Hey all,
I suspect it's super unlikely but I'm hoping to find someone who might have a non-functional or donor HP LogicDart that I can salvage the LCD from. If you have a fully working LogicDart and you're willing to sell it (I won't cannibalize it), let me know as well.
I took mine out of its protected storage case only to find the LCD seems to have broken. Surprisingly it still "works" but the display is very hard to read with the purple blob syndrome.
I'm 99% it's a custom LCD that's 131x64 resolution, derived from the one used in the HP48 calculators but a different display without the calculator's annunicators. I could reverse engineer the display controller, create an FPGA design to drive a modern LCD (128x64?) but that'd be a huge time investment on this. This unit actually means a lot to me, I was fortunate to get it almost 20 years ago and I'm really saddened to see it in its current state.
I guess the LCD is fine. Just replace the LCD polarizer.
Search how people have done it with Tektronix THS 710/720/730 scopes on this forum.
Upd: you can also google for "nintendo lcd polarizer replacement", there are many repair videos for the old Gameboys with exactly the same issue.
I have a similar display issue on my Logic Dart, although not as bad.
I removed the polarizing filter layer and put a new one on, but it didn't really help. Well in fact I cracked the top layer glass, so it made things slightly worse along the right edge.
As I had a dead HP48GX and a HP38G in pieces, so I tried an LCD swap but it didn't work. No display at all.
There is almost certainly a different connection layout due to the annunciators.
oohhh. i have one of those too. no i'm not selling it... they only made that for a short time. i got mine through a giveaway. buy 34401 multimeters and have a chance to win one...
Forgot to attach pics. These are before and after polarizing film change.
I was quite careful, but the damage I caused is pretty obvious. And the damaged area actually now has better contrast than the rest of the display.