get. The schematic does say they should be taken with 50V PtoP at the CRT. I did not verify that but am going to sneak into the CRT area. Of course I had put the dang shroud back on so it isn't easy. I take it that should be between the chassis and pin 7 of the CRT?
Thanks!
|