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RVonse
Joined: 09 Mar 2006
Posts: 3152
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| Posted: Mon Sep 05, 2011 2:44 pm Post subject: Output convergence board compatablilty between BG808 an 12xx |
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I have a Barco 1208 converted with 9" Ampro tubes. Convergence has always been a little more challanging because the tubes are spaced further apart then 8"ers. I have been running for several years on the original convergence board but all a sudden when I changed out the red tube I found I had to adjust convergence even more. Most likely I did not get the tube in quite the same angle.
Anyway I blew out the convergence output board on red/green (blue has never been an issue) and now have blown out my only spare in less than 2 weeks. Last night in a desparate hope to getting back going, I put a BG808 output board in my 1208 chassis. It has the STK chips instead of the mosfets used on the older board. To my surprise the board not only worked but convergence is actually better than before and almost all the red/green adjustments are in the 50% range now.
But my question is whether I should leave it this way. It looks like the 808 board was meant to have a fan which I no longer have in the 1208 chassis. Will this board stay cool enough? So far it appears the chips staying pretty cool after about an hour and they seem to have more horsepower than the mosfets did anyway.
Is it normal for a convergence output board to blow if convergence is overworked anymore?
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Curt Palme
CRT Tech
Joined: 08 Mar 2006
Posts: 24396
Location: Langley, BC
TV/Projector: All of them!
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| Posted: Mon Sep 05, 2011 3:29 pm Post subject: |
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Leave it. Seems that on occasion, there's a good (or bad ) match between the output and driver board, and I think that's what you had at first.
You can use either the chip or MOSFET output stage on either the 808 or 1208 without any issues.
Yes, it's relatively common for an output stage to smoke on the MOSFET style. Two so far charred the board so much I had to throw the board out.
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RVonse
Joined: 09 Mar 2006
Posts: 3152
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| Posted: Wed Sep 07, 2011 9:17 am Post subject: |
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Thanks for your response Curt.
I replugged the wiring from the red focus coil to the motherboard just to make sure that was not loose. Watched a couple of movies on it now. Everything red/green is pretty much in the 50% range and so far still running good with no failure yet.
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