Replacement LCD for Keisoku Giken ELS-304 - Page 1
Forum section: electronics / repair

author: little.tesla
author_rank: Regular Contributor
timestamp: July 18, 2025, 07:58:19 pm
content: Hi all,I’m looking for some help with a Keisoku Giken ELS-304 that has a broken LCD display (flat flex ripped off from display).The original display has the following characteristics:Flat flex: 33-pin, 0.5 mm pitchSupply voltage: 5VResolution (assumed): 128x64 pixelsI’ve already searched (eBay, AliExpress and similar usual suspects) but haven’t found a direct replacement. Most displays I’ve found differ either in pin count, supply voltage (commonly 3.3V), or overall interface compatibility.I’ve attached pictures of the display, including one showing the pinout I’ve reverse-engineered.If anyone has experience with this unit or knows of a compatible replacement or even a sensible substitution path (e.g., alternative module with adapter), I’d really appreciate your advice.Thanks in advance!

author: Poroit
author_rank: Frequent Contributor
timestamp: July 19, 2025, 06:38:01 am
content: G'day little.tesla,Can you source a display from the manufacturer?PWsales@hq.keisoku.co.jp

author: little.tesla
author_rank: Regular Contributor
timestamp: July 19, 2025, 07:22:26 am
content: Thanks for the hint!I wrote to them already a few weeks ago, but no response so far. I'll try to send them another email.Kind regards

author: u666sa
author_rank: Frequent Contributor
timestamp: July 19, 2025, 09:24:46 am
content: You'll have to resoldering that LCD cable, or hire someone to resolder it for you. Based on pictures it looks like an easy $180 job.

author: u666sa
author_rank: Frequent Contributor
timestamp: July 19, 2025, 09:25:41 am
content: You'd have to send in your device with LCD for testing, but otherwise it's straight forward. As far as locating this same exact LCD screen, forget it. Your only other option is finding a donor.

author: little.tesla
author_rank: Regular Contributor
timestamp: July 19, 2025, 11:55:46 am
content: Thanks for the feedback, much appreciated!I should clarify a few points:- This exact unit and similar ones seem to be extremely rare on the western market, so finding a donor device is unfortunately unlikely.- Regarding the broken display: it’s not just a damaged panel. The main issue is that the flat flex cable has detached from the display itself, and the flex is super fragile — it breaks if you even slightly bend it. If the problem was only the flex cable, I could have fixed it myself.- I already tried hooking up a similar display (NHD-C12864WC-FSW-FBW-3V3) using a 5V to 3.3V level shifter (74LVC245) respecting both way communication. Unfortunately, no luck. From sniffing the communication I noticed that the unit appears to read back data from the display during boot, and it hangs at startup (the two characteristic beeps are missing).Unfortunately, I don’t have access to any company locally that could reattach the flex properly. That requires specialized equipment and skill.If anyone has tips on finding a compatible replacement or knows more about how this particular display might operate (especially around read-back behavior), I’d love to hear suggestions!Thanks again for all the input so far.

author: little.tesla
author_rank: Regular Contributor
timestamp: July 19, 2025, 03:20:33 pm
content: Quick update for everyone:I’ve spent a bit more time debugging my display replacement setup. After fixing some crude wiring to the level shifter and finally connecting the jumper wires to the correct pin numbers (counting is apparently difficult after a long day 😅)… Success - it works! 🎉Now I’m thinking about designing a proper adapter PCB to clean it all up.For anyone who might want to replicate this:- I used 2x 74LVC245 for level shifting.- For the data lines, I added a NOR gate for direction switching, using CS and RD as inputs to the gate.- All control lines only go one direction, therefore hard wired.Thanks again for all the input and encouragement - really appreciated!

author: coromonadalix
author_rank: Super Contributor
timestamp: July 20, 2025, 12:38:46 pm
content: hi great work, you should provide a schematic or crude hand mmade on to help others who may face the same problems

author: little.tesla
author_rank: Regular Contributor
timestamp: August 19, 2025, 08:12:23 pm
content: Full KiCAD project for easier replication can be found here:https://github.com/little-tesla/KG-Display-Adapter