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Hi, here is a bit of an update on this TV... I got curious and started poking around the chassis and decided to temporarily put in some 100uf filter caps in the power supply and change the boost caps just to be safe and attempt to fire the set up.
Using the variac I wound the voltage up I could hear things rustling and noises from the speaker, then the vertical kicked in, so I wound the variac up a bit more and there was an odd squeal from the flyback, glanced at the 1B3GT and it was lighting up a pretty purple inside! Hmm...me thinks that tubes a bit gassy so I put another good one in and powered on again and this time we had EHT but no picture or even a raster.
Checked voltages around the video stages, all appeared to be ok there and the cathode volts to the crt was within spec. I turned the set off to see if anything would happen and as the EHT collapsed there was a small bright image on the screen....ah-ha... Seemed like the CRT was being cut off. I didn't get much further that night as was very tired.
Looking at it again with fresh eyes I checked the grid volts on the crt base and as the circuit stated this should have been at least 80-90 volts on pin 2 and varies with brightness.
Mine measured around 40 volts on the grid... We have a problem here!
Started checking things in this part of the circuit the resistors in series with brightness pot and a 100k to ground which checked ok but there also were some 0.1uf coupling caps which turned out to be leaky, replaced them and I now get a picture although its lacks width and the verticals all up the creek, but at least the TV is now functioning and its producing sound and a picture of sorts, so a good start so far.
My next move is to investigate the lack of width, the picture is not very bright and the EHT is lower than it should be at full mains voltage so will look into that and then will sort out the vertical which may improve when the width is sorted.
There are a lot of wax paper caps in this one so replacing those will only improve things no doubt and I can bet there are a few resistors that have drifted way off also.
That's all for now. Stay tuned...
Cheers Glen.
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