Hello! I just go approved to post, and I'm here for help on a recent acquisition of mine.
Sorry ahead of time for the wall of text and several pictures, but I figured it would be best to just give all the information I think relevant before throwing this problem out to you all. Any help is appreciated.
It's a 1974 RCA XL-100 floor console television, chassis CTC-68UE. It was practically free. Cabinet is beautiful, CRT is very strong and produces some brilliant colors, but the chassis... There's something very wrong.
EDIT: The Sam's is set 1517, folder 1.
First and foremost: One of the colors is missing. I've already diagnosed this, the kine driver for blue was dead. I checked this by swapping it with the green driver and lo and behold, no more green. I ordered an NOS kine driver and that should fix that problem.
It seems the drive transistors work extremely hard and don't have very large heat sinks on them. I'm thinking of either replacing the transistors with better rated parts or getting larger heatsinks for them. Would this be possible / appropriate? I don't care about originality, I just want the set to work and to make it last as long as I can. Unfortunately, the transistors are unmarked on all 3 boards.
The kine driver boards are RCA model MAD001.
Linked below are pictures of a red-blue-green color bar test and the offending kine driver module. Don't mind the shutter speed of the camera.
Next, the background is always red. No matter how I adjust the front and rear controls (Have not touched convergence controls or anything internal yet, I don't have the Sam's right now. I ordered it, though.), the background is always red. I've seen this same pattern generator on many sets, but I'm new to color and solid states. Background should be black. Thoughts on this?
Lastly, the big problem. The tuner is completely screwed. I'm using a Leader LCD-388 video generator to put these patterns on the screen. It can broadcast on channel 5 or channel 6. If you look closely... You'll see I'm picking it up on UHF channel 49. I also have a VCR attached, which is broadcasting on channel 3 or 4 but does not appear on any channel at all. The audio comes through channel 2. Fine tuning does work but does not affect the picture not coming through. Pressing AFT causes it to completely lose the signal when tuned to the LCG-388. Turning AFT back off brings the picture back.
What is going on with this tuner? I don't care about UHF channels at all. I really only need channel 3 or channel 4, I can use a VCR to tune every other channel there is, but I can't get any output from it at all! I know it works, I've gotten a good picture on my Predicta with the same VCR on channel 4.
How do I adjust a tuner? I don't know what model the tuner is, so I've been struggling to find a replacement. Could this be an IF problem instead and the tuner is actually fine?
If it helps any, there is almost no static on VHF channels but all UHF channels have the typical 'snow' on the screen.
I know it's possible to add a composite input to this set, but how difficult would it be? I'm not sure what the input level is or where to feed it in. I have removed the video board, but I'm a bit scared to start poking around with the scope, since I don't want to damage anything. It's a very tight space to stick a probe into.
Below is a picture of the tuner assembly and of the video board itself.
