dave@dms3b1.uucp (Dave Hanna) (04/29/91)
HELP, Please!
I just finished all the mods for John Milton's HD2 board (fortunately,
on a spare system). I got it all lashed back together, powered it on,
and ... nothing!
The screen came up with a pattern mostly of alternating bars and spaces
across the screen. There were 45 across, and they alternated in opposite
phase on each line, i.e., it looked something like this:
__ __ __ __ __
__ __ __ __ __
except that the rows were a scan line apart instead of a character line.
I'm assuming that that was just the power on pattern in the RAM, and that
it never made it far enough in the power-up code to get to clearing the
screen.
The green LED was on solid, and I don't think any of the others were on at
all.
I unplugged all the plug-in connections from the HD2 board to the mother-
board, and there was no change.
I've pulled it back apart, and rechecked for solder bridges, etc.
I have not yet double checked for wrong connections, but I will as soon as
I finish this.
The only real difficulty I had with the mods was in unsoldering Pin 3 of
the PAL at 14M, and it's possible I had that chip too hot for too long.
I don't know what else it controls.
Whatever is wrong is affecting basic processor operation, not just the
disk circuit. It's never making it anywhere near far enough to try to
access the disk.
Any help would be greatly appreciated. PLEASE reply by E-mail, as I'm
frequently out of town and get behind on news.
Dave Hanna
--
Dave Hanna, Infotouch Systems, Inc. | "Do or do not -- There is no try"
P.O. Box 584, Bedford, TX 76095 | - Yoda
(214) 358-4534 (817) 540-1524 |
UUCP: ...!letni!dms3b1!dave |