Starting work on the Sylvania 7140M

[Eric H]

Well it's 4:45am and I couldn't sleep so I thought I'd post a little more on the progress.

Another tube that tube testers really can't tell you much about is the 5U4, both of the ones in this set checked good but weren't really.

They are wired in Parallel in this set so you can pull one out and the set keeps on working, I pulled the first one out and it kept working fine, a little picture shrinkage and the sound dropped a bit but nothing dramatic.

I put the first 5U4 back in and pulled the second, well, a huge difference, the picture shrank and dimmed almost to the point of disappearing!

I scrounged up another tube from another set and tried it, now the picture was stable on either 5U4 but a little better on the replacement tube so I scrounged another one, now it worked well on either tube by itself.

This also increased the High Voltage substantially, it's running 12k with the picture adjusted to normal brightness, it still drops if I crank the brightness way up but I believe it has enough oomph to try the 17" tube in it.

The Horizontal is working pretty well but it still drifts after a while so that it gets a ghosting or fold over creeping in from the left side of the screen after a while, I can adjust it out but it comes back. I still need to run the setup but there may be a resistor drifting a little after it gets hot, I'll poke around more tomorrow and see what I can find, I'll try the big CRT also, I'd like to see how it looks even though it checks good.