Motorola ts907 low hv - Page 44 - Videokarma.org TV - Video

timmy · #**646** 10-16-2022, 12:53 PM

What I find odd is the voltages on v1 v2 210 on pin7 and pin 8 100 but I’m getting 198 pin 7 and 60 on pin 8 but if I pull v1 the voltages on pin 7 come up to 130

timmy · #**647** 10-16-2022, 04:09 PM

I could use any idea what would cause vertical centering to not work at all but all other vertical works hold, linearity, height, but no centering screen don’t move at all. The centering pot measures 1.5meg but sams shows it to be a 2meg.

Yamamaya42 · #**648** 10-16-2022, 04:51 PM

Quote:

Originally Posted by timmy

I could use any idea what would cause vertical centering to not work at all but all other vertical works hold, linearity, height, but no centering screen don’t move at all. The centering pot measures 1.5meg but sams shows it to be a 2meg.

You have nothing to center on the screen, no video.
if there was something to see, then you would see the effect of the adjustment.

if you were to feed video in like before, then you would see it working most likely.

timmy · #**649** 10-16-2022, 04:59 PM

I thought the whole screen goes up and down not the image alone.

timmy · #**650** 10-16-2022, 05:14 PM

Pin 1 of 6cg7 is supposed to have 80v on it but it has a ridiculous 180v there this tv is full of surprises.

Electronic M · #**651** 10-16-2022, 05:23 PM

Quote:

Originally Posted by timmy

I thought the whole screen goes up and down not the image alone.

Unless you have vertical underscan you won't see it move without video, and even if you do it's possible the osc will have enough jitter free running that you won't notice.

That said sets with electrical centering control typically run a DC current through the yoke to control centering. The pot it's self could be bad or the circuitry feeding it. Before declaring it bad though, I would definitely confirm operation with video fed in.

jr_tech · #**652** 10-16-2022, 05:32 PM

Quote:

Originally Posted by timmy

I could use any idea what would cause vertical centering to not work at all but all other vertical works hold, linearity, height, but no centering screen don’t move at all. The centering pot measures 1.5meg but sams shows it to be a 2meg.

The vertical centering pot (R-16) is 10 ohm! It is shown on an output winding of the vertical output transformer (T-2).

jr

timmy · #**653** 10-16-2022, 05:40 PM

Quote:

Originally Posted by jr_tech

The vertical centering pot (R-16) is 10 ohm! It is shown on an output winding of the vertical output transformer (T-2).

jr

Yes your right I knew that lol my mistake

timmy · #**654** 10-16-2022, 05:52 PM

I wish I knew if someone fooled with the overall alignment of this set but if it has been messed with it can’t be to far out since I can make out some things on screen but of course it’s distorted.

timmy · #**655** 10-16-2022, 07:36 PM

Has anyone ever had a video detect germanium diode test good but be bad in circuit.

Yamamaya42 · #**656** 10-17-2022, 07:50 AM

What you would see if your IF section was VERY messed up...
Absolute and total randomized garbage on the screen as you try to tune in something, wildly changing color (unless color killer is turned down), herringbone patterns that will react to fine tuning, but no real video info getting through at all.

You could try to replace the video det, but it most likely won't help as the problem is most likely before it.

So it seems you have 2 choices.

1)
Find someone nearby with the equipment and knowledge to help you debug and align the tuner/ IF sections.

2)
Rig it for direct A/V input, and bypass the front end for now using a easy to build video amp to match the level needed for the set.

timmy · #**657** 10-17-2022, 09:56 AM

Well I put a new video detect diode in certainly was not an easy thing to do so I’m going to try it and as for alignment there is only one coil that shows the slug was moved it’s the same coil where the diode is A4 so if that was messed with then if I’m careful I could turn the slug in or out counting the turns in or out and see what occurs I have nothing to lose at this point.

timmy · #**658** 10-17-2022, 10:29 AM

No difference but the video injecting still works and I did notice the ac waving in the screen for the first few minutes caps are good unless ac is getting in somewhere. The block lines are not in the picture the camera is causing the lines.

timmy · #**659** 10-17-2022, 10:32 AM

How can I stop the blue arc that is between the rectifier and the 2 wires for the 3 volt heater

timmy · #**660** 10-17-2022, 10:54 AM

Well at this point it doesn’t matter how much current this set is drawing because the 3 voltages are low again and I still think there is some stray voltage getting in somewhere affecting the video and the voltages. being the output diode gets really hot which I’m sure is not supposed to get this hot.