Replacing OLED screen on an Agilent U1253A Multimeter

[johns]

We have built a PCB using using your design based on satanistik design but still have the same problem with mirrored image
We must be doing something wrong but what we have no idea.
Do you have any suggestion what to check?

[coromonadalix]

see reply #196

[ultrasmurf]

How is the connection between the main pcb, small pcb (the one that suppose to invert the command), and the oled controller ?

[tautech]

Hello Johns,

Do you still have any replacement screens left?    pwrtrnx  -  NZ

regards

Welcome to the forum.

 
Kiwi with an Aussie flag ? 
FYI you can remedy this in your profile settings.

[Boosted_Eric]

We have built a PCB using using your design based on satanistik design but still have the same problem with mirrored image
We must be doing something wrong but what we have no idea.
Do you have any suggestion what to check?

I'm working on the same project for my power fc. Did you end up finding any type of solution? My screen is still mirrored as well.

[Zucca]

see reply #196

Which is --->THIS<--- one

PS: It is not hard to put a link for it...

[Murzzillkin]

Hello.
I have a U1273 device. The display does not work. Advise what to replace. Can not understand.

[rtekal]

Hi,

Heartfelt thanks to Satanistik, Ultrasmurf and Ginum for the design and PCB details.

I got both the PCB varieties manufactured locally. I used a MIDAS make 128 X64 OLED display MCOT128064EY-YM and assembled it using Ginum's PCB.

The display is working fine with the last column being displayed first. Also a line is displayed in the last row.The same is not seen in the displays of both Ultrasmurf and Ginum.

The second thing I noticed that is the battery seem to be draining a little faster than before. The unit is drawing about 45mA. While a non modified unit draws about 30 mA.

Thanks guys

Regards
Ramesh TN

[LagrangeWang]

thanks for your solution, but i want to know why there is column offset,is there any othoer improvement such as modify your schematic

[LagrangeWang]

hey ,my brother ,is there any difference with original solution(ssd1309 to ssd1303)

[LagrangeWang]

do you have a PCB file ,and i want to know why your solution doesn't have a coulum offset

[gmarsh]

I just pulled a U1253A out of the junk bin at work with a dead screen, that I'm gonna have a go at fixing.

I'm curious if I can fix the column offset issue, perhaps using a CPLD to offset the column address when it gets written in. If I'm lucky, the meter writes only full rows at a time starting at the same column address, and all I have to do is substitute the column address for another.

I'll be stuffing my MSO on the display header shortly to take some captures of the meter writing to the screen, and figure out how feasible this is. Updates to follow...

[gmarsh]

Update!

I hooked up the MSO to the meter and did some captures. Some observations:

- The meter doesn't seem to care that there's no LCD plugged in, and doesn't seem to ever read from the display.
- The meter doesn't write full pages at a time from the same starting column offset, it writes randomly to the screen.
- But... every time the meter writes to the display, it always writes the page first (0xB#), then the column LSB (0x0#), then the column MSB (1x#)

This means we can add a value to the column LSB command when it's written to the screen, catch the carry bit and add it when the column MSB command is written to the screen. This is an easy CPLD job.

I've attached some Verilog that implements this and also flips the bit to reverse the display. It's pretty simple and uses only 19/40 logic elements in a <$2 Intel 5M40E64 "MAX V" CPLD, which you can program with a ~$2 USB Bus Blaster clone. Right now I've got the column address offset set to +2 as a placeholder, which is probably wrong, but it's something I'll mess with once I get hardware in my hands.

Just ordered a OLED screen off aliexpress, and I'm gonna start throwing together a schematic.

I ordered a 31 pin solder-on screen that's the same style as the old screen, but I should measure and find out if a flat connector screen can be made to fit too.

[TestSubject]

I am excited to hear some updates gmarsh! For some reason, my U1273a got real dim with missing pixels after being shipped across the pacific...

Which display did you end up buying? If you need help with PCB design and/or testing, I am happy to oblige!

[gmarsh]

I am excited to hear some updates gmarsh! For some reason, my U1273a got real dim with missing pixels after being shipped across the pacific...

Which display did you end up buying? If you need help with PCB design and/or testing, I am happy to oblige!

Time for another update I guess:

- I sniffed the screen activity some more, to get a full idea of what the meter writes to the display.
- The lowest column address value sent to the screen is 0x02, which causes the column shift everyone is seeing. So all we need to do is subtract 2 when an address is written to the screen and that should center everything properly, and since the address is sent LSB-first from meter to screen (on the 1253A, at least) we can do that.
- The Verilog I posted earlier will wreck some command arguments that are sent to the screen on startup, so don't use it I've got newer CPLD code now which looks for commands that take an argument and passes through the argument unmodified, and still fits in a 5M40ZE64 CPLD with ~60% utilization. I'll probably throw down a 5M80 for the first prototype run in case I run into any surprises.
- And I've got a new PCB designed, which I'll be ordering in the next week or so.

I'm also laying out a tester PCB that a display plugs into so I can measure all the rail voltages, program the CPLD and show a test screen on the OLED without having to use a real (and expensive) meter as a host. I'm also finishing a couple other projects to make one big JLCPCB order (+ one big Digikey order) at once.

I ended up ordering this screen afterwards:
https://www.aliexpress.com/item/4000321242073.html

I don't need any help with the PCB design, but my big question is whether what I'm doing here for the U1253A can drop into your U1273A. Any chance you've got a 4 channel scope or MSO or anything that can capture what gets written from the meter to the display?

[eb4eqa]

Hi gmarsh. Very interesting, thank you! I have one U1273A and MSO. I will look at it over the weekend ok?

Roberto

[johns]

We had to redesign the conversion PCB and use different parts as well and now it is working fine.

[johns]

How is the connection between the main pcb, small pcb (the one that suppose to invert the command), and the oled controller ?

We had to redesign the PCB/schematic and use different parts, it is working now fine.

[johns]

We have built a PCB using using your design based on satanistik design but still have the same problem with mirrored image
We must be doing something wrong but what we have no idea.
Do you have any suggestion what to check?

I'm working on the same project for my power fc. Did you end up finding any type of solution? My screen is still mirrored as well.

Yes, we did it. See our latest post.

[johns]

Thanks Johns, I'm interested because, off course, I have a U1253 multimeter with dim to death screen, but looking at pictures the conector it's different that multimeter connector. Are you sure that this boards work?

IMHO it's a spam from some Chinese folks. And this display has nothing to do with U1253A, connector looks similar to generic OLED display boards.

No, it is not a spam from China, I am in Perth, WA and we find the solution to fix the Ap5exi commander OLED screen replacement to work.
And further more we have some extra boards with parts as per ultrasmurf design for Agilent U1253A DMM

[johns]

Hello Johns,

Do you still have any replacement screens left?    pwrtrnx  -  NZ

Yes, I have some extra boards as per ultrasmurf solution for Agilent U1253A and with all the parts on the board.
For our project we had to redesign all and it is working fine.
For Agilent the board is ready to use as per ultrasmurf design.


 

[gmarsh]

Hi gmarsh. Very interesting, thank you! I have one U1273A and MSO. I will look at it over the weekend ok?

Roberto

Thanks for offering!

The pinout for the U1253A screen is on mcookieman's post here:
https://www.eevblog.com/forum/testgear/replacing-oled-screen-on-an-agilent-u1253a-multimeter/msg2428572/#msg2428572

There's a female connector on the main PCB, you'll want to find a matching 2mm pitch connector that plugs into it to give you something to clip your DSO leads onto. If your display's dead I suppose you could just rip the connector off it and use that. Just please don't poke old resistor legs into the connector and damage your meter to do this test for me.

I hook up R/W, D/C, the 8 data lines and ground. Set up the MSO to trigger on D/C being low and a rising edge on R/W.

There's a blast of assorted commands when the meter starts up, after that the U1253A spits out over and over again:
... bunch of data writes ... <Bx> <0x> <1x> ... bunch more data writes ...
Bx selects the page, 0x is the column address LSB, 1x is the column address MSB. Key being the LSB comes first.

I should have taken an actual screen capture from the MSO instead of a picture of what I was doing, but you can see the address write waveform in the picture I posted earlier. I'm hoping the 1273 does the same.

[Bhflex57]

Hi. Can you please send me any website where I can get the OLED module for my Agilent U1273bAX  ? I see a few links that don't work but don't know where to get the part .
SOS electric needs a part number .
Taobao link doesn't work .
I appreciate the help !

[Bhflex57]

Hi.
Do you now have a fix for the OLED screen replacement on an Agilent U1273 AX DMM ?
If you can help with part numbers , place to order , other necessary steps , etc. I would appreciate it.
Do I need a new board as well ? Your custom one ?
Please let me know.
I am in US .
No repair shop seems interested or able to find the part .

[gmarsh]

Another update:

JLCPCB and Mouser orders placed! I've ordered 5 PCBs, 5 PCBs worth of parts, but still have just 1 screen coming from Aliexpress.

Thanks to EB4EQA's work, I can confirm the U1253A/U1273A both write to the screen identically, and this solution should work in either meter.

Next update will come in a couple weeks when I have all hardware in my hands.