Debris found in Brymen BM235 (non EEVblog edition) should I be worried - Page 1
Forum section: electronics / general

author: PeterMadach
author_rank: Contributor
timestamp: October 03, 2022, 01:59:17 pm
content: HelloI've purchased a retail BM235 and noticed the mA fuse was in a bit wierdly placed, being very close to the red cable connecting the two PCBs. When I slid it to the middle position, a metal piece fell out from the meter. I made photo of the area, and tried to capture the piece that fell out, my phone struggled finding focus, sorry about that. To me it looks like a cable crimp maybe. I tried looking at high res photos of the meter, and everything seems fine, altho I haven't disconnected the two PCBs. So far functionality seems fine, altho I haven't measured any current with it. Anyone can confirm what it is?

author: Fraser
author_rank: Super Contributor
timestamp: October 03, 2022, 02:26:48 pm
content: Sorry, a better image is needed. Try moving further away from the mystery metal piece and use a torch to help the phone find focus. Take the picture with good focus and we can zoom in for more detail. There is usually plenty of resolution for zooming. Pictures of the metal piece from different angles also helps if it is a 3 dimensional part.

author: PeterMadach
author_rank: Contributor
timestamp: October 03, 2022, 02:57:24 pm
content: Thanks for the reply.Phone really struggling, the thing is about the size as a grain of rice (closer to sushi than basmati lol), tried some different angles and using a piece of paper as background. Let me know if these are any better.

author: Fraser
author_rank: Super Contributor
timestamp: October 03, 2022, 03:17:41 pm
content: I have looked at the better pictures… thanksHmmm that looks like a clip of some sort. I would certainly want to know where in the meter that belongs. First thought was a retaining clip for the meters knob but the size is not right. Definitely looks like some form of retaining clip though.Hopefully someone will recognise this item now that it’s complex shape is clearly visible.Thank you for providing the better imagesFraser

author: PeterMadach
author_rank: Contributor
timestamp: October 03, 2022, 03:36:15 pm
content: Do you think its possible it was supposed to be the cable clamp that seems to be on that end of that cable? (see pic below) The cable on mine is not crimped on the end that connects to the base PCB.

author: Fraser
author_rank: Super Contributor
timestamp: October 03, 2022, 03:41:03 pm
content: I have just realised what that mystery clip is ! I suspect it is the internal parts of a DuPont pin header shorting linkThe question is, was this part of the shorting link left inside the meter by accident after a calibration/check operation or should it be installed ? I believe it was left inside in error otherwise there would also be the plastic outer shell. It likely fell out of a DuPont shorting link when it was pulled off the DuPont header pins after testing. J1 is shown in your last PCB image… that is the sort of pin header that this clip would have been installed on.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: October 03, 2022, 04:02:48 pm
content: Here is a link to an RS datasheet for a DuPont bridging/shorting link and it contains a cut away drawing of the connector. This confirms my belief that you found the inner metal part of such a bridging link inside your meter. It could well be that J1, or another pin header needs to be shorted for a particular production test. I see no such bridging link fitted whilst viewing the EEVBlog repair video that Dave did, so presumably none are fitted once the meter leaves the factory.https://docs.rs-online.com/c67f/0900766b815836ba.pdfFraser

author: PeterMadach
author_rank: Contributor
timestamp: October 03, 2022, 05:03:04 pm
content: I can confirm it is a perfect match for that jumper. I'm 99.9% sure now that this won't affect anything. Probably a good thing I caught it too, God knows what it could've done if it shorts something during operation. Thanks for checking it mate!