Dim OLED Screen replacement for Agilent Keysight U1253A U1253B U1273A U1273AX

[onesystem]

So now resetting the ports before jumping:

Code: [Select]

sub_7f00:                                           ; From bootloader
    br !llab_7fdb            ;7f00  9b db 7f         ; Go to failsafe check

lab_7fdb:                                           ; Failsafe check
    mov pm7,#0xf0           ;7fdb  13 27 f0         ; Set P7.7-4 as input, P7.3-0 as output
    mov pu7,#0xf0           ;7fde  13 37 f0         ; Enable P7.7-4 pullups
    mov p7,#0x00            ;7fe1  11 07 00         ; P7.3-0 outputs low
    movw ax,#0x0100         ;7fe4  10 00 01         ; Much smaller delay

lab_7fe7:
    subw ax,#0x0001         ;7fe7  da 01 00
    bnz lab_7fe7            ;7fea  bd fb   
    mov a,p7                ;7fec  f0 07            ; Move  P7 value into A
    mov pm7,#0xff           ;7fee  13 27 ff         ; Clear port config
    mov pu7,#0x00           ;7ff1  13 37 00
    bt a.7,lab_7ff8         ;7ff4  31 7e 01         ; test A, bit 7
    ret                     ;7ff7  af               ; Return (Button pressed)

lab_7ff8:
    br !lab_3015            ;7ff8  9b 15 30         ; Enter app (Not pressed)


Finally loaded the "U1273AX_V301_failsafe_p74.ag" on meter. Meter works fine, no problems at all.

I used DSD Tech SH-U06A to load it this time so I don't have to take apart optical comm and solder in the Rx Tx Gnd pins. See attached photos.

Now, what is the expected operation of this failsafe version?

[DavidAlfa]

It's just reading a different input. Try finding which button causes it to go into update mode (Holding while powering on).
Might not be connected to any button, that's why I made the four p77...p74 tests.

[msquared]

Wanted to give a BIG THANK YOU! to both you guys. 

I replaced the display on my U1253A and upgraded the firmware today.

Attached pictures tell the story.

I also posted this success story in the testgear thread.
https://www.eevblog.com/forum/testgear/replacing-oled-screen-on-an-agilent-u1253a-multimeter/msg5311756/#msg5311756

[bson]

Forked k0dasm with the command.py and symbols.py changes to support the D78F0547 at https://github.com/bson/k0dasm

[Njk]

So there is NEC uPD78F0547 inside. My Fluke 189 uses Sharp SM6004 chip. No docs, no tools, etc. What was the reason for widely using a Japanese MCUs in the DMMs of the US brands? If there was a shortage of the domestic MCU designs back at that time?

[bson]

IMHO relying in the forum storage is the least reliable way, but attached anyways  .

Just for reference, I also forked it at https://github.com/bson/78k0-flash-utility

[voltsandjolts]

So there is NEC uPD78F0547 inside. My Fluke 189 uses Sharp SM6004 chip. No docs, no tools, etc. What was the reason for widely using a Japanese MCUs in the DMMs of the US brands? If there was a shortage of the domestic MCU designs back at that time?

Maybe those design teams are in Asia, and they naturally gravitate to home-grown mcu's.
US based design teams are perhaps more focussed on bench / high-end gear, where "western" mcu's are common.
Just guessing. Maybe just cost driven.

[gamalot]

So there is NEC uPD78F0547 inside. My Fluke 189 uses Sharp SM6004 chip. No docs, no tools, etc. What was the reason for widely using a Japanese MCUs in the DMMs of the US brands? If there was a shortage of the domestic MCU designs back at that time?

Maybe those design teams are in Asia, and they naturally gravitate to home-grown mcu's.
US based design teams are perhaps more focussed on bench / high-end gear, where "western" mcu's are common.
Just guessing. Maybe just cost driven.

I don't know about Fluke. Keysight's handheld multimeters are designed and produced by Escort Instruments, a Taiwanese company acquired by Agilent in 2008.

[xinchengGE]

How to replace the Agilent / Keysight OLED display for just $10!

- Buy the display: Aliexpress (Or search for "SSD1309 8080").

    (Attachment Link)

- You might need to install the Prolific drivers. If getting code 10, install the attached drivers.
- Make sure Windows is using them: Open the Device Manager, check those under USB devices/USB serial port and COM ports/USB serial port, replace driver if needed.
- Don't attempt loading a firmware from another model, it'll brick the device! (Not irreversible, see Recovering section below)


Agilent / Keysight U1273A / U1273AX

  If your device has firmware version v4.xx it will work straight away, no firmware modification is required!

 - Confirmed working!
 - Download and extract U1273A(X)_V303_mod.zip.
 - Run the updater.

 - Original installers from Keysight: U1273A, U1273AX .
   Must be v3.01, newer version will check the current firmware and block the update if already in the latest version!
   Just change the firmware name to U1273A(X)_V301.AG. (A or AX).


Agilent / Keysight U1253A

  - Confirmed working!
  - Download and unpack Agilent U1253A Firmware Update V120_mod.zip.
  - Run the updater.


Agilent / Keysight U1253B

 - Same mod as 1253A, so it should work.
 - Download and extract U1253B_V304_1123a_mod.zip.
 - Run the updater.


Reverse enginnering details

All the bits & low-level details can be found few posts below.


Recovery

If something goes wrong, it's pretty easy to recover using a usb-serial converter, read the messages starting here.

Great thanks to you guys working on thist project！my meter is now back to live again.
But as a reminder, I think you guys should uploader your work on github or a similar platform and attach a License to it.
I am from China and have already seen someone selling this firmware on the local network.