Salvaged LCD Display - Page 1
Forum section: electronics / beginners

author: Dumpsterholic
author_rank: Regular Contributor
timestamp: February 24, 2018, 03:57:10 pm
content: Hello.I have a nice-looking 3-inch LCD display that came from a junked Rocketfish UPC. The display sits on its own circuit board which includes two switches, a half-dozen SMT resistors, capacitors and diodes, plus an unknown controller chip buried under black goo (epoxy?).There is a cable coming out of an attached connector which has eleven wires. Since I paid nothing for this display, I'm not too concerned with burning it up. What I'm wondering is if there is some kind of standard wiring for these 11-wire LCD's so that I can go about testing it. My guess is that the thing works just fine, and that all I need to is power it up. Any ideas? Thanks.

author: Buriedcode
author_rank: Super Contributor
timestamp: February 24, 2018, 04:12:21 pm
content: Without a part no. number or even a photo, I'm not sure you'll get many replies. There are plenty of standards, for character and 128x64 displays - although the pinouts for the latter tend to be vendor specific - but there are also many custom displays specific for products. I'm sure these can be reverse engineered - using a logic analyzer and the original equipment it was in toe "sniff" the control/data lines - its a hell of a lot of work.So, maybe a photo/part number would help!

author: Dumpsterholic
author_rank: Regular Contributor
timestamp: February 24, 2018, 07:10:51 pm
content: Buriedcode:Tried to upload some pics, but failed because the files were too large. Here's another stab at it. I previously Googled all the part numbers and browsed for similar displays with specs, but came up short. No worries; the Dumpster giveth, the Dumpster taketh away...Given the low costs of Chinese-sourced displays, this may be a futile effort. Thanks for your time.

author: Buriedcode
author_rank: Super Contributor
timestamp: February 24, 2018, 07:22:16 pm
content: I'm going with custom display, as I have no idea if its graphic, character, digit, TN, STN FSTN etc..Given that there is more than jsut an LCD on that board, one can assume that some of the 11-wires are for non-LCD things, like switches, LED's etc.. So I'm going with a serially controlled display. Once you've identified the power lines, the ones for that switch, and the power for the LCD backlight, youcould probe the rest with a logic analyzer to see whats happening, if there really is a clock and data line.I suspect it is a lot of work for little gain - but I have done this sort of things before, purely because I dont' like throwing things out and some displays are really rather nice. Depends on what equipment you have to hand (a $10 logic analyzer will do just fine for this sort of thing, although it might not have protocol decoding, which isn't always needed) and how much you wish to re-use it.If you're just starting out it might be a lot of effort, but you could always just stash it in your parts bin should you wish to come back to it at a later date. Be warned, that sort of habit can be dangerous... I have over 35 displays waiting for projects to use themDo you have a link to the product it came from? I googled but found nothing with a display.

author: bitseeker
author_rank: Super Contributor
timestamp: February 24, 2018, 11:41:48 pm
content: Quote from: Dumpsterholic on February 24, 2018, 07:10:51 pmTry saving the images in JPEG format instead of GIF. If you can adjust the quality of the JPEG compression, a setting around 85-90% should work fine.

author: Dumpsterholic
author_rank: Regular Contributor
timestamp: February 24, 2018, 11:49:05 pm
content: Rocketfish no longer makes or services the 850VA uninterruptible power supply I pulled this display out of (follow the link below to see a pic of a comparable unit on the top left). I could not find a service manual either.I've never used a logic analyzer, but since as you say a $10 unit might help with probing this particular display, it could certainly be useful for many other tasks. Just yesterday I received my very first oscilloscope (the highly-touted Rigol DS1054Z) which I don't know how to operate; but as I regularly set money aside from my job, I intend to keep buying more test equipment, so another ten bucks is no sweat. Can you give some pointers on what to look for when testing a an unknown LCD?Another LCD will come my way soon, of that I'm sure. My Dumpster-diving skills are finely honed. I know what to look for and where, always carry a tool kit for quick disassembly, and have learned to recognize any number of devices from which valuable parts can be salvaged on the fly, leaving the detritus where I find it.Here's the link, and thank you for your interest:https://www.amazon.com/APC-Back-UPS-Protector-Charging-BE850M2/dp/B01HDC21FE