With joint efforts from fellow eevblog members, there is a relatively simple solution for screen replacement with 100% functionality for U1273AX:
1. Buy an OLED screen with 31 pins (make sure it is 31 pins), and driver SSD1309
I bought it on eBay here in the USA (
https://www.ebay.com/itm/364637366020), but also they are available on AliExpress (
https://www.aliexpress.us/item/3256805110683974.html)
INSTALLATION:
2. Remove the dead OLED screen from PCB. I used long blade to cut through the foam with extra care not to scratch the circuit board, then scraped off leftover foam with plastic tools. Applied double stick foam in layers until matched thickness of the foam that I destroyed which is 2.5 mm as far as I remember
3. Desolder the dead OLED contact pads from PCB, clean them up, apply thin layer of solder to them and prime it with non corrosive flux.
3. Color the foam edges with black marker if you see foam behind new OLED screen (do this before applying the screen to sticky foam pad)
4. Align the OLED screen to PCB according to little white markers oulining the corners of the screen edges, press it against foam pad you built and colored.
5. Solder the contact pads of OLED screen to PCB
6. Assemble the meter
FIRMWARE:
7. Download firmware update 3.01 from
www.keysight.com:
https://www.keysight.com/us/en/assets/ndx/9018-33296/miscellaneous/U1273AX-Firmware-Update-Software-Version-3-01.zipand install it.
8. Take this patched firmware 3.03 that will work with SSD1309 OLED screen:
https://drive.proton.me/urls/3RS0DT5M4C#BfzycVVQZKQyHere is a full thread on research and development of the said patch:
https://www.eevblog.com/forum/microcontrollers/8-bit-78k0-d78f0547-help-with-firmware-modification/There you will see the patch details. DavidAlfa (
https://www.eevblog.com/forum/profile/?u=555408) was most instrumental in helping me all the way on this.
9. Rename the downloaded firmware to "u1273ax_v301.ag" and replace existing file with same name in the directory of firmware updater:
[C:\Program Files (x86)\Keysight Technologies\Keysight U1273AX Firmware Update Software (Version 3.01)]
10. Connect U1273AX to the PC with installed firmware updater using cable U1173
(since mine was the obsolete U1173A, I had to replace the chip on it so it works with Windows 11)
https://www.eevblog.com/forum/repair/u1173-connectivity-cable/You should have no problems using U1173B
11. Turn on the meter and start the updater, load the firmware and enjoy the bright OLED screen on your meter!