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Changed a dead green crt with a new Sony 07ms I got from someone on ebay. Powered up projector and got the wonderful smell of burning electronics! Projector went into V inhibit mode.


Tracked it down to 2 burned resistors on the green power deflection board, R81 and R101. These are listed as 1 ohm 0.5watt metal film resistors with an exclamation point on the schematic.


Anyone know if they need to be flameproof also?


Anyone know why they would die like this? I checked the transistors, diodes and the resistors in the circuit and they seem good. The deflection coil reads the same dc resistance and the other two (the red tube and blue tube coils).


Does this mean something is wrong with my new crt? or does something have to be adjusted to match the new tube and is maybe out of range with the old tube's settings?


Any ideas?


Thanks,

Ken
 

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I just had one of those as well. I'm not in front of the manual, but if it's the same resistors that I think they are, they're current limiting resistors for the convergence output transistors.


I had shorted transistors that took out the resistors.


You might look for a new board, I think you need the -07 version, and I just used my last one until I repair this one.


Curt
 

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Thanks Curt for responding!


I temporarily replaced the resistors with 1 ohm 1W normal metal film resistors until I can get flame proof ones, 0.5W. I wanted to see if they would blow again, or if the projector would come up.


Well, the projector did come back up (no v inhibit) but the green tube is acting just like the one I replaced! It is overly bright again, though I don't see any scan lines, and I do see the correct image.


Checking the cathode voltage on the green neck board (voltage output module) and trying to adjust it to be 140V via R5, it seems stuck at 147.8V! On closer inspection, R25 (100 ohm, 1W) is cracked in half. Also R24 (560 Ohm, 10W) is oozing some translucent black goo that has hardened.


I need to replace R25. Electrohome lists this as Resistor Chip. Is this just a regular ceramic surface mount resistor? Or with it listed as a safety component, is it some special type like flameproof or metal film, etc.?


R24 still measures as 560Ohm. Should I replace it anyway? Is this the famous large resistor that fails and is hard to replace?
 
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