View Full Version : Motorola ts18


timmy
02-27-2017, 12:25 PM
Ok I got another Motorola ts18 and recapped it and it works sound and picture however the verticle hold is all the way to one end and it still rolls but sometimes it does stop but it seems like both the vert and horiz are not right when the pic is still the horiz goes and has to be adjusted but it's the verticle. I subbed all the verticle trimmer caps, 100 250 1000 pf and no difference. I'm wondering since I temporary put in 2 .002 for the horiz and 1 .004 and 1 .0047 for the horiz .what I'm thinking is theses caps except the .0047 are ceramic disc and since I know they should not be used I thought I could get it up and running with these caps then order the right ones so is it possible that this is what is making the vert unstable and causing the vert pot to be at one end. are these caps noisy for this circuit. All the key resistors for the verticle have been checked.

Zenith26kc20
02-27-2017, 03:14 PM
I used ceramic disc caps years ago on my TS-4 and never had issues. I did have to replace them when one ceramic disc failed in the vertical. The problems I have had were caused by too much B+ when I replaced the seleniums with silicon diodes and did not (at the time) install dropping resistors.
Make sure all of the high value resistors are good and that your centering adjustments can go thru their range properly.
Also, excessive sweep height can make the vertical touchy. Since the TS-4 and the TS-18 are close, it sounds like too much B+. Also, If I remember right, the vertical output tube can be a problem. I remember trying a few before the set settled down.

timmy
02-27-2017, 04:40 PM
I used ceramic disc caps years ago on my TS-4 and never had issues. I did have to replace them when one ceramic disc failed in the vertical. The problems I have had were caused by too much B+ when I replaced the seleniums with silicon diodes and did not (at the time) install dropping resistors.
Make sure all of the high value resistors are good and that your centering adjustments can go thru their range properly.
Also, excessive sweep height can make the vertical touchy. Since the TS-4 and the TS-18 are close, it sounds like too much B+. Also, If I remember right, the vertical output tube can be a problem. I remember trying a few before the set settled down.
I do find that the vert is stable when I adjust the vert size to smaller but the vert pot is still maxed. I changed the seleniums to diodes and I think the b++ is 257v and b+ is 140 v I did check the hi value resistors but none were bad enough to change. I did try another 6sl7 but no change. With the ceramics the pic is perfect, however I do notice when I shorten the pic by the vert size it's clear but filling the screen it goes out of focus just slight. 2 other ts18 s I didn't have this problem.