I was hoping this was going to be yet another simple power supply
issue like the last two, but it was not to be.
This time I used my oscilloscope to check the +24DCV and +5V,
to make sure they were stable, and they were.
The backlight was not working, even with the +24V there, but the
"BLON" (back light on) pin was at zero volts, so I jumpered
this pin to +5V using a 1k ohm resistor, and the lamps turned
on, working just fine, but the screen was a blank black screen,
because the main board wasn't displaying anything, no menu
or anything.
So it's pretty clear it's a main board issue:
"BLON" (back light on) pin is on the white connector on the right most, bottom
corner. I measured some of the resistors in the lower right corner at +3.3V, but there
were also some areas that measured a weird +16V. WTF??????
But most of the advice here is for SMPS, inverters,
fuses, and caps, but not so much advice for fixing
main boards, so I ain't holding my breath, but just
in case someone knows something about this board,
I'm naturally all ears......
But it looks like it's Ebay time, yet again!
issue like the last two, but it was not to be.
This time I used my oscilloscope to check the +24DCV and +5V,
to make sure they were stable, and they were.
The backlight was not working, even with the +24V there, but the
"BLON" (back light on) pin was at zero volts, so I jumpered
this pin to +5V using a 1k ohm resistor, and the lamps turned
on, working just fine, but the screen was a blank black screen,
because the main board wasn't displaying anything, no menu
or anything.
So it's pretty clear it's a main board issue:
"BLON" (back light on) pin is on the white connector on the right most, bottom
corner. I measured some of the resistors in the lower right corner at +3.3V, but there
were also some areas that measured a weird +16V. WTF??????
But most of the advice here is for SMPS, inverters,
fuses, and caps, but not so much advice for fixing
main boards, so I ain't holding my breath, but just
in case someone knows something about this board,
I'm naturally all ears......
But it looks like it's Ebay time, yet again!
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