Here's some info I found on the web:
http://evilfurnaceman.tripod.com/tvs...del-8ts30.html
"THE TUNER DETENT ASSEMBLY IS EASILY BROKEN. REPLACEMENTS ARE IMPOSSIBLE TO FIND. WHEN CLEANING THE TUNER IN ONE OF THESE, DO NOT USE CONTACT CLEANER WITH ANY KIND OF LUBRICANT. IT WILL SEND THE SOUND CARRIER INTO OUTER SPACE. I USE COTTON SWABS DIPPED IN ALCOHOL, OR A NON-LUBRICATING CLEANER. ALSO, THIS SET HAS CHANNEL 1."
http://antiqueradios.com/forums/view...hp?f=3&t=10886
"Some old tuners have a springy strip anchored to the tuner shaft. This has a cutout for a ball bearing which clicks into little depressions in the front plate of the tuner. If the spring breaks, the ball falls out and you have no detent - the switch will just glide from channel to channel. If anyone has ever found a repair for this, I'd like to hear about it;"
"I have a fix for the tuner detent problem. I ran into the same problem on a 630TS which I recently restored, which of course uses the same tuner. Luckily, it is fairly easy to dis-assemble the shaft from this particular tuner; I don't have it in front of me at the moment but there are just a few screws accessible from the front around the shaft, which when removed allow the shaft and detent mechanism to be slid out the front. Be careful not to disturb the positions of switch sections when you slide it out!
As was mentioned, the problem is usually caused by a broken spring clip and a missing ball-bearing. I drilled out the rivet holding the old spring clip and fashioned a replacement from a piece of scrap plastic with 3 drilled holes: one for the shaft, one for the rivet (replaced with a small nut and bolt) and one for the ball bearing. I replaced the missing ball bearing with an ordinary brass BB. It works great, though probably not as "crisp" as the original since the plastic is more flexible than the spring steel. Luckily there's plenty of extra room in this tuner to make these mods.<P>I agree that this is an excellent chassis design and well worth the restoration effort - I also have a restored RCA 9PC41 projection TV which as mentioned uses the same circuitry. The picture is amazingly sharp and clear, despite being blown up from a 5" CRT to a 25" diagonal screen. This chassis also has all of the required adjacent-channel traps to get a good picture direcly off of cable."