hardware = KDS product # k-22mdwb model #22oow long story sh...

hardware = KDS product # k-22mdwb model #22oow

long story short ha ha ...
i received this monitor DOA in a trade . so i do not know the original circumstances but i have managed to repair it to a degree.

currently in order to get a picture on the lcd I have to unplug the video ribbon to the lcd turn the monitor on and then plug the video ribbon back in at which point the lcd receives a flawless picture.

If i don't follow the above process and leave the video ribbon plugged in the lcd doesn't power on at all not even the back lights. but as soon as i unplug the video ribbon the back lights come on. Then i replug the video ribbon and its flawless picture again.

any solutions?

Sounds to me like the ribbon cable is bad. I've had them go bad where the monitor would work only if you switched the output to that LCD after booting up, but if you rebooted, it wouldn't work (difference between a hard reset, and a software seek?).

Of course the inverter could be bad too, did you check w/ a bright light to see if the LCD is working, but the backlight is out (when it appears to not be working) ?

thanky you Navar.

yes i did insured the picture wasn't present when the back light is off with a bright light. also the problem is is present on all of the known good computers i have tried (3). also to be clear the video ribbon i was referring to is the one on the back of the lcd unit that plugs into the monitors board. not the cable from that plugs to the computer itself. I checked this ribbon for resistance on all wires and a resistance was present on all wires. I do not have a know good ribbon to test on this unit.
does that lean toward any other ideas?

yeah, I figured that was the cable you were talking about)

So is it simply a completely flat ribbon cable, or does it bundle? The ones that bundle have a greater tendency to go bad, but some of the completely flat ribbon cable/ flex board cable (copper trace on mylar sheet) literally have a life of less than ten cycles (meaning connecting/disconnecting)

Depending on the type of cable, consistant ohming isn't a reliable troubleshooting method (like the bundled ones especially) since shorts as well as opens can interfere with the bus.

It could be a bad component on the monitors i/o/control board interfering w/ proper startup, but that would most likely lead to a less than flawless picture when it does start up. I've got to admit my guess is still the interconnect.