Identifying a printer LCD panel - Page 1
Forum section: electronics / projects

author: MacAttak
author_rank: Unknown
timestamp: September 03, 2013, 01:24:57 am
content: I pulled this small panel (I think it is LCD) from one of those all-in-one Epson inkjet printers that wasn't worth repairing. It is roughly 1.6" x 2" (2.5" diagonal), color. It was pulled from an Epson Workforce 610.I've looked but cannot find out anything about this display. I'd like to figure out how to power it up and drive it - but not really sure where to start. So just looking for some starting pointers if anyone has any suggestions on where I might find a datasheet, or how I might go about hacking it and figuring it out that way. I've no idea what kind of interface these things usually have. From the close-up of the connector, it looks like power/gnd and six signal lines?Here are a handful of close-up photos. I tried to get clear shots of all identifying markings on the PCB (not sure if I actually need this to drive it?). I didn't turn up any real information by searching on all of the various numbers.

author: marshallh
author_rank: Unknown
timestamp: September 03, 2013, 02:56:50 am
content: My guess is it's a monochrome display with COG controller. LED boost converter is on the pcb. Check if there's anything on the back (probably not)Because there arent many data lines coming in, I'd say something similar to SPI, maybe quad SPI.As always the best way to reverse is while it's in the working system. Don't tell me you threw out the rest already

author: amyk
author_rank: Super Contributor
timestamp: September 03, 2013, 01:22:58 pm
content: There's probably something (controller?) on the other side of the PCB... since the FPC that goes into the panel itself has a lot more signals on it.

author: PA0PBZ
author_rank: Super Contributor
timestamp: September 03, 2013, 02:30:10 pm
content: Quote from: marshallh on September 03, 2013, 02:56:50 amI go for color, especially with CMKY printed on the pcb...

author: george graves
author_rank: Super Contributor
timestamp: September 03, 2013, 03:12:02 pm
content: Quote from: PA0PBZ on September 03, 2013, 02:30:10 pmCMYK usually refers to printing stuff - not display stuff.CMYK is cyan, magenta, yellow, and key. Key is a forth ink, cause the combo of the three can't make a true black (I think it ends up dark purple or soemthing) - "Key" is actually black ink. So, not part of an LCD display.

author: MacAttak
author_rank: Unknown
timestamp: September 03, 2013, 03:53:44 pm
content: It is color - I've seen it operating. You can see it in the product photo:http://www.epson.com/cgi-bin/Store/jsp/Product.do?BV_UseBVCookie=yes&sku=C11CA50201There are no components on the reverse of the PCB. Just traces.Yep, of course I've ditched the rest of it alreadyPretty much the entire machine had to be dismantled in order to get to the LCD panel - I don't see how I could have it powered up while being able to probe it without being exceptionally careful during disassembly to not damage anything else.My first thought is to give it power to the obvious +v/gnd pins, ramping up slowly from 1.5v or so until the backlight comes on and brightens to a normal level - which would at least tell me the expected operational voltage. But then I'm not sure where to go from there.

author: marshallh
author_rank: Unknown
timestamp: September 03, 2013, 04:50:10 pm
content: Pins 1-2 are Vcc, 11 is ground, 4/9 are probably ground as well but confirm.Try 2.5, then 3.3v. Failing that try 5vThe pcb layout smacks of Epson. What appear to be 6 data/control lines are carefully terminated with bypass caps.Maybe Vtt = Vcc/2?Having 6 data lines, I'd take a guess at:ClockStrobeData[3:0]To be honest you're best off tossing this, and buying a suitable replacement with a datasheet.Or, you could go google hunting for lcds of similar resolution and study with interfaces they use.Make sure there are no additional identifying labels under the PCB on the LCD lightbox plastic.

author: kfitch42
author_rank: Frequent Contributor
timestamp: September 03, 2013, 04:57:29 pm
content: 1) There is no chance in hades you will find information about the board. It is about 99.999% likely to be an epson proprietary thing.2) If you can remove the board and get details on the LCD panel itself, there MIGHT be information about that.3) Since you said there is nothing on the reverse of the board, I assume the large chip near the external connection is the LCD driver. Does it have markings? It might be some off-the-shelf micro... running epson proprietary code.4a) Your job, should you choose to accept it, is to learn how to talk to that chip.4b) Your alternative job, should you choose to accept it instead of 4a, is to learn to drive the LCD and LED backlights (I assume LED-A and LED-C) and skip out on the PCB entirely.My assessment is that you might get crazy lucky and talking to the chip is easy ... figuring out that it is easy probably requires a working example (to probe signals on) ... which you don't have.4b is possible, but given the time/effort involved you might be better off getting an off-the-shelf LCD module which has docs.Mike Harrison's series on REing the LCD module from an iPod might be interesting/tangentially relevant:https://www.youtube.com/playlist?list=PL0KZLmPyL6Ak1bArDuLo77yhx95yMsjHL

author: MacAttak
author_rank: Unknown
timestamp: September 06, 2013, 10:25:14 pm
content: I wasn't going to give up too quickly, but you guys are pretty much correct. I couldn't find a single datasheet or schematic for any of the chip numbers I was able to read (I went back and looked for any identifying marks I might have missed before, and also verified that the back of the PCD was unpopulated). So the chance of reverse engineering this one is very low - especially since I'm still lacking in experience and test gear at this point. My only form of signal generator would be custom code on an Arduino / AVR or something cooked up on a fpga dev board, and I don't have a proper LA, just a basic scope.About the best I could do at this point is probe around to determine the right vcc voltage(s?), but that would be about it without getting really lucky.I'll hold onto it though and give it another go later once I've picked up a little more experience. Yeah - it's not worth the effort when you can buy a raw screen of that size for $10 or one with a documented interface chip for maybe $20... I was just interested in it for the educational aspect.