CTC-17 Vertical lock issue

[freakaftr8]

Hey guys,
one of my CTC-17's sprung a vertical lock issue on me tonight. I got around to replacing the horiz phase detector diodes with a couple radio shack diodes. Works great now but I noticed I have lost my vertical lock, it's been a bit touchy from the get go but it's completely out now, I can roll the picture both directions so it's not a pot failure and I can stop it from rolling but it wants to move the other way then. Whats up with it?
Thanks!

[DaveWM]

did you replace the sync sep tube?
check the voltage at the plate of the sync sep.
check the RC between the output of the sync sep to the vert osc?
check the cap coupling from the sync sep to the horz diode afc.

[Zenith26kc20]

Check the high voltage. Too (!) much HV will make you over adjust the height and vertical lin controls causing soft vertical.

[freakaftr8]

I replaced the 6KA8 sync sep last night thinking this was the fault. No change, im going to check some voltages on the tube tonight and at the Vert osc.

[freakaftr8]

Oh and the HV, last time I checked it wa dead on 25kv. My meter needle went wonky and I need a new probe now.. I will recheck the HV. Thanks guys, ill let you know what I find tonight

[DaveWM]

I was thinking that the cap (if a little leaky) that couple the horz sync to the horz sync diodes may be suspect, just cause its in the path of the part that was replaced and then the trouble got worse. That is if the RC to the vert osc is ok.

[freakaftr8]

Actually these were two different issues I was having. Wanted to tackle the horiz issue first. I'm thinking I'm going to check grounds on the horiz/vert/ afc board as the chroma boards grounds were wasted.

[freakaftr8]

Well here's what I got..

I noticed the horiz lock is still finicky, but at startup, almost like a weak tube, but it straightens out. With the vertical, still no lock.

On the 6KA8 sams points that between pin 1 and pin 8 of the 6GF7 there is a 220k resistor and a .033 10% cap. On pin 1 of the 6KA8 I have 52v and should have 120v. On pin 8 of the 6GF7 I have 300v where I should have 240v. If I put the meter lead on pin 8 to check voltages, vertical locks! Think the meter drops the voltage.

Something else is odd, on the 6KA8 pin 9, I should have 20v and im getting 52v, all other voltages on the circuits are within reason.

[ChrisW6ATV]

That sounds like it could be an intermittent contact issue. Disconnect the other probe and touch the + one to pin 8 again to see what happens. Or, you may have a bad ground connection on/to that board or part of it.

[freakaftr8]

Yeah ill check my grounds.. Thanks Chris! I never thought about it but it does kinda seem like a ground issue..