CurtPalme.com Home Theater Forum

[barclay66]

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In your schema
led 8 (red) ever OFF
led 9 green) ever OFF
led 10 (green) lit but NOT BRIGHT

[barclay66]

Hi,

Looks like You might need a new EHT board and potentially a new Quad. One of them could have a short which kills that resistor in the main SMPS.

As soon as this is fixed Your HV should be back. Then You could address the missing CONV voltage. The projector should work even though it's missing.

Regards,
barclay66

[Curt Palme]

If I'm not mistaken, the convergence voltage shuts down when that resistor is open. I remember chasing that one for a few hours once...

[Curt Palme]

If I'm not mistaken, the convergence voltage shuts down when that resistor is open. I remember chasing that one for a few hours once...

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The issue is definitely found (thank you Barclay66): today I tried to replace the fusible resistor with another and it was burned immediately.
So replace simply the resistor is useless because I have to find the real cause of the fault somewhere of the projector.

[winny]

Which position in the schematic is the resistor?

[Curt Palme]

oK, now pull out the EHT board, replace the resistor again, and see if it blows again without the EHT board in place. If not, you`ve found your problem!

[Curt Palme]

oK, now pull out the EHT board, replace the resistor again, and see if it blows again without the EHT board in place. If not, you`ve found your problem!

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[Curt Palme]

Ok, try the same thing and pull out the G2 board, and then also try it with disconnecting the white motherboard connector from the quadrupler.

[Curt Palme]

Ok, try the same thing and pull out the G2 board, and then also try it with disconnecting the white motherboard connector from the quadrupler.

[Decibel]

I can try when will buy other fusible resistors.
Now I haven't other.

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It's impossible to find these fusible resistors, 0.1 ohm 1/4w.
Help me!

[winny]

Though-hole is non-standard these days and even back then 1/2W outnumbered 1/4W 100:1.

The closest I could find at Farnell is 0.22 ohm. You can wire two in parallel but then you might as well move to 1/2W 0.1 ohm.

http://uk.farnell.com/jsp/search/browse.jsp?N=215514+110051225+110034967+110053524+110097942+110101913+110082157+110003811+110102927+110062552+110003321+110079829&No=0&getResults=true&appliedparametrics=true&locale=en_UK&divisionLocale=en_UK&catalogId=&skipManufacturer=false&skipParametricAttributeId=&prevNValues=215514+110051225+110034967+110053524+110097942+110101913+110082157+110003811+110102927+110062552+110003321&mm=1000194|110005225|110109935,1000635|110033943|110003811,&filtersHidden=false&appliedHidden=false&autoApply=false&originalQueryURL=%2Fjsp%2Fsearch%2Fbrowse.jsp%3FN%3D215514%26No%3D0%26getResults%3Dtrue%26appliedparametrics%3Dtrue%26locale%3Den_UK%26divisionLocale%3Den_UK%26catalogId%3D%26skipManufacturer%3Dfalse%26skipParametricAttributeId%3D%26prevNValues%3D215514

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Thank you Winny.
Simple but great help.

[winny]

Sorry, I was not clear in my statement.

If Barco selected a 1/4W resistor in order to fuse at a certain current (not a bad design but far from optimal design), you will defeat this purpose by choosing two 0.22 ohm 1/4W in parallel in the same manner as choosing a 1/2W 0.1 ohm resistor. Considering the amount of spare parts you have, I would have chosen the 1/2W 0.1 ohm and hope that Barco didn't make this choice.

If you can share the position (RXX) of the resistor in the schematic or printed on the PCB itself, I can give you more help.

[Curt Palme]

Another way to look at it is to just use a 0.1 ohm 1/4 watt resistor. It seems like you have a dead short on the load side of that resistor, causing it to blow instantly when you power up. I think you could put in a 1 watt resistor, and it too would smoke almost immediately at turnon at this point (but DON'T do that!)

Point is, right now it doesn't matter exactly what resistor you put in there, as long as it's under 1/2 watt, it will blow right away until you find where the short it... Once you get your picture back, then worry about finding the right resistor for long term protection.

[Curt Palme]

Another way to look at it is to just use a 0.1 ohm 1/4 watt resistor. It seems like you have a dead short on the load side of that resistor, causing it to blow instantly when you power up. I think you could put in a 1 watt resistor, and it too would smoke almost immediately at turnon at this point (but DON'T do that!)

Point is, right now it doesn't matter exactly what resistor you put in there, as long as it's under 1/2 watt, it will blow right away until you find where the short it... Once you get your picture back, then worry about finding the right resistor for long term protection.

[Hulio]

Domenico,
According to Greg, the resistor R134 could get blown from a convergence cap short ( 19V rail ).
Read the last sentence from post nr. 25
http://www.avsforum.com/t/952234/barco-1209-next-repair-step

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[barclay66]