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maiser
Joined: 30 Mar 2009
Posts: 5
Location: Norway
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| Posted: Mon Mar 30, 2009 7:12 pm Post subject: Barco 801s Vertical deflection and Sync physical malfunction |
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Hi. After cleaning and re-soldering this card and its sub-board, two resistors got broken when the projector was plugged in again. At least those two resistors where broken(i found out by foul burning smell, typical for electrochemical's when burned), for what i know something else could be broken as well. I replaced these resistors, which i found out are safety resistors by the way, but they broke again. So its obvious some other component or components are malfunctioning. Does anyone know what might have gone wrong when these safety resistors get burned at start: SR1 and SR2. I need some directions from more experienced people.
I was so lucky to get hold on a friends card for a while until i find the error and fix it. The card i got was quite similar so i tried testing my sub-card with the one that i knew worked, and the result was it worked as well. In other words, the sub-card is OK while the main in not working for whatever reason.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Tue Mar 31, 2009 5:20 am Post subject: |
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Burning SR1 and SR2 indicates that +9V and -17V lines have short somewhere. It could be to ground or between those lines.
First check your re-solderings carefully, try to find shorted traces.
Those lines are used only for three vertical output drivers TDA8172 (BD801s), but there is also some filtering caps and diodes...
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maiser
Joined: 30 Mar 2009
Posts: 5
Location: Norway
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| Posted: Wed Apr 01, 2009 5:46 pm Post subject: |
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| Ile wrote: | Burning SR1 and SR2 indicates that +9V and -17V lines have short somewhere. It could be to ground or between those lines.
First check your re-solderings carefully, try to find shorted traces.
Those lines are used only for three vertical output drivers TDA8172 (BD801s), but there is also some filtering caps and diodes... |
Thanks for responding. So, basically said, it should be easy to find the source of malfunction? Either way i will try looking for shorted traces(again).
By the way, you mentioned BD801s, that is the Data model i presume. Is this any different on the Graphics model?
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maiser
Joined: 30 Mar 2009
Posts: 5
Location: Norway
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| Posted: Sat Apr 04, 2009 5:22 pm Post subject: |
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Now i get this very nasty noise when i try starting the projector and the error code comes blinking after a while. I didnt find any shorted traces btw.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Mon Apr 06, 2009 7:56 am Post subject: |
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| maiser wrote: | | Is this any different on the Graphics model? |
Vertical output driver chips could be different, but don't know for sure. Don't have schematics for Graphics.
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maiser
Joined: 30 Mar 2009
Posts: 5
Location: Norway
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| Posted: Mon Apr 06, 2009 9:51 am Post subject: |
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| Ile wrote: | | maiser wrote: | | Is this any different on the Graphics model? |
Vertical output driver chips could be different, but don't know for sure. Don't have schematics for Graphics. |
I found them to be 3 TDA8172's. I tested each of them with diode-test on a multimeter and they seam to be acting normal, but im not sure.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Mon Apr 06, 2009 10:47 am Post subject: |
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Have you compared power line resistances (SR1 to SR2, SR1 to ground, etc) to working board?
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maiser
Joined: 30 Mar 2009
Posts: 5
Location: Norway
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| Posted: Mon Apr 06, 2009 5:19 pm Post subject: |
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| Ile wrote: | | Have you compared power line resistances (SR1 to SR2, SR1 to ground, etc) to working board? |
No, but i will now.
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