Unobtainium Philips PM2525, PM2534, and PM2535 LCD replacement

[TIG]

I have a Philips PM2535 System Multimeter with a leaking and defective LCD.

Luckily, EEVblog contributors Cowasaki and Hackwell  found a way to drive a suitable OLED display by tapping of the I2C signals to the LCD driver using an Arduino Nano. See their post in the links.

I have improved the C++ code for the Arduino Nano. Improved the layout of the elements on the display such that we utilize the full potential of our 256x64 display. And added STL files, for 3D printing a frame and mount for the OLED display and the Arduino.

The result and some intermediate steps are shown the attachments. The software, the designs for the frame and mount, instructions, information about the infamous probe plug, and all other materials are published on GitHub.



I owe many thanks to EEVblog contributors Cowasaki and Hackwell for their work.

[delvo]

Really cool. I have a PM2525. The screen isnt broken but without any backlight I am basically never using it. I might do this as a mod

[abeyer]

Agreed, I'd seen the prior work on this, and thought about doing it just as an upgrade, but all the fit and finish that was lacking made it more of a project than I was ready to take on. Thanks for getting this put together!

[delvo]

I was about to put in a jlcpcb order in today anyway so I quickly designed a board for it. Im using a stm32 so it will require some software modifications. I got it down to ~17€ for 5 boards (minus the headers. Im not paying 3x3€ for them to solder them). Still blows my mind how its possible to do that this cheaply.

[TIG]

Really cool. I have a PM2525. The screen isnt broken but without any backlight I am basically never using it. I might do this as a mod

I didn't think about this, LCDs aren't the most legible displays indeed. In contrast, my PM2535 with a green OLED display is the most legible meter in my lab now.

Just replacing the LCD as a mod makes sense.

[TIG]

I was about to put in a jlcpcb order in today anyway so I quickly designed a board for it. Im using a stm32 so it will require some software modifications. I got it down to ~17€ for 5 boards (minus the headers. Im not paying 3x3€ for them to solder them). Still blows my mind how its possible to do that this cheaply.

Please share some photos when your mod is finished.

[delvo]

Will do! But there is a >0% chance it wont work or wont fit. I put that together very fast and did no measuring to see if it will fit. I also still need to order a screen which is surprisingly more expensive than 5 of the mod boards.

[TIG]

About € 20.- including shipping: https://www.aliexpress.com/w/wholesale-3.12--OLED-display.html. That is about 1m€ (€ 0.001) per pixel  .