Hi. I have a 50HX70 Toshiba here. Replaced both convergence STKs, which fixed many evils. However, the red is bowed well up at top and well down at bottom. Left and right is fine. Tried another new STK for the red vert, does the same. All the resistors check good, and I have control of the convergence through the menu, but it does not have the range to bring the red in line with blue and green. Just need an inch more. Will continue my checkings, but wondered if anyone had seen this before. I feel I'm missing something simple here.
This looks exactly what I would have posted, I have one doing the exactly the same thing. It first had bad green conv, I mean really out on the green, Found one of the 1..8 ohm open, checked all the caps around, visually that is... didn't pull any... all looked OK... found one of the STK mods shorted, ordered a set of the 1.8 ohm flame proofs, all six, cheap enough. Also ordered one of the STK's from MCM, problem fixed, so I thought. About a week later customer calls back, went out, noticed that one of the 1.8 ohm resistors that I replaced was 'toasting out' checked it, it read around 2.2 ohms... so... I ordered both STK's figuring, that, perhaps, the mate for the other side was toasted as well, "I don't have a schematic for this beast' but, followed the traces back, looks like the 3 amps in each module cover the three colors in some sort of push pull arrangement. Well, after replacing both units the problem still persists. I haven't been out yet to check, customer lives a ways out and I really don't want to try to lug the entire unit back to my shop, figure to would do more damage moving it. I've been just pulling boards and bringing them back to my shop. can't really fire them up here at my shop, so, it is just go over them with my meters. The one I have will run fine for about 5 minutes and then begin to drift out slightly on the red, top left side of the screen. I did notice that the STK's run pretty warm. I did the convergence from the remote, the one that comes up with the
1 thru 9 on the screen, set also has a auto focus button, not sure how that works with the CPU, might be that we have to put the unit into some sort of primary convergence mode. I've heard that there is some sort of overlay that goes over the screen and that there is a 'secret' command string that you enter into the remote to get it to go into the crosshatch pattern. Perhaps this needs to be done to lower the quiescent bias currents of these circuits. I feel that perhaps it is just in need of better alignment. I've seen convergence ckts in some commercial cameras that would do the same sort of thing, run really hot if not aligned properly, this really goes back when they had literally dozens of control pots to do the alignment. Do you know how to get this into the secret service mode? Why am I replying at 4 in the morning, just had jaw surgery and couldn't sleep... one good thing, no cancer,
Take care,
Markus
of 1.8 ohm resistors and On Mon, 26 Sep 2005 11:48:32 -0500, wrote:
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