Broken 20.1" UXGA LCD monitor IBM L200p
Upper left corner had this label.
As is shown above, it said,”うつりません or No picture.”
Originally it was an expensive monitor priced 178,000 Yen in Japan when
released several years ago. It was targeted for a CAD or a professional
use and was a UXGA (1600X1200) monitor. It provides a wide view angle
with good picture quality using a IPS LCD panel. But due to the lack of
engineering skill of the OEM company which designed and manufactured
were many L200p monitors for a CAD use in my company and they were
failing next to next. I did not have any chance to see them repaired since the
broken one was exchanged quickly to a new one or a factory repaired one.
I found the L200p the other day at a PC shop in Nagoya tagged 2000 Yen
with a label “うつりません”. As I loved junks and my next project was to fix this.
As I checked it at my work bench pushing the power button on, monitoring
the secondary DC line by a oscilloscope, It went up to 2.5V DC and then
dropped. Some protection has worked and the DC did not fully rise up.
There must be a short circuit somewhere in the printed circuit board.
Checking components, I found one of FET arrays for the back light inverter
(indicated by a red arrow) had extremely small resistance between the source
and the drain. The name of the FET array was P2103NVG. I did not have
this one in my parts box but I had a FET array which is almost the equivalent
named AP4501GM and I trid to use it as an experiment. The result was OK.
Look at the photo below.
Now it powered on and you can see IBM logo. As I check the voltage of
the drains of all FET arrays, the peak voltage is as high as 30V which is
the absolute maximum rating voltage of P2103NVG. It is natural that many
ThinkVision L200p have failed in the market.
As I search the net, there are many other posts regarding ThinkVision L200p
with broken P2103NVG. I will be selecting and using some other FET arrays
which withstand higher voltage with smaller S-D resistance.
Anyway my another project will be completing soon.
