BK Precision 2712 Missing Segments LCD Repair - Page 1
Forum section: electronics / repair

author: Pedrofabian
author_rank: Contributor
timestamp: January 28, 2022, 04:27:35 am
content: Hello, I have a B&K Precision Toolkit 2712.Its missing the bottom segments of all five digits. Other than that everything seems to work great!After opening it up, it appears the glass reflective LCD panel corner chipped, taking one of the little conductive fingers with it. Pictures attached.I'd hate for this meter to go to waste for that, it would make a decent little gift or something.I'd assume not, but any hope for some kind of remedy?There's definitely no market for parts or anything that I can find.I'm not really hurting for meters, so risky / destructive solutions are welcome-- edit: Looking closer at the pics, looks like the ohms segment is missing too. Also I have the broken piece

author: Pedrofabian
author_rank: Contributor
timestamp: February 06, 2022, 09:54:13 am
content: Bump

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 06, 2022, 05:09:48 pm
content: How is the LCD connected. Is it perhaps and elastomer strip?Disassemble and check the connections.

author: shakalnokturn
author_rank: Super Contributor
timestamp: February 07, 2022, 09:19:32 pm
content: That's a tough one!If there's any ITO left accessible at all:Try applying a little conductive paint (graphite / nickel / silver) to it to bring the connection out to the thickness of the other glass plane, then you may be able to constrain the zebra to make enough contact on that axis.

author: inse
author_rank: Super Contributor
timestamp: February 08, 2022, 05:28:25 am
content: Use a marker pen to fill the missing segments 😀Looks like the only remaining option

author: Gyro
author_rank: Super Contributor
timestamp: February 08, 2022, 10:17:04 am
content: From your photo, it's really difficult to get context of how the display is terminated (I can't see any discrete ITO segments that might contact a zebra strip for instance). One idea might be to carefully build up the broken corner with epoxy or whatever to give a flat mating surface with the zebra strip. That would give you something to put conductive ink onto, to connect with any remaining conductive trace.Another thought. Have you actually checked that there is a PCB trace that is aligned with that broken corner? Normally the traces start a little way in from the ends. It might be that there is just some contamination on the zebra strip and the chipped corner is just a coincidence, especially if there is no evidence that it got chipped after manufacture.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: February 08, 2022, 12:00:36 pm
content: I agree with GyroTake it apart and see if the zebra elastomer strip is in place correctly and clean it.You can clean the edges of the strip with an exacto knife. Scrape the conductive surface

author: Pedrofabian
author_rank: Contributor
timestamp: February 13, 2022, 02:08:30 pm
content: Sorry, didn't see these replies!Yes, this unit is as a lot of handheld meters, its a zebra strip that mates to the board. I've done all manner of cleaningbut I don't think it will help. I'm sorry the picture didn't give much context. Essentially thats a (very) close up of the LCD, which is a traditional glass pane with little conductive fingers that touch the Zebra strip and the conductive pads on the board. The part that chipped was one of the pads. I've attached a picture for better context.

author: Pedrofabian
author_rank: Contributor
timestamp: February 13, 2022, 02:11:10 pm
content: Quote from: shakalnokturn on February 07, 2022, 09:19:32 pmHmmm interesting, I'll see if I can't try that.

author: Pedrofabian
author_rank: Contributor
timestamp: February 13, 2022, 02:13:22 pm
content: Quote from: Gyro on February 08, 2022, 10:17:04 amSorry I tried to get the best angle I could. There is 100% an ITO segment on the chipped piece of glass, which I still have. And you can't see it well in the picture but there might be a tiny bit left.

author: jbeng
author_rank: Regular Contributor
timestamp: February 14, 2022, 04:49:38 am
content: Honestly, if the ITO trace is broken off the LCD, I can't see any way to reliably repair it. I'd check with B&K to see if they can provide a replacement display.https://www.bkprecision.com/support.html