Jonathan
04-08-2010, 03:44 AM
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
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