Possible for newbie to fix autoranging on a Mastercraft multimeter? - Page 1
Forum section: electronics / beginners

author: Hogwild
author_rank: Regular Contributor
timestamp: June 30, 2019, 10:51:34 pm
content: Hi everyone:I have quite good soldering skills, but next to no understanding of electronics theory. My (ver. 1) Mastercraft 52-0052-2 multimeter still works, but the autoranging has stopped working, at least most of the time.I plan to do a visual inspection of the inside, but is there anything in particular I can look for with the symptom being autoranging not working, or am I wasting my time? Is there anything in particular which frequently causes autoranging to stop working that is fixable?Thanks

author: GerryR
author_rank: Frequent Contributor
timestamp: June 30, 2019, 11:42:50 pm
content: If it is working some of the time, I would be looking, with a magnifying glass, for cold (frosty looking) solder joints. Touch them up and you should be good to go.

author: Hogwild
author_rank: Regular Contributor
timestamp: July 01, 2019, 03:38:07 am
content: It rarely works, but it still does occasionally. Thanks, I will look for cold joints and post back with my findings.

author: MosherIV
author_rank: Super Contributor
timestamp: July 01, 2019, 06:57:53 am
content: HiAuto ranging is usually done in software. The software usually checks inputs of highest range and if not near full scale goes and checks next range down, repeats until it find range that is not over flowing.Clean the probe end, connectors and the sockets in the dmm.When you say works sometimes, is this on Volts or Volts and Ohms?

author: Hogwild
author_rank: Regular Contributor
timestamp: July 01, 2019, 08:52:45 pm
content: Hmmmm...good question. I'm not sure. I've mostly only measuring resistors lately with ohms. I will try both and see what happens.

author: GerryR
author_rank: Frequent Contributor
timestamp: July 01, 2019, 09:34:14 pm
content: Start with the highest range to see if you get a reading, then drop down a range, etc. Software doesn't work intermittently; it may be starting at the highest range, not "seeing" anything and therefore doesn't drop down to the next range. Whatever is switching between ranges, small relays, solid state switch, is causing the problem. My bet is on a bad "switch" or a cold solder joint. I had the same thing happen to me on a process meter and found several cold joints on one of the surface mount chips. Repaired and back in business.

author: Hogwild
author_rank: Regular Contributor
timestamp: July 02, 2019, 02:40:58 am
content: I took it apart and took a good look inside. It took me a while, because at first, the dial and the ball bearings fell out and I had to figure out how to put them back. It's hard to tell when there are cold solder joints with lead-free solder, as they typically look less shiny, depending on the viewing angle.There are what look like two transistors that don't have solder on the top side of the board. I'm wondering if I should touch those up with solder. There are also two larger solder joints just underneath the LCD. I don't know what those are for, but one of them looks kind of cold (again hard to tell with lead-free).I'll look further and post back.

author: Hogwild
author_rank: Regular Contributor
timestamp: July 16, 2019, 03:14:17 am
content: I finally took the unit apart again, and used my new soldering station to clean up any joints that looked cold. It wasn't easy-a few of the joints definitely looked like there were impurities during their initial soldering.I don't think it's changed anything. That being said, I noticed that it consistently behaves the same way. When you select resistance, it seems to auto-range. When you select a range, it doesn't work within that range, even if the resistance being measure is within that range.Suggestions?

author: GerryR
author_rank: Frequent Contributor
timestamp: July 16, 2019, 11:30:02 am
content: You confused me somewhat with your last statement. If you select ohms, it auto ranges, and gets the correct value(?). Once you select a range, it is then in manual mode, so that particular range isn't working in manual mode; will it read correctly in another range, though not with the same accuracy? Sounds more like a manual range problem and not an auto range problem.

author: Hogwild
author_rank: Regular Contributor
timestamp: July 29, 2019, 02:14:20 pm
content: I didn't even know it was supposed to work like that. I could SWEAR that it didn't when I first got it years ago. I will try it on other functions. So far, I've only tried autoranging on resistance since I believed there was a problem.I'll try to do some voltage or current tests and post back.On an inexpensive meter like this, how accurate is capacitance?

author: rstofer
author_rank: Super Contributor
timestamp: July 29, 2019, 02:44:34 pm
content: I suppose the User Manual would answer some of your questions:http://hogan53.net/specs/52-0052EN.pdfEverything (including Capacitance) is autoranging as long as the range button selection is in Auto. Page 1 Paragraph 7

author: Hogwild
author_rank: Regular Contributor
timestamp: August 01, 2019, 10:35:20 pm
content: I'll asume for now that my meter is working okay then.Thanks everyone.

author: Jwillis
author_rank: Super Contributor
timestamp: August 02, 2019, 05:21:36 am
content: Quote from: Hogwild on July 29, 2019, 02:14:20 pmI have several of the Mastercraft multi meters and they test capacitance fairly accurately . Just a couple issues with Mastercraft is ,because they are all re branded, its hard to get accessories like thermo probes and fuses from Canadian Tire..For example ,although not branded Mastercraft ,the Maximum 052-1898-4 is manufactured by Mastech.And a very old Mastercraft I have is a Brymen.Numbers are worn off so I can't give you a model number. Both Mastech and Brymen have very good products.For installing the little balls I found that just a dab of dielectric grease to stick the balls to the springs.Then set the board on top holding the switch and front cover facing down. Hope this helps in the future.