LCD woes - test-drb@ccmp.vtda.org

2 Sep 1998

HGC _could_ stand for Hercules Graphics Controller. I don't know.
The display... are you sure you haven't shorted anything with solder?
Have you tried using a VOM in O mode to directly stimulate the display?
Touching it to various pins should get various lines to appear.
...
 'fixing' my portable '286 box with LCD
display (which I think is  _barely_
...
 classic).

The cable leading to the display had had three of its wires pulled out,
and I figured that this was the reason for the very weak and grungy
display.

I managed to solder little bits of wire into the holes and solder the
stray wires from the cable onto those, but then I realized that I  couldn't
...
 plug the thing in anymore as the holes (from the
underside) had filled
with solder. :/

And I also realized that my solution was a bad one because the  protruding
...
 wires would short against the metal frame that holds
the LCD panel in
place.

So I used the connector from the C64 keyboard instead.

Anyway, I got the cable rebuilt.  I've tested it with the multimeter  and
...
 all the wires make contact and go to the right places.

But now I can't get any kind of display from the LCD panel.  It doesn't
light up at all.  It looks like it's totally dead.

I put a monochrome display adapter card in the machine, and it will  boot
...
 up with that and display fine on a monochrome monitor. 
So the machine  is
...
 _mostly_ OK.

I'm not sure the power supply is OK, though.  It squeals now.

So basically, I've turned an ill-looking display into a dead display,  and
...
 for some reason a healthy power supply is now sounding
sick.

Bleah!

Anyway, the machine has a special card in it for driving the LCD panel.
It is labeled "LCD & HGC CARD".  What is "HGC"?  It has an
external  9-pin
...
 port on it and I tried plugging the monochrome display
into it, but the
picture was all distorted so I figured it was using a different  frequency
...
 or something.  The cursor comes out about an inch wide,
and none of the
craracters are recognizable, possibly just from overwritten numerous  times
...
 in the same scanline.

I don't know where I'll go from here.  I'm just taking a breather
before continuing.  I wanted to be rebuilding the TS1016 RAM pack by  now
...
 instead of still messing with this damn PC. <s>

Oh, and BTW, I electrocuted myself last night when I touched some  exposed
...
 wiring going to the LCD panel.  It surprised me that
there was that  much
...
 juice going through there.  My thumb and forefinger are
still tender.   But
...
 the display was still working at that point, and
looking much sharper  than
...
 it had been.  But the machine wouldn't close up
properly because the
connector was too thick and that's why I went back in today, just to
reverse the cable so that the big fat Commodore connector was on the
inside instead of on the LCD panel end. (Which meant pulling the  connector
...
 apart and rebuilding it the other way, just so it would
fit in.)

I haven't crossed any wires, I haven't plugged anything in backwards,  and
...
 I haven't dropped anything into the machine, so I
don't know what I've
done wrong.

<s>

Doug Spence
ds_spenc(a)alcor.concordia.ca
http://alcor.concordia.ca/~ds_spenc/

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