Keysight - Agilent U1232A Multimeter Repair

[MrAvlis]

Hi EEVBloggers

Just like in video 1497, my Agilent-Keysight U1232A multimeter got damaged by leaking Duracell batteries

The multimeter was left unused for... 2-3 months perhaps. Not longer than that. But that's life.

I started seeing odd readings, and now it simply powers on showing nothing on the display and stays with flashlight on.

I'm determined to fix it since it is a really nice multimeter that has been with me for several years already. The problem is: I can't find schematics for it anywhere, so it impossible for me to determine the exact specs for the parts I need to replace.

Perhaps the community has some more detailed info on this multimeter, or can use an working multimeter to help me figuring out the parts...

Fortunately the soldering mask wasn't affected like the Fluke and the traces are intact.

I'm attaching some pictures for your reference. What I need is the values for:

• C50
• C52
• C59
• C60
• C61
• C62
• C68
• C69
• CR18
• CR22

I know that this is a difficult ask, but any help is greatly appreciated, as well as repair hints and other pertinent suggestions

Thanks a lot!

[nightfire]

I just bought an also defective (battery spill...) U1232A, that should arrive at the weekend.
I will report what I can see, and with a bit of luck we have different broken parts. Seller mentioned 3 SMD pieces dissolved by battery juice, so I am curious what the h*** happened.

Which PCB revision do you have?

[2N2222A]

Typically it's the copper board traces that are connected to positive Voltage that are damaged. The components themselves are okay. The traces are damaged under the green solder mask, so it doesn't look so bad at the surface. The damage occurs when the new battery is put in while leaked electrolyte from the old battery is still in there.

It's the positive traces that need to be checked.

[nightfire]

I received my broken U1232A yesterday. From what I could see:
On the PCB it reads: U1233-26500, REV006, and a yellow sticker with "MSS-B" on it- last part on the number obstructed by the fuse holder directly placed above it

I measured the available to me pieces in-circuit,  so that we have some rough idea with what we are dealing.

C50: Same as C99, labelled as: 245/100/16E
C52: broken myself
C59: 26µF
C60: 27µF
C61: 9µF
C62: 176nF
C68: 25µF
C69: 16µF
CR18: broken myself
CR22: labelled like: P.D and a horizontal 6 or 9, depending on your orientation on the board, measures as a diode 0,6 and 3V in both directions, although I would need some more information on this part  to measure it correctly.


I would need myself the values of:
C52
C206
C207
CR18
R06

[MrAvlis]

Hi guys, sorry it took some time to reply back.

Thanks 2N2222A - Indeed we need to look carefully at the positive traces. I did some testing with another multimeter and they seem ok, but I'll re-check with a small microscope that I have.

I'll summarize everything we got until now since this will make it easier for other forum members to get the values if they need:

The markings on my PCB are as follows:

• U1233-26500
• REV00Z (it could be 007. It is hard to read the last character since the fuse holder is soldered on top of it)
• MSS-B white sticker

C50, C98 and C99
I guess whe're all on the same page these are 100uF 16V SMD Aluminum Electrolytic Capacitors.
Mine are marked as 275-100-16E so I believe the 245-275 is the date code. I'm just unsure about the E marking if this means anything special about it.

C52
Missing

C59
26µF

C60
27µF

C61
9µF

C62
176nF

C68
25µF

C69
16µF

C206
Mine is intact. Will have to remove it to measure. Stay tuned...

C207
Mine is intact. Will have to remove it to measure. Stay tuned...

CR18
Still missing.

CR22
I did some research and the marking I have is "PD>" - This seems to be a BSS84L MOSFET
https://www.onsemi.com/download/data-sheet/pdf/bss84lt1-d.pdf
Although I'm pretty confident this is our guy and the tiny dot we see on the marking indicates it is a pb-free package, I couldn't find any datasheet that covers the > marking. It seems to me that it can be only the date code though.

R3, R4, R5, R6 and R7
They all measured 2M ohm. Since they're in series, total series resitance is 10M ohm so this confirms 2M each.
The color coding is red-black-black-yellow-brown so they have a 1% tollerance.

Cheers