Products > Test Equipment
Replacing OLED screen on an Agilent U1253A Multimeter
zoiasso:
--- Quote from: ultrasmurf on June 01, 2020, 12:26:36 pm ---Built PCB using satanistik design with abit change here and there. Using 1309 display, there is column offset. I have bunch of spare pcb if anyone need it, just throw some beer my way. Gerber file attached, so anyone can just send to manufacturer like seeedstudio or other cheap pcb builder. It's panelized so go grab your friend to share the mfg cost. You can attach the PCB directly to 1253B pcb.
U1 is 4071, im using Nexperia HEF4071BT, mouser pn 771-HEF4071BTD-T
U2 is 4078, im using TO CD4078BM, mouser pn 595-CD4078BM
U3 is 74AHC1G00W5-7, im using Diodes inc, mouser pn 621-74AHC1G00W5-7
Decoupling/bypass capacitor use 0805 smd cap. I'm using 100nF 16v just because it wander near my soldering station....
Aligning the PCB to go to the display daughterboard is trivial, I forgot to print alignment mark on the PCB, just scrape off a bit on the edge of the PCB to mark the edge location of pad 1 and pad 31, align it on the daughterboard and solder it like you would soldering any smd component.
File for the PCB is uploaded to Seeedstudio fusion galery as well, not making any money out of this link, it just make it easier for any of you that need the PCB in the future.
--- End quote ---
does this work with ssd1305z or ssd1306 ?
onesystem:
This is in regards to U1273AX.
Obviously same screen problem.
On Keysight website there are two branches of firmware. Latest versions is 3.03 and 4.02
I compared the two differences, and major difference is in a file called "u1273ax_v303.ag" vs "u1273ax_v402.ag"
I am not a programmer so I do not know the .ag file extension. Surface search states that .ag file is a "applix graphic" file extension, which may or may not be this particular file. If anyone knows, please fill in the missing info.
Here is why I am posting this here. Since it is a definite that SSD1303 has been discontinued, it follows that current replacements by Keysight would be SSD1306 or SSD1309, which means automatically that firmware would be adjusted. So I figure that is why there are two branches of firmware - due to display differences... Let me know if my reasoning makes sense.
Maybe one of you does have firmware version 4.02 on your meter and can confirm if your OLED has a different driver chip on it - SSD1306 or SSD1309. Keysight used SOLOMON Systech company for their 1303 OLEDs.
Maybe problem these days is quite simple - buy the same screen that Keysight currently swapping their meters with, update with 4.02 firmware and there you go. I just got quoted for 402USD to swap my dim screen to a new one...
Can anyone confirm or deny my reasoning? I find it quite improbable that Keysight is still swapping their screens with SSD1303 drivers due to it's discontinued state.
onesystem:
Here are both versions of U1273AX firmware for investigation:
V3:
https://drive.proton.me/urls/N55QYAYX80#j24y3g6IIvZT
V4:
https://drive.proton.me/urls/5J0FE0ZPMC#invyx6Y26hik
onesystem:
Me again.
Main chip on meter is RENESAS D78F0547.
Here are links to programming manual:
https://drive.proton.me/urls/G0F5REFDBC#tp38ti26zHNf
and the datasheet:
https://drive.proton.me/urls/SF51ZB1RF4#R0M7AdtgC0SV
Is there a way to decompile the firmware update using the programming manual data? Or is it a 100% lost cause?
onesystem:
Agilent U1273AX / Keysight U1273AX
Original Screen is SSD1303 driver, SOLOMON SYSTECH
Digital Multimeter microprocessor is D78F0547, datasheet and programming docs are in earlier post.
Keysight has firmware updates, links to them added in earlier post.
I erroneously thought firmware version 3 and version 4 are due to different screens. That was an unreasonable assumption. I do not know the difference but I can't verify if it is due to a different screen SSD version. In fact I have not seen on the net anyone claiming that their meter is with anything newer then 1303 from the factory.
My focus on now is how to disassemble the firmware, amend it's code to match a newer OLED driver, compile it back and push it over to the multimeter.
Searching the net I found a guy who wrote a disassembler for this type of chip. Here is the GitHub page:
https://github.com/mnaberez/k0dasm
His code is specific to a different chip though, so I had to update two of his files, command.py and symbols.py, with hardware vectors and special function registers for D78F0547.
Here are the links to these two updated files:
command.py - https://drive.proton.me/urls/SERRTAHHZM#XDrd7wwvzOkc
symbols.py - https://drive.proton.me/urls/NXZ45SNNMW#aJBO1dpW3PZv
Inside firmware you will find 18 files called Binary.NewBinary1 through Binary.NewBinary18. Those are the firmware for our chip (at least this is what I can see so far, please correct me if I am wrong).
Running each of these files through k0dasm, we get output which is to be processed through ASxxxx 5.50 Cross Assembler (https://shop-pdp.net/ashtml/asxget.php). Obviously before that it would have to be inspected and edited to amend the communication with OLED screen driver.
In terms of loading our edited firmware onto multimeter, Keysight allows to roll back the update to a previous version which in turn will allow to update it back to current version. Just swapping the Binary.NewBinary1 through Binary.NewBinary18 inside the update file with our amended ones then will allow to upload the firmware onto multimeter.
Where I have a steep learning curve ahead is to understand the output code from k0dasm. It is assembly and I do not know it. Maybe someone here can help, or maybe all of this is somehow a dead ending without me realizing it - let me know!
I hope to learn a lot as a result of this project. And obviously simplify replacement of the OLED screen.
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