Kilter 128 pocket multimeter teardown (similar to UEI DM5B) - Page 1
Forum section: electronics / testgear

author: Robomeds
author_rank: Frequent Contributor
timestamp: September 26, 2015, 02:48:06 pm
content: A while back I came across an ebay auction for something like 10 or 12 of these meters as a lot. The per unit cost was something like less than $5. What the heck. I’ve basically given the things away over the past few years and I’m down to my last one. I’ve really never used this one but I figured, why not do a tear down (and adjustment).As labeled this is just a generic “128 Multimeter”. It’s about as simple as they come with just a selector switch and a set of removable probes. No CAT rating but I’m going to guess the cat folks wouldn’t let it get too far given the input terminals don’t accept shielded banana plugs.Overall the thing doesn’t feel too bad as far as this sort of meter goes. I mean the switch feels and works better than those on many larger meters. The display is reasonably large and quite easy to read. The contrast could be better but that might be an issue with older batteries. The leads feel like they have VERY thin wires but otherwise they are OK for a cheap meter.The only really annoying trait of this meter is the thing beeps when it decides it’s out of range. That wouldn’t be a big deal except that the DC range defaults to mV and thus just background noise is enough to bump it out of mV range every 5 seconds or so… beep.Disassembly isn’t much. Three screws on the back then remove the back cover. That exposes the back of the PBC which is just raw board. The PCB is not just populated only on one side, it is a single layer board. Thus the only thing you see on the back is the retaining clip which holds the selector switch against the PCB.Remove the retaining C-clip and the selector pops out the front. At that the PCB can be lifted out. The assembly quality is better than I’ve seen in some cheap meters. The IC is a JRC chip. Note that the board does have both a PTC and four diodes for input protection. No need for fuses as the thing doesn’t measure current.The single trim pot would normally be accessed through the front of the meter. The LCD window covers the access hole. That same hole would be used for buttons in the better versions of this meter. Speaking of trimming, I decided to adjust the thing just a bit. In comparison to my Fluke 187 the meter was 0.1V out when measuring an 18V battery. Trimming is just via that trim pot but it turned into a guess and check game. At the factory they probably trim through the hole under the LCD plastic. I didn’t want to rip that off so I did a guess, rebuild, check process. The meter now agrees to 0.01 when measuring at same 18V battery. That should be good enough for me.The input terminal are securely soldered to the bottom of the PCB. However, they don’t accept shielded banana plugs. At least the included plugs leave no exposed metal when placed all the way in.In use, the meter is almost a good pocket meter. I’ve already mentioned the annoying beep when in DC voltage mode with no leads attached. The resistance auto ranging is also slow, taking about 4 seconds to go from open circuit to shorted. The continuity buzzer is hard to hear but prompt. It seemed a bit scratchy but not too bad. The hard to hear part can be an issue. I would rather have the leads hardwired into the meter. Since the terminals are on the bottom of the meter, typically you don’t leave the leads in the inputs. This slows the “get it out and use it” process more than I would like. Anyway, I guess it’s OK for a cheap meter. I used to keep one in my car but it was given away and replaced with a Centech cheapie.

author: Robomeds
author_rank: Frequent Contributor
timestamp: September 26, 2015, 02:54:44 pm
content: More pictures. In one you can see the cheap folding case that came with the meter.Interesting to see the guts as compared to my old Radio Shack pocket meterhttps://www.eevblog.com/forum/testgear/micronta-pocket-multimeter-teardown/msg263947/#msg263947