GE Locomative Smear

[Doug66]

Can someone tell me what is causing the smear on the left of the screen on my GE locomotive? I restored this set about 3 yrs ago, but this problem started about a year ago. I just pulled the cabinet off and replaced the 19BQ6 Horiz output tube, but that didn't help.

The Riders says the Horiz drive SB set an min counterclockwise, which I have done. Tweeking both horiz holds, horiz lin and horiz size doesn't seem to help.

[David Roper]

The first third or so of the scan is recovered energy, right? Try another damper.

[Jon F]

I have a GE 800d which used to have a very similar issue. Turned out it was the 25W4 (damper) even though it tested good on a bench tester. A NOS tube fixed the issue.

http://www.videokarma.org/showthread.php?t=260530&page=3&highlight=800d

[Doug66]

Thanks Guys, I ment to order a damper when I ordered the 19BQ6, and ordered the wrong damper. I'll order a correct one ( don't have another on hand), and try that.

[kramden66]

if the damper isn't at fault check to see if the horz lin and width are not open

[Doug66]

I found a seller on ebay that had two 25W4 damper tubes, so I bought both to compare. Trying both cleared the smear up but gave 2 vertical white lines towards the center of the pic. I can get those to disappear if I max out the horiz drive, and I didn't think that was supposed to be maxed out.

[Username1]

In the attachment you can see the top scope image - drawing the transition
point is where the scan line comes close to the center of the tv screen....

This puts the problem in the damper circuit.... Possibly this is a problem
with a capacitor effecting the shape of the wave as it's close to it's discharge
point, - before the next on time for the horiz output tube....

I'm going to say it's a capacitor issue, not a tube issue.....

(your pictures)
In that first picture on the right side of the screen, it sure looks like the end of the
box is no where near box shaped.... quite a pronounced bow in it. And in each
of the pictures you posted it looks like the lower right and left sides of the picture
are very out of focus..... and the line defining the box in the top picture sure
looks to be pretty wavy.... Are there other issues with this set...? Is the B+
where it should be....? is it as clean as it should be...?

.

[miniman82]

Classic drive lines, careful balance of the horizontal drive and wave shaping circuits is usually the cure for this.

[Doug66]

Careful balancing of the controls is what the Riders manual stresses. I did find out that the horiz lin and size coils are working. I went from min to max on each and found where they start to react. I think I've got all of them balanced out now. I'm going to give it one more bench test before I put the cabinet back on. Thanks for the input and help.