Got me a New U1253B - Page 1
Forum section: electronics / general

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 29, 2012, 09:09:57 pm
content: Wow what can I say. The Display is outstanding. The update amazing, It sooo much better than my old meter. But then my old meter was only $20.However the Battery life sux. I mean really sux!.So With my new found knowledge of switch mode DC-DC converters, I was thinking of making a small PP3 sized PSU to fit inside the battery compartment. Now not wanting to destroy my shiney new Multimeter, any sugguestions as to what I should design into my PSU.I'm thinking of using the LM2574M-ADJ (I recently had another thread about a DC-DC issue and this converter came out tops) set it to 8v and use the meters 24v battery charger as the source.CheersJfp

author: ejeffrey
author_rank: Super Contributor
timestamp: May 29, 2012, 09:42:19 pm
content: Quote from: johnnyfp on May 29, 2012, 09:09:57 pmYou shouldn't. Hand held multimeters do not have isolation between their guts and the input signal. They rely on the plastic case and sealed construction to provide safe isolation and allow floating measurement. Connecting an external DC supply into it defeats the purpose of that insulation. This is why meters generally have admonishments to remove the test leads before opening the battery compartment.If you do so, you would definitely need to build an isolate (transformer coupled) supply, but even then it would be very unlikely to meet the same safety standards as the meter is intended.

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 29, 2012, 09:50:45 pm
content: Mmmh. What about a dual purpose PSU.I mainly work with 1-24v anyway and nothing really higher. If I do then I could unplug the unit and it switch back to battery and be Isolated.How do bench top Multimeters get round this issue anyway?Maybe I should go down the route of fitting a Lipo instead but then that would live outside the battery compartment (PP3 sized ones don't seem to have any performance gains over the exisitng NiMH one).CheersJfp

author: EEVblog
author_rank: Unknown
timestamp: May 29, 2012, 09:58:57 pm
content: Hacking such a nice meter (or any meter) is just bad news, I wouldn't do it.Dave.

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 29, 2012, 10:03:48 pm
content: There will be no hacking involved as per say. I will Makerbot a new battery cover. So nothing is damaged. I could even make orange bits in itI think I may go down the Lipo route. Seems the easiest and safest solution.Jfp

author: EEVblog
author_rank: Unknown
timestamp: May 29, 2012, 10:17:44 pm
content: Quote from: johnnyfp on May 29, 2012, 10:03:48 pmSafe until it explodes in your hand from an overload.The point is, these meters are designed to be safe under gross overload conditions. ANY modification at all is potential bad news.As I mentioned in my review, it's not an everyday use meter, it's the Ferrari you get out when you need to race.Get another everyday user meter with better battery life, and use a 9V lithium in there. Used sporadically, the battery should last a long time.Dave.

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 29, 2012, 10:44:14 pm
content: Suppose so.I was a Moth to a shiney light on this purchase. I will have to live with it.But it is nice!.Jfp

author: Baliszoft
author_rank: Frequent Contributor
timestamp: May 29, 2012, 11:05:01 pm
content: That's why i got myself a 1252B. Its battery life is reasonable.

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 29, 2012, 11:08:24 pm
content: Yeah I know. But there was not much price difference between the two, and Shiny won. Doh!Jfp

author: tom66
author_rank: Super Contributor
timestamp: May 29, 2012, 11:12:31 pm
content: I wonder if the LCD and OLED displays are interchangeable parts? In Dave's teardown it seemed that the OLED board was an OEM part with a custom interface... it would make sense to use the same motherboard and just change the display part.Would involve taking it apart but might be good if you need to e.g. set it up for making long term measurements or if you know you won't be near a power source for a while.I think the OLED is very pretty, but is more suited to a bench meter with constant power (which usually uses VFD.) For a portable instrument battery life is essential so compromises must happen.

author: Baliszoft
author_rank: Frequent Contributor
timestamp: May 29, 2012, 11:14:48 pm
content: Quote from: johnnyfp on May 29, 2012, 11:08:24 pmI was tempted, too. But finally i did not give in. Love the meter though. It is just what i needed, precise measurements!

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 29, 2012, 11:28:38 pm
content: I am weak willed, and it doesn't help when Dave keeps showing us Nice things!(In a desperate and despondent expression) "Curse you Dave and your Wiley way's, tempting us with Nice things!"Jfp.

author: nanofrog
author_rank: Super Contributor
timestamp: May 30, 2012, 06:46:28 am
content: Quote from: johnnyfp on May 29, 2012, 10:44:14 pmAs mentioned, you could use Lithium disposables, or get a couple of LSD (Low Self Discharge) NiMH and a charger, and rotate (should allow to always have one charged battery ready to go). Not that expensive to do, and cheaper than disposables over time.Quote from: Baliszoft on May 29, 2012, 11:05:01 pmSame.36 hrs isn't exactly wonderful, but it's better than 8 hrs with the OLED version. Spare batteries would mitigate the issue with either, but they won't have to be swapped as often with the LCD version.

author: Baliszoft
author_rank: Frequent Contributor
timestamp: May 30, 2012, 08:40:31 am
content: Quote from: nanofrog on May 30, 2012, 06:46:28 amFor me it is enough to fiddle it with all day (for more than a week or so) and if i see that the battery is below 50% then i just charge it overnight. Most of the times the battery meter is on 75%, so when it begins to decrease i still have a day.

author: grenert
author_rank: Frequent Contributor
timestamp: May 30, 2012, 02:07:05 pm
content: Quote from: tom66 on May 29, 2012, 11:12:31 pmI think that is very unlikely. The U1252B (LCD) has a segmented display, while the U1253B (OLED) is bitmapped.

author: nanofrog
author_rank: Super Contributor
timestamp: May 30, 2012, 08:07:33 pm
content: Quote from: Baliszoft on May 30, 2012, 08:40:31 amMe as well. The only reason for keeping batteries at the ready, is so I don't have to stop what I'm doing and wait a few hours on the charger when I get into a project on the bench and discover the meter's dead or will be before I'm done. Battery swap is much faster.The comment on the usable hours is compared to other meters which tend to offer better battery life (even the 287/9 gets 100 - 200 hrs.). Not the end of the world by any means (I'm quite happy with mine), but it does make the U1252/3B a little less convenient by comparison.

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 30, 2012, 08:13:54 pm
content: So if the 52 is the same as the 53 (except for the display), how does the Setup and menu system work on a segment display?Jfp

author: nanofrog
author_rank: Super Contributor
timestamp: May 30, 2012, 09:15:46 pm
content: Quote from: johnnyfp on May 30, 2012, 08:13:54 pmEnter the Setup Mode, and it displays text (can be a mix of upper and lower case letters due to the segmented display, but it works well enough). For example, if I want to adjust the Refresh Hold, I scroll through the menu items using the left & right scroll keys (< and >) until it displaysrHold, then scroll through the up and down scroll keys until the desired value is displayed. Then press the Hz key to save the setting.Not as pretty as a matrix display, nor can it show entire menus (just one setting at a time), but it's not hard at all.If you want further detail, graphics in particular, go to Agilent's site and download the manual (good idea to print one out if you get one IMHO, as just a Quick User's Guide is in the box). Menu settings start on pg. 74, and a few pages later, show graphics of what the various settings would look like on the screen.

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 30, 2012, 09:20:08 pm
content: Was just curious. Because there was a lot of data on my 53, and wondered how they could represent a lot of that on a 8 segment display.Us young wipper snappers like all this new fangled touch screens and dot matrix displays, oh wait I'm not young anymore, damn will have to downgrade.Jfp.

author: nanofrog
author_rank: Super Contributor
timestamp: May 30, 2012, 09:59:57 pm
content: Quote from: johnnyfp on May 30, 2012, 09:20:08 pmSo you're prone to falling for gimmickry then...I'm not *that* old... (like many here it seems, I started with electronics as a kid). But I know what you mean. A full menu display is nice, but it's not absolutely critical in this case (menu system isn't that big, nor is it used to choose functions - dedicated soft keys do that).The LCD version has the same feature set as the OLED version, but with improved battery life (BTW, OLED has a much shorter lifespan than LCD if you're not aware <~14k hrs vs. ~60k hrs for LCD>). Keeping spare batteries can solve issues of one being dead when you go to use the meter, or if it dies in the middle of doing something, so for bench use, either would be just fine.I just don't think the OLED offers enough to warrant buying it over the LCD version (had it a bunch of really useful features the LCD was missing, that would have been a different matter).

author: johnnyfp
author_rank: Frequent Contributor
timestamp: May 30, 2012, 10:17:52 pm
content: Yeah I know.In 14k hours usage time I will be back on the forum complaining that my pixels have stopped working. "Is that 240v I'm reading or 40v........BANG!"But it's still ever so pretty.Jfp.

author: nanofrog
author_rank: Super Contributor
timestamp: May 30, 2012, 11:01:17 pm
content: Quote from: johnnyfp on May 30, 2012, 10:17:52 pmYeah, that wouldn't make me happy either.But even if you used it 8hrs/day for 5 days a week, then you'd still get ~6.7 years out of the display. So you may not feel as bad. Especially if something newer and better has come along by then.I want more than that though, typically 20 years at least.And LCD should be able to do that, and saved me a little cash in the process (that I can put towards more parts to smoke).