Mighty Monarch of The Air

[old_coot88]

Say hey! Try the fine tuning. When you get some recognizable video, try the horiz. hold as the horiz. frequency looks to be quite a ways off. What does the raster do now when you turn the contrast control stop-to-stop?
Mayhaps some kindly soul will post the left-hand side of the schematic. It's hard to tell if there might be some kind of AGC control there or not.
oc

[vts1134]

I think the horizontal is seriously off. I'm sniffing around the horizontal osc tube right now. I'm getting some off voltages (even more so than my high across the board on the rest of the set.
Pin 1 should range from -1.8 to -2.5. If I adjust the horizontal afc to get -1.8 on the high side of the horizontal hold then I get -12 on the low side.
Pin 2 should range from 170 to 130. It's ranging from 210 to 125 so that doesn't sound too far off there.
Pin 3 should range 4.3 to -.8. It's ranging from 21 to 5.4.
Pin 4 should be -55. I'm getting a strange reading on this one. My meter keeps jumping from -73 to out of range.
Pin 5 should be 165. I'm getting the same meter behavior on this pin. It's jumping from 186 to out of range.
Pin 8 is the heater. It's spot on 6.3.
What do you thinks happening on pins 4 and 5?
Are the voltage problems on pins 1 and 3 a symptom of my frequency being totally out of whack.
The contrast control does change the raster, buts it's hard to tell how much it changes without a proper picture.

I don't know how to post the schematic short of just taking a picture of it, but I can't get a readable picture. If no one else can post it here then I can try taking several pictures close up to make it readable.

[old_coot88]

Don't worry about posting the rest of the schematic just yet. Need to get the horiz. sorted out first. Can you adjust B1, the horiz. frequency adjustment? Caution: if it's a powdered iron slug with an internal hole requiring a hex tool (which is doubtful), don't try to adjust it without that tool. If it's a brass screw shaft with a screwdriver slot in the end, you're good to go.

If the adjustment doesn't turn easily, don't force it.

[old_coot88]

Originally Posted by vts1134

.
What do you thinks happening on pins 4 and 5?

Pins 4 and 5 are the grid and plate of the oscillator, respectively. They carry a high level, complex waveform which causes a digital meter to go nuts. The voltages are probably OK since the oscillator is obviously running very robustly.

[vts1134]

The horizontal afc is a easily adjustable. This is what I adjusted to get the high side of pin 1 to -1.8. I can adjust it from end to end without any problems (it's a screw tip btw). I cannot seem to lock in the picture no matter where it is though. I am adjusting it in conjunction with the horizontal hold control. I traced most of the capacitors that I replaced in that area and couldn't find one I missed, or misplaced. I'll try to get to the rest of them today. Is there another method to use with the horizontal afc besides turn it until you get a picture?