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I have a CTX-3030 repair I?m working on that has a backlight that doesn?t come on. It originally had a torn flex cable to the front panel but I fixed that well enough to test the detector- very thin wires crossing the cut and any flexing breaks them off the kapton flex. I need to determine if the backlight on the display is bad or if it is a driver issue on the board. What is safe to drive the backlight with externally to test it? Or what should I see on the backlight ribbon cable?
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if you have an adjustable bench supply try .5v and just increase in very small increments, if i had to guess it would be between 1.5-3v, some displays use really small voltages.
not like the old days when they had those tubes. -
Add a series resistor to limit current, maybe 1k.Comment
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Thanks guys, exactly what I had planned but wanted to check…Comment
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He has some very interesting videos, but on this one he left out the good part - he said by messing with it he got rid of the lines in the display! What did he do? First I’ve heard that you can do anything to fix that.Comment
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hello, first you must check if the backlight is actually burned or if it comes either from the on/off button of the backlight, or from the tuning , see pic
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What is it?
.759 in diode test mode 1 direction.
~.5v across it in circuit.
no continuity resistance mode.
markings:
qpwbh2291tpzz
cpwbm0075tpzz. And ?fx?
Did not light with 4.5v li-ion cell and 1K resistor.
Check the chip to the right of C122. This drives the backlight. Is it an inverter circuit for an EL panel?Comment
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Chip marked BZS261 C3PC.Comment
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It’s a Sharp display and has a LED backlight. Six leds in series. Test with a 220 ohm resistor and 20VDC. So this means my driver board is bad…. Could Hotwire it…Comment
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