View Full Version : Motorola VT-71/TS-4J


7"estatdef
06-11-2006, 05:22 PM
Have been working on this one for a few days now. Have a raster with picture but it also has bars across it. What do you think the cause is? I've replaced most of the caps and a lot of resistors.
Terry

Don Lindsly
06-11-2006, 06:16 PM
Did you put the high voltage cage back on?

Don

7"estatdef
06-11-2006, 06:29 PM
Yup it's on but I don't have the aluminum shield on the crt. I'll give that a try. You think it's rf interferance?
Terry

Eric H
06-11-2006, 06:41 PM
Yup it's on but I don't have the aluminum shield on the crt. I'll give that a try. You think it's rf interferance?
Terry

Sure looks like it, the electrostatic sets are pretty sensitive to that type of interference.

7"estatdef
06-11-2006, 07:10 PM
Put the crt shield on but didn't make any difference. Did notice that the HV cage isn't at chaiss ground or B-. It's at RF ground though a 470k and .1 cap +100ohm resistor. All ok. Guess it's time to go play cards with my 9yr while I mull it over.
Terry

7"estatdef
12-27-2007, 07:43 PM
I think the problem was that the HV p/s cover was touching thee ground strap around the 7JP4. On these set that cover have it's own ground and it's not the same the crt and speaker. There is a piece of insulating paper under the HV cage were it mounts to the chaiss.
Those bars where making me crazy, I think this has got it.
tnx for help!
Terry