question about a 8-t-241

[stusnyder]

Originally Posted by Penthode

I would be glad to help. I have owned and used an 8T243 for 42 years and have fixed a number or these chassis since. It is my favorite design.

Are you familar with the 6-t-71? I got a odd problem with one.

[Penthode]

Originally Posted by stusnyder

Are you familar with the 6-t-71? I got a odd problem with one.

I have worked on a few.
What is the problem?

[stusnyder]

Originally Posted by Penthode

I have worked on a few.
What is the problem?

On the bench hooked up to a 5" test crt I get a decent picture. Back in the cabinet hooked up to the 16" crt I get no vertical lock.....

[Penthode]

Originally Posted by stusnyder

On the bench hooked up to a 5" test crt I get a decent picture. Back in the cabinet hooked up to the 16" crt I get no vertical lock.....

Note that on the design of the kcs47 chassis that the sync take off point is after the contrast control at the video amplifier. If the contrast is reduced (less video amplifier gain) the sync amplitude is reduced. This may aggravate an already weak (problem) sync condition. Note that the kcs66 reverted back to constant amplitude sync (sync take off before the contrast control).

I assume that you have replaced the capacitors in the sync separator section? Do you have a scope to check sync amplitude? Do you notice with the test CRT if the contrast control setting is higher? Does adjusting the control to increase the contrast help with vertical sync?

Otherwise it is checking voltages, waveforms and substituting tubes in the sync section?