UEI DL479 problem. - Page 1
Forum section: electronics / testgear

author: highpower
author_rank: Regular Contributor
timestamp: July 18, 2023, 05:56:31 pm
content: I was "gifted" a UEI DL479 clamp meter (now discontinued) from a tool distributor several years ago. It has sat unused in one of my tool bags for the most part, since I have several other higher quality meters that I like to use instead. I wanted to start using the UEI meter as a general purpose ohmmeter - continuity tester for around the house. When set to read continuity the meter works normally for a minute or two and then suddenly the beeper sticks on and stays on. At the same time the display starts showing all kinds of weird readings and multiple indicators (V, mV, Hz etc.) come on when they are not supposed to. It will continue to beep until shut off, then starts working normally again for another minute or so. Then the symptoms repeat all over again. I discovered the meter will do the same thing even with no leads attached to the meter at all.And yes, new batteries are installed.All the other functions on the selector switch are working normally and don't give any weird readings or indicators. I've searched the net for days and haven't been able to find anyone that have had the same issues with the DL479. In fact I can't really find any information about this meter other than a data sheet.Any ideas?

author: tautech
author_rank: Super Contributor
timestamp: July 19, 2023, 08:58:57 am
content: Quote from: highpower on July 18, 2023, 05:56:31 pmFirst I would edit your opening post to delete all the blank space.Then it's always caps as some would say and if not, zebra strips.

author: highpower
author_rank: Regular Contributor
timestamp: July 21, 2023, 01:16:37 am
content: Don't know how all the blank space got there but I certainly didn't add it intentionally. Just the attachment.Somehow I doubt a zebra strip is going to cause a continuity beeper to stick on so I'll focus on the caps to begin with I suppose. Thanks for the input.

author: J-R
author_rank: Super Contributor
timestamp: July 21, 2023, 04:24:18 am
content: Interesting issue. At least start with the basics and check/clean battery and switch contacts, look for loose solder joints, PCB contamination and anything visually damaged.

author: highpower
author_rank: Regular Contributor
timestamp: July 21, 2023, 02:05:59 pm
content: Quote from: J-R on July 21, 2023, 04:24:18 amIndeed. The strange thing is this is essentially a new in the box meter that has been sitting unused with no batteries installed. I put a new set of batteries in it to do some continuity checks and after a few tests when I removed the probes from the wires being tested the buzzer would not stop. I split the case to have a cursory look inside and it is spotless inside which is what I would expect to see in a new meter. I wanted to check the switch contacts but couldn't figure out how to remove the dial and get it apart and didn't want to force anything. I didn't have the time to spend on it at that point so I'm just now getting back to it. It seems to have a hexagonal brass center post that runs through the center of the switch. It looks like it should just push out but it doesn't budge. No schematic is available and the only videos I have been able to find on YouTube with the same symptom (stuck beeper) all seem to show a cheap pocket meter with a burned resistor. Unfortunately for me they are also in a language I do not speak or comprehend so there is that barrier as well.

author: J-R
author_rank: Super Contributor
timestamp: July 21, 2023, 06:18:30 pm
content: What batteries are you using?

author: highpower
author_rank: Regular Contributor
timestamp: July 22, 2023, 01:56:48 am
content: Energizer MAX alkaline AA