EEVblog #170 – Agilent U1272A Multimeter FAILPosted on May 19th, 2011 13 comments
Dave has rotten luck with test gear for review failing.
What’s up with his Agilent U1272A Multimeter?
See a follow-up video from a viewer who posted this:
Sorry to hear, are you going to send it back to the Agilent? It looks like some troubles with pull down resistor or switch.
if you want to get rid of it, I would take it
It acts like a flaky. Was it pretend soldered in Malaysia?
Dave, you broke it!
I have recently ordered an Extech EX470 meter and the first unit arrived in a similar condition – depending on the mood it was either working OK or just showing garbage or locking up. In my case it is most likely a fault in the main function switch – pressing on its rim sometimes restores the correct function. That could be your issue too – poor contact on the switch causing issues and when your turn it on/off again it starts to work.
Fortunately the shop has replaced mine free of charge and I even got to keep the faulty one, so I am happy.
BTW, you should update your recommendations for meters – the Extech EX330 is very hard to find, most distributors do not stock it for whatever reason. That’s why I have actually got the 470 – a free upgrade to 200 EUR meter, because the 330 was not in stock!
Regarding your follow-on video of the Agilent U1253 OLED meter; we’re definitely on the same page regarding 9-v batteries. The $450 list price of the U1253 is just entry to the club. The buyer will spend another fortune in batteries–even rechargeable ones.
The U1253 is out of my price range, but I’m looking hard at the $200 U1241. Ironically, it’s major selling point, to me, is that it takes 3 AAA batteries instead of the usual 9-v. Three AAA batteries have more energy and cost less than a 9-v. I’m hoping that more instrument makers pay more attention to battery costs.
Where have you been Dave? Long time no Blog…
Are you sure that the switch is still in good contact with the PCB after your tear down?
I ran into a very similar issue before with another multimeter, and after I carefully cleaned the switch and the contact surface, everything was back to normal again.
Agilent will definitely get you a replacement without questions! Go ahead and check it out. One-off and intermittent signing off!
WoW, Agilent gone bad, too much defects, before was their Scope now the multimeter. they should carefully check their products if it cost that much or nobuddy will trust is anymore. Thanks dave for sharing .
Agilent makes a lot of crap since separating from HP.
I had some E4402 spectrum analyzer. All have a strange defect : when using them on 12V power, sometimes, on power on, they lose the calibration, and sometimes are off 20dB without warning.
Agilent checked the HW (and charged it!), found nothing, and did not want to investigate further !!
Never buy anything branded “Agilent” again.
It went just crap.
i have seen this with other multimeters ( fluke’s )
that rotary switch is basically a D/A convertor. a resistor ladder as switched around and depending on the position of the ‘wiper’ a different voltage is applied to the meters processor switch input. Saves pins.
Here is the problem. that wiper shorts a node on the PCB to ground. IF any kind of debris goes between the wiper and that node you get a strange reading on that pin and the cpu can;t decide what to do. it just cycles between modes.
some PCB’s have a carbon layer on those pads. that carbon forms dust after many years and is spread by the wiper action causing strange modes.
the solution : pop the board out and clean the contact are with an eraser. wipe clean with some isopropyl alcohol. reassemble.
and NEVER, EVER ! use contact cleaner or grease on such switches !
I’ve had up close and personal experience with two meters (a U1273A – the OLED one, and a U1272A) in this series in the last week. A few comments:
- Both of these are expensive meters even thouth the 1272A was “free” as part of promo for buying a power supply. Yet they come with cheesy (I think) no-name batteries.
- Both of them are sealed (IP54.) In both meters, I found junk (a wire fragment in one case and a bit of cloth) on the o-ring seal in the battery compartment.
I’ve been traveling so I haven’t had a chance to exercise either of them in any serious way.
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