LCD display having issues:
formatting link
Dead pixels, corroded/dirty ribbon cable contacts, or something else?
- posted
8 years ago
Dead pixels or...?
Loading thread data ...
- Vote on answer
- posted
8 years ago
Doesn't look like dead pixels, more likely a logic corruption. The wrong letter, maybe just a weak bit in whatever holds the program memory. Start looking at the power supply (hey, it's a WEAK bit, could just be low battery).
- Vote on answer
- posted
8 years ago
I agree. Check the power supply voltage.
My guess(tm) is that the display has a COB (chip on board) that has a broken wire bond and the display needs to be replaced. Just touching the blob of epoxy is sometimes enough to trash a wirebond and missing pixels cannot be produced by data errors between the synth and the display.
1601 displays are quite common and cheap, but not with EL backlighting. If you're going to replace it with an LED backlighting version, you'll need to:- Check the thickness of the display as they do vary and may not fit.
- Disarm, disconnected, and possibly remove the EL high voltage power supply.
- Find a way to power the backlighting. Some run on 5.0V, some bring out just the diodes and need a series resistor, and I ended up with one that wants 4.4VDC.
I thought it was easy, but it took me several evenings to replace the display:
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
- Vote on answer
- posted
8 years ago
Yes, that looks like a ribbon-zebra-LCD contact problem. Carefully dismantling the assembly, cleaning the LCD and ribbon contacts and then getting it back together is risky, but then it isn't working now, so not that much to lose.
Jon
- Vote on answer
- posted
8 years ago
Thanks for the reply. The original LCD was very old, and it literally crumbled in my hands as I attempted to disassemble it from the board to clean the contacts.
Fortunately, I managed to find a lot of 3 unlit LCD displays on eBay that look like drop in replacements for the original - they use the same SMT OEM Hitachi display controller in a similar package, and even the PCB layout is very similar. The date code on the original board looks like 1986, these are from the early 1990s.
$3 plus shipping for the lot. Seems like a much easier solution...:)
-- ----Android NewsGroup Reader---- http://usenet.sinaapp.com/