EEVblog 1564 - Agilent/Keysight U1273AX Multimeter Repair

A very interesting repair of an Agilent/Keysight U1273AX OLED display multimeter. It had two distinct unrelated faults.

00:00 - Faulty Agilent / Keysight U1273AX OLED display multimeter
01:36 - Battery leakage, OF COURSE!
04:26 - Bottom of PCB
05:47 - The OLED display
10:09 - Annoying voltage measurements
15:14 - At great expense to management, a new OLED
18:18 - Winner Winner Premature Dinner
20:19 - The Repair is over, right? RIGHT?
21:22 - Accuracy fault. Repair time again.
25:23 - Hybrid Thin Film Resistor Dividers
26:56 - Parallel contamination
29:44 - When in doubt, suck it off

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#ElectronicsCreators #Repair #Multimeter

[flomojou]

OLED displays are extremely sensitive to oxygen and moisture ingress, which is one of the reasons they are expensive-- they must use a glass envelope with metal feedthroughs that is hermetically sealed. Can't recall the channel, but the owner actually did some of the R&D on the original displays, and he explained how that was a major hurdle when developing them, just how to create a perfect seal. Apparently it wasn't that difficult to get them emitting light, but without that seal they will very quickly fail.

[mikemike]

Your recent repair videos demonstrate a remarkable ability for planning years ahead, leaving batteries in so many devices and waiting for them to leak. Of course, I find these videos quite entertaining, although my first thought is oh, Dave, not again.

[flymypg]

It's situations like this that have me fondly remembering our old-school ozone-killing Freon dip baths for PCB cleaning and decontamination.

[NoLandMandi]

It was really cool how you found the calibration fault by reasoning and analyzing the way the front end would work!💪

[mysockC]

I have this series of Agilent DVM, and leaking batteries absolutely wreak havoc on the plastic. I had to make do with popsicle sticks and epoxy as the “new” battery compartment since the old one turned to dust.

[georgegherghinescu]

High impedance board cleaning would make a great topic for a video. Almost nothing about it on youtube. The proof of a clean board is a test at 90-95% humidity, cleanish boards can pass at low humidity like in an airconditioned room.

[mrpetit]

Fail for Agilent.
Not only having their top tier multimeters failing their displays, but also not having spare screens available, luckily the aftermarket came to the rescue, this time.

[AlexTaradov]

Back to front is a very common issue. In the display controller it is done with a single bit, and if you are trying to send commands before display is ready, it may be missing that command. And those displays take forever to initialize.

[dangillham]

My OLED went on my U1273AX - just completely blank one day. I ordered an LC-OL12864-09-YO-A7 from LC Design (Germany, around 110 euro incl shipping) and it dropped straight in & works perfectly. Such a shame Agilent presumably know full well this is a design issue on a very pricey meter (as they offered replacement screen modules) - Didyou see their pricing for a replacement (when they offered it)? Truly stupid expensive. It's my most expensive meter, and the one that lasted the least long. Now happily working again without fault. Nice video, Dave, as always.

[kuenrg]

Dave!!! I have a similar model Keysite that had leaking batteries and has never been the same since. I cleaned it but now will give it another shot based on your repair! So glad i watched to the end. Thanks for such high quality videos!

[MaxPivovarov]

To wash the pollution, it is not enough just spray and wipe with a brush, you need to collect the dissolved pollution using a napkin. If an alkali hit the printed circuit board, you must first wash it with a light solution of citric acid, then rinse with water with a soap, and then rinse with ethyl or isopropyl alcohol and wipe dry with a napkin. I saved a lot of electronics flooded with different active liquids (alkalis, acids, salt).

[bluetrepidation]

I recall sending my meter in for a recall. Keysight exchanged it for another model. I can't remember what the issue was with the original product though. Stinks because the OLED is great for use in pitch black electrical cabinets. Easy to read at any angle.

[ovalwingnut]

By chance I ran into someone I didn't know and we both agreed that this was 1st class infotainment. Just saying. Cheers!

[jonfreeman]

Amazing repair. Great diagnostic and reasoning to isolate the problem and $80 for a screen is still worth it for this high end meter. The screen is beautiful.

[ahc]

You'll find that your calibration problem is probably due to battery electrolyte soaked into the fibreglass of the pcb causing stray conduction paths. I have come across this problem before. It's a very difficult job trying to remove the paths by soaking it in solvents etc for many days, but always worth a try I suppose.

[Graeme_Lastname]

I bought my el-cheapo DMM about 20 years ago, and it still works. 🙂

[DrFrank-xjbc]

. Great repair video. Finally. Thank you, Dave

[ScoochieR]

I would use the choice of OLED over LCD in an otherwise equivalent Keysight DMM as a really good tell in a job interview.

[kalhana_photography]

This is my favourite multimeter. The OLED screen is great to read at any angle. Also I use the non-OLED version of this which I don't like as much. Also I find that the Fluke 289 is the worst LCD I've ever used (can't read it unless looking at it directly).
On the U1273AX, I've disabled that silly startup melody and also disabled auto power off (nothing worse than using all hands and legs to probe something with the tongue at the right angle and the DMM beeps and goes off!).

[erichschlecht]

My lab received 5 of these as "freebies" when we bought real Agilent Source Measurement Units (~$10K each). Five years later NONE of them worked. No battery leakage. We threw them out. My Fluke 23 I bought new in 1981 works like the day I bought it. All the handhelds we use now in the lab are brand 'F'.