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Toshiba convergence 42H81
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Phils
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PostPosted: Thu Jul 05, 2007 8:38 pm    Post subject: Toshiba convergence 42H81 Reply with quote

Had this set since new, a few weeks ago the blue convergence failed: blue will adjust up and down but not side to side.

I replaced the convergence board yesterday and the problem remains unchanged.

Can someone here point me in right direction to repair this? When I swap the convergence boards back I'll be looking closely for burnt resistors (if I can find the amp circuit that the convergence signals pass thru on the way to the deflection yoke).

Is there anything else I should be checking?

Phil
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cory
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PostPosted: Fri Jul 06, 2007 10:48 pm    Post subject: Reply with quote

convergence ics are stk392-110.only get them from toshiba or problems with aftermarket.also check resistors under heatsincs.
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Sat Jul 07, 2007 2:35 pm    Post subject: Reply with quote

You replaced the whole signal board and still have a problem? #23786714
PCB SIG PD0073E.
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PostPosted: Mon Jul 09, 2007 3:59 pm    Post subject: Reply with quote

minnie wrote:
You replaced the whole signal board and still have a problem? #23786714
PCB SIG PD0073E.


Actually, the board I replaced was 73786221 PCB DIG PD0078A and the problem remained unchanged.

But, Minnie, some of your ealier posts that I found directed me to the STK-392-110s and the fusible resistor for each. Then cory mentioned the same parts with the added caution of getting 'pure' Toshiba parts, so ordering the parts is today's project.

Thanks to you both and I'll post the results back after I relace both ICs and both resistors (might as well, they're cheap and the 'good' IC is just as old as the bad one).

Phil
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PostPosted: Mon Jul 09, 2007 4:03 pm    Post subject: Reply with quote

OOPS... p/n I replaced is 23786221

Phil
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Mon Jul 09, 2007 10:09 pm    Post subject: Reply with quote

Anonymous wrote:
OOPS... p/n I replaced is 23786221

Phil


That looks like the digital convergence generator. Put new ic's in and put back the original DCU.
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Phils
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PostPosted: Tue Jul 10, 2007 8:12 pm    Post subject: Reply with quote

Minnie,

I've studied the schematics extensively but cannot tell which IC controls the Blue Horizontal convergence. Yes, I'm planning on replacing them both but would like to keep the "good" one for a quick temporay fix if/when this happens again.

Does anyone know which IC controls which convergences?

Phil
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Tue Jul 10, 2007 10:20 pm    Post subject: Reply with quote

Shitty print.
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Phils
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PostPosted: Tue Jul 10, 2007 11:23 pm    Post subject: Reply with quote

minnie wrote:
Shitty print.


If you mean my schematics, you are RIGHT ON! However, the schematics are better than the Japanese-to-English translations.

The BH, BV, RH, RV, GH and GV all leave the convergence board and the lines combine into one and when the separate at the amps, there's no designations as to which amp controls what action.

IF there's a fusible resistor blown I'll be able to figure out which is which but if the amp went south without blowing a resistor, I don't know a way to easily determine which amp is the bad one.

Your help is absolutely appreciated too. Minnie, I think I've read almost every post you've made about convergence and Toshibas (BEFORE I first posted). I'm lazy tho and chose to replace the convergence board FIRST instead of the STKs simply because I mistakenly believed it'd be easier -- just unplug a board and plug in a new one. I didn't know until too late about the shielding can. Of course, now I think I'll be able to swap boards back pretty quickly.

I hope your place in 'hell' is one of the better perches!

Phil
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Tue Jul 10, 2007 11:54 pm    Post subject: Reply with quote

It's a shitty print. All the yolk return resistors should be between 1.2, 1.8, & 2.2 ohms. Just look for obvious discoloration. If you put the original DCU back in the colors should be pretty damn close. When in service mode if you can't adjust a color a certain way, then it's time to hunt for bad resistors. The resistors should be in groups. It's pretty esay to spot the bad one/ones.
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