Real progress on my RCA 630TS!

[Jonathan]

Through all of your help, I made some real progress on this 630TS chassis. When I replaced all electrolytics, I put one in backwards, and it took me almost 5 years to figure this out! I put in backwards C221C, which is 10uF, which caused R179 to burn up because of the excess current flow. This original resistor went all the way down to 200 ohms, and caused C225A to always fail on me. At first I noticed the burnt resistor, so I changed it and the C221C replacement released it's smoke as well as the replacement resistor discolored because of how hot it got.

After taking a break and thinking I should trace back from the +275V that connected to the resistor, I noticed C221C was in wrong! It being backwards caused this chain to fail. And I completely recapped it about 5 years ago, and just about gave up because I could not get the power supply section to work.

Well, now things seem to work. The B+ is a little high, about 30 or 40V higher than it should be on the schematic, but the tuner, audio IF, discriminator, amp, and speaker seem to work so far. I resoldered the 300 ohm RF cable to the screw terminals and connected my cable system of 3 analog channels. I have TV signals on channels 5, 7, and 8, but I can only get channels 7 and 8 to come in. I do get good, clear audio from both channels 7 and 8, so that is a start! Power, tuner, and audio sections work! I'm listening to the audio of the Weather Channel right now as I type this. Soon I will put in the HV tubes and test with the picture tube to see what picture I get.

Audio gets loud and clear then quiet and distorted, and I think it's because the dirty tube sockets and tuner. How do I clean this tuner? How can I clean the corrosion from the tube sockets? I'm not sure how to clean either of these. Might be a fine tuning problem, but I'd guess it sounds like a dirty contact.

Thanks.

Jonathan

[Phil Nelson]

It's not uncommon for B+ to be a little high, since our line voltages are higher than the 117vac specified in manuals of that day. I wouldn't worry about it for the time being. Longer term, if it bothers you, you can run the set from a variac or humbucking transformer to reduce the line voltage.

Cleaning the tuner and tube sockets is a good idea. Before that, I'd clean the volume control and other potentiometers. Dirty pots are almost universal in TVs of that vintage, and sometimes a simple cleaning can work wonders.

If the control case has a little opening by the terminals, you can spritz DeOxit into the opening, then work the control all the way back and forth a number of times. Let the cleaner dry before powering the set again. Some controls don't have an opening; you can open those by carefully prying up little metal tabs on the case. Don't bend the tabs too hard or they may break off. This is easier to do with the control removed or at least loosened from its mounting nut and moved back from the chassis.

I clean tube pins by gently brightening them up with very fine sandpaper. After the pins are clean, you can clean the socket (at least somewhat) by spritzing a little DeOxit into the socket holes and/or on the pins, then plugging and unplugging the tube a number of times. Take out the tube and allow enough time for all the cleaner to evaporate. If you do one tube at a time, you won't risk mixing them up.

The contacts on tuners can become oxidized, like any switch contact or control surface. Do not use sandpaper or anything abrasive to clean tuner contacts. The lazy man's cleaning method is to spritz DeOxit on the contacts and work the tuner through all of its positions several times. A better method is to dip a Q-tip in a little DeOxit and rub each contact surface. After cleaning, you can go back over every contact with an electronic lubricant (also made by CAIG).

If you're getting reception on a couple of channels, I'd go ahead and install the picture tube to see what you get. Once you have confirmed that your CRT and flyback are good, you will have time to investigate other issues such as no reception on a certain channel.

The 630TS is one of my favorite TVs. This article has a link to the complete RCA service manual:

http://antiqueradio.org/RCA630TSTelevision.htm

Phil Nelson
http://antiqueradio.org/index.html

[Jonathan]

Thanks Phil for the reply. I always enjoy looking at your site, and you did a great restoration, not only the 630TS but your other radios and TVs as well. I have some very expensive Ecoline Contact Cleaner from Techspray, and it usually does a great job with pots and contacts. I'll be getting some DeOxit too. It's a few dollars cheaper, but probably just as good.

When initially recapping this chassis, I removed all electrolytics and saved them. I should have restuffed them, but I was stupid. I reduced the total amount of electrolytics by using a 120uF 450V instead of a C221B 40uF and C222A 80uF in parallel and an 80uF instead of the two C221A and C220A 40uF in parallel. I used terminal strips to mount the new electrolytics. It looks very messy, but I tried to fit everything underneath. The underside of this chassis is very messy-looking anyway, so I guess it kind of blends in. I also removed the power transformer and used heat shrink on all of the broken and cracked wires, thinking there was a short causing the problem and not the electrolytic I put in the wrong way. I put labels on all of the wires before I removed it.

Also, the power switch is kind of funny. During the "off" position, the contacts are closed, but should be open. Dirung the "on" position, they are open. This was a couple years ago when I last was working on the chassis, I never retested it since then. I have the AC directly connected to the power transformer for now. I know I sprayed the hell out of the switch and the switch worked as normal, but once it dried, it went back to being funny. Eventually I will fix this.

In the mean time I'll clean the tuner, pots, tube pins and sockets as you said, plus I'll be using naval jelly and metal polish to shine up the chassis.

Attached are pictures of the underside of the chassis with new capacitors installed. I replaced the electrolytics, the paper, one black beauty paper, and the rectangle mica, as well as the AC line filter capacitors.