Toshiba RPTV help needed

Educated guess: If you suspect convergence ICs most of the other anomalies may be linked to the convergence processing. I would replace those first, find a service man alignment and go from there. You gotta start somewhere.

Don't worry about the geometry, just correct the convergence problem and all will be well..

I pulled the power/convergence boards out of both today, and could see nothing wrong. The thing has STK392-020 convergence ICs, or at least had. One (the same location on both boards) has been replaced with an stk392-040. I checked all the resistors, as i understand that convergence IC fault results in burnt resistors, but none test open, actually everything seems to be fine. There are burnmarks on the power supply board around a diode on both power supplies, but the diode isn't shorted and neither are any of the resistors around.

Is there a definitive way of testing the convergence ics themselves? I suspect that the previous owner tried to fix the projectors but onyl replaced one of the two ics and then wondered why it didn't work... or somesuch... so I'd like to test the ics themselves... 4 of these things would be a slight waste of money... (Can get them locally and if I buy 3 or more I get a discount, but wouldn't like to buy them if it turns out they're not at fault...)

To discharge the CRT High Voltaage, use a pair of grounded pliers holding a hatpin in the pliers and go thru the rubber, or better yet go between the glass and the rubber. Can't help with the convergence.

I know how to discharge a crt, but since these are glued in, I thought there may be a trick to it like simply de-attaching the HV line from the flyback and grounding it there instead of having to remove every single cup just so I can get out the other board aswell. Thing is I didn't want to tear out the suction cups, but oh well. (And no I'm not plannign to mess around too much with the video board, but since I'm doing arcade restorations here, I clean even the pcbs.)

Anyways... I took the plunge... 4pcs of STK392-040 and some other parts I've been waiting to get are on their way... this wasn't a cheap order... 110 USD with next day shipping. (Four STKs, one hantarex flyback and a handful of capacitors... pricey...)

We'll see what happens when I replace the ICs tomorrow.

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Keep us informed of your progress (or lack thereof).

Unfortunately it's a lackthereof...

Since these two projectors share the same power/convergence output boards, I replaced the convergence ics on one, and tested both with it. Also replaced -all- electrolytics on the board, checked all the resistors, even replaced three caps in the powersupply section that seemed dodgy.

-No- change whatsoever. Since I don't have a remote yet I can't test if convergence adjustments actually work. I checked power supply outputs on the resistors near the STKs, and +35,-35,+15,-15 volt supplies all check out to within .1 volts. Checked 12 volts on the power board, it seems slightly low, but since 12 volts is usually unregulated, I'm pretty sure 10.8 volts is fine.

At this point either the STKs are not getting good control signals, or the problem lies on the deflection board.

Any tips/tricks you guys have? Maybe I forgot about something? I hear pico fuses mentioned a lot, but could not for the life of me find anything remotely resembling a fuse on the convergence output board. The only fuses I found were on the powersupply board and they all checked fine.

Does anyone perhaps work in the industry and have schematics for this thing? I'm pretty sure Toshiba used these in commercial RPTvs too. Also does anyone have any documentation on how to calibrate the output levels evenly on these things?

Any and all help would be appreciated. I'm pretty steamed at toss> >

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