Weird picture issue GE 805

[Chris K]

I'll start by saying the threads I have posted regarding horizontal issues on multiple TVs have all been resolved. My Admiral, Crosley and Hallicrafters projects are done. Even the Crosley misalignment of sound and picture with the continuous tuner got dialed in with everyone's help here. Before I dive back into the deep Dumont RA-103 rabbit hole, I want to get the GE 805 and its problems off my bench!

I have, what I think is a weird vertical deflection issue. The left side of the picture is about 10%-15% less high than the right hand side of the picture. I'm pretty certain the problem is with the bottom of the image. When I run broadcast, test patterns etc, the top of the picture is straight across the screen with no distortion. The bottom, left corner of the picture isn't deflected down enough and there is a straight, angled image lower border of the picture down to the right side picture corner. It's there with the 10BP4 and the 5" technician CRT that doesn't use the ion trap or focus coil. The yoke resistors all ohm out fine and the yoke's 47pF mica cap is spot on and isn't leaky. Sometimes, when I tap controls, tubes, the yoke etc. A La Shango, it snaps in to full, symmetrical vertical deflection but it doesn't stay that way long, maybe a second or two. Has anyone encountered an issue like this?

[old_tv_nut]

Can you narrow down what is sensitive to tapping? The yoke maybe?

Maybe check for intermittent short between vertical and horizontal windings?

[Chris K]

I hit the yoke housing and it snapped in and out. Sometimes when I cycle and shake the contrast knob it does it. I tapped the vertical 12SN7 tube and it snapped in and out. The event doesn’t seem localized. It almost seems like something is intermittently conducting. Maybe a bad solder joint somewhere?

[Username1]

.


You need to localize the movement of parts - Don't tap stuff, start moving stuff
with a insulated plastic rod, pencil whatever. Just touch, or move the yoke
wires, move the tubes in the socket, touch the knobs, turn it on it's
side, & touch components - put a little pressure on the parts
under the chassis.


.

[Chris K]

The problem was in the yoke. It was intermittent going through in and out of even alignment when I tapped on the outside of the housing. I scavenged a yoke out of an 805 parts chassis and it works well now.

[old_tv_nut]

Originally Posted by Chris K

The problem was in the yoke. It was intermittent going through in and out of even alignment when I tapped on the outside of the housing. I scavenged a yoke out of an 805 parts chassis and it works well now.

What you described sounded like some horizontal deflection voltage affecting the vertical or vice versa - easiest way for that to happen I could think of is a short between the H and V windings.

[old_coot88]

Apparently it was intermittent leakage tween the H and V windings rather than a hard short. Every case I ever seen gave a fully trapezoidal raster and was not intermittent.

[Chris K]

Maybe it was my imagination. The time interval I thought the picture was correct was so brief maybe it was wishful thinking! Anyway, below is the current state. Gonna concentrate on the cabinet next. Always wanted one of these "locomotive" style TVs!

[Chris K]

I cleaned the cabinet as best I could last night. The cigarette tar that came off of it was insane! I thoroughly went through it inside and out. When I did it a second time, there was still brown residue coming off it. I remember those days of smoke filled rooms and offices. It wasn't unusual to view an evening news broadcast with the anchor having a burning cigarette in an ashtray on the anchor podium. My neighbor, a chain smoker, used to walk around her house with a cigarette in one hand and an ashtray in the other all day long. The TV didn't smell when I got it but I could smell the tar as I was cleaning it. Amazing and a bit disgusting.

[Yamamaya42]

If you think what it did to the surfaces and insides of TVs and radios was bad, just imagine what it did to the insides of THEM!

[Chris K]

Originally Posted by Yamamaya42

If you think what it did to the surfaces and insides of TVs and radios was bad, just imagine what it did to the insides of THEM!

Lungs just as brown and tar filled. My Greek father-in-law was a chain smoker and a vigorous, dancing, energy filled lover of life who woke up one morning with a bloody cough at 72 and was gone in a year. I had many aunts and uncles who smoked unfiltered killers like Lucky Strike, Chesterfield and Camels who had similar fates at young ages. One uncle died at 56 from cancer of the throat. Four out of my Dad's 5 siblings smoked themselves into early graves none living past 75. Dad was a light smoker who quit in his late 40s and he's still going strong. He was 94 years old on February 10th. An easy to interpret family experiment with very clear data and outcomes!

[jr_tech]

Originally Posted by Chris K

I cleaned the cabinet as best I could last night. The cigarette tar that came off of it was insane! I thoroughly went through it inside and out. When I did it a second time, there was still brown residue coming off it. I remember those days of smoke filled rooms and offices. It wasn't unusual to view an evening news broadcast with the anchor having a burning cigarette in an ashtray on the anchor podium. My neighbor, a chain smoker, used to walk around her house with a cigarette in one hand and an ashtray in the other all day long. The TV didn't smell when I got it but I could smell the tar as I was cleaning it. Amazing and a bit disgusting.

Perhaps you could also be scrubbing off a surface layer of degraded (oxidized?) bakelite?

http://www.retrofixes.com/2013/08/re...-bakelite.html

jr

[Chris K]

Would that be sticky?

[jr_tech]

I would describe the surface as being dull and slightly rough rather than sticky.
YMMV
jr

[Yamamaya42]

If you have ever seen “Mister Radio” on U-tube, he has always used something rather unexpected on bakelite after cleaning, with remarkable results! Simple car wax, takes a lot of work and buffing, but it brings it back to the new type shine.