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Well, after a few years, I got back to my 48-2500. As you can see above, I picked up a solid state TCG523 voltage tripler (equivalent to ECG523), and I finally tried it out.
It's important to ground both the "G" and the "CTL" terminal; otherwise the CTL terminal floats up to the HV and arcs over to the G terminal. The CTL terminal is meant to be connected to a focus control, which raises and lowers the "bottom" of the focus voltage divider. I'm not using the focus terminal for anything, so simply grounding the CTL terminal makes everything happy.
With the 1X2 voltage tripler, the HV varies between just short of 22 kV down to a little over 18 kV with the brightness high. With the solid state module, it seems to hover in the 22-23 kV range. As was reported above by TV Engineer, the focus drift problem with scene brightness almost goes away with the solid state module. Looks like the solid state module is going to get built into this set.
I also tried the trick of pulling out the DC restoration tube. That helps quite a lot naturally, although I certainly miss the nice DC restoration the set had before. But priorities being priorities, I'll take a more stable focus over DC restoration, so the DC restoration tube will also stay out.
Will give this thing a full going over, since I restored the chassis quite a few years ago, and I've learned quite a bit about alignment, etc., since then.
I have a resilvered mirror for this guy that I installed quite some time ago. Needs a little cleaning up, as does most of the optics after sitting in my dirty shop for a few years.
I also tested the three different TP400 CRTs I have. One is much better than the other two. Just in case you're paying attention, the nice bright one is the one I bought from you -- Craig R -- many years ago! Of the other two I have, one has huge spot size bloom at high brightness (sign of a dying tube; would be interesting to try a brightener on it), and the other has some kind of poor connection, which might be recoverable with some work on the socket pins. Anyway, the good one does not show obvious spot size bloom, even when it is very bright. So that's the one I'll be putting back into the set when I've gone over the chassis again and cleaned up the optics.
I think I have a buyer for this set, so I'm trying to get it into great shape before saying goodbye to it. No real place to display it in the house, and it takes up too much room in my shop.
Will post some pics sometime in the next few days.
Tom
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