Questions on convergence...

On Saturday 12 August 2006 08:00 pm, John Boffemmyer IV wrote: I've done that sort of thing, on TVs, and what you describe there ain't old. TVs that were still using all vacuum tubes when I worked on them back in the days I had my shop -- now they were OLD! Convergence used to be a real PITA, because you had static convergence that was done by moving magnets on the neck of the CRT (not to be confused with the purity magnets!) and then you had dynamic convergence, which was typically 12-16 separate adjustments, all of which interacted to some extent. Stuff has come a long way since those days, and a lot of it is compensated for by the factory attaching the deflection yoke and some very small (and weak) magnets to the CRT and gluing everything down. The design of the face of the tube has moved away from the old dot triad to triads of small stripes, which gives you the advantage of the "Trinitron" design without the expense of that tube. If this came on all of a sudden rather than gradually, it's possible that the glue or other goop holding one or more of those magnets in place has given way and they've moved -- looking the thing over with a strong light and a magnifying glass would perhaps reveal this and allow you to put stuff where it belonged. If it did come on gradually then there's probably some circuit component that's shifted over time and will need to be replaced. I used to try and fix monitors. The last time I had one that I wanted working I ended up tracking down some guy in the area who would work on them, taking him 3 or 4 of the monitors that I had around, and telling him that he could keep them if I got the one fixed that I wanted. As it turns out he didn't fix it right, and I've not felt like being bothered to go back there and hassle it since then. I did open that one up, but there was no way I was going to attempt that repair. <shrug> The other thing is, to do a proper convergence needs a signal that's going to give you a stable pattern, although I suspect that's easier to do with a computer driving it than not, I had to buy a little generator for TVs back when, which I still have, but it's RF output only and limited in terms of what frequencies it'll deal with. You'd need something that would deal with the frequencies you're operating at. I know of one guy who actually went out and spent the money on such a generator, and it's been several years since I talked to him, I don't even know if he's still in business or not at this point in time. Monitors are apparently moving into the "not worth fixing" category any more. And I just saw one offer of a couple of them on a local freecycle list. And didn't go for them as I have pleny of them on hand now... -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, a critter that can be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin