Multiple Images on Display - Videokarma.org TV - Video

Nuke · #1 11-25-2011, 06:43 AM

Working on an Admiral 20x12 chassis. Set is recapped. However, the display shows 3 or 4 images lined up vertically next to each other. What's the cause of that?

Big Dave · #2 11-25-2011, 09:18 AM

Horizontal oscillator is running off frequency. Adjust the oscillator coil until the picture is right. Also, be sure no micas fave failed.

teevee · #3 11-25-2011, 11:05 AM

Multiple images would mean that the horizontal is running too slowly, Make sure the caps in that area were replaced with the correct values, (I verify these against what was taken out, there may have been production changes from what the schematic shows) And, check the associated resistors. A quick method of localizing the trouble would be to disable the horizontal AFC circuit, and see if a single picture can be had by adjusting the horizontal hold (It won't "lock" with the AFC disabled, but you should be able to adjust for a single image) If you can't, the problem is in the oscillator circuit. If you can, re-enable the AFC, and if that pulls it off freq, the problem lies there...

teevee · #4 11-25-2011, 11:17 AM

Ok, pulled the SAMS (100-1) and ammending my above, You disable the AFC by removing plate voltage from V14 pin 2. (Disconnect the wiper on the horiz hold control) adjust the HORIZ FREQ for a single image. This is a Synchroguide type circuit, and the adjustment procedure can be found on the web.. (Usually, they start with jumpering the sinewave coil, in this case jumper across R72)

Penthode · #5 11-26-2011, 08:17 PM

Line up vertically: does that mean the pictures are lined up in a vertical row one on top of another or are the multiple pictures lined up horizontally side-by-side?

Nuke · #6 11-26-2011, 08:38 PM

About 4 or 5 lined up side by side. Also I need to have the tuner slightly between the channel indents to pull the station in. Sounds like alignment issues?

bandersen · #7 11-29-2011, 06:42 PM

Quote:

Originally Posted by Nuke

About 4 or 5 lined up side by side. Also I need to have the tuner slightly between the channel indents to pull the station in. Sounds like alignment issues?

I've had several Admiral sets like yours exhibit the same tuner issue. Cleaning the contacts fixed it up.
There are detailed instructions in the Riders service info for adjusting the horizontal oscillator and horizontal lock controls also sample waveforms if you have a scope.

Username1 · #8 11-30-2011, 04:11 PM

hummm.... Picture in picture, in picture, in picture, in picture.....?!?!?! But all one channel right...... not that cool......

Nuke · #9 12-01-2011, 07:29 PM

I need to get underneath and check resistors I think. Definitely will find some time this weekend,

Nuke · #10 12-01-2011, 07:32 PM

Life is what gets in the way of my restoration projects.

Nuke · #11 12-03-2011, 06:13 PM

Ok - Finally figured it out by checking resistor values.

It was the 120k voltage divider resistor coming off the front horizontal control. It read .7 meg . Changed it out that fixed it. What I've been finding is when troubleshooting a major problem after recapping - look for resistors that are waaaay out of spec. Something up to to 20% off is not likely to cause a major problem such as this. Now it's just a matter of going back and changing those resistors that are somewhat out of spec and checking the alignment and of course, cleaning. Now if I can just get my scope going.

Yes, it is a Wonderful Life

bandersen · #12 12-03-2011, 09:17 PM

Congrats