Keithley 2015 Benchtop DMM Display Polish - Page 1
Forum section: electronics / repair

author: 2bluesc
author_rank: Contributor
timestamp: May 13, 2017, 07:03:05 pm
content: Hey all,I purchased the infamous Keithley 2015 from eBay for standard DMM duty and some audio projects. It showed up in good electrical shape and has calibration stickers on it from 2014 and 2015 and agrees with my other test equipment, so that's good. But, the plastic display was quite scratched and difficult to read the VFD behind it. I had heard of a number of people replacing the VFD, but I didn't think mine was that dim and thought some polish might help.Figured this is pretty generic process and anyone with a tired looking DMM could follow similar steps. Except of course those with proper glass displays that don't get scratched by just looking at them... but hey, it's only a $4k DMM.After some disassembly I restored it in a few steps:Mask off the edge of the display, Keithley Logo, and Model text to avoid removal during sandingWet sand the display flat with 2000 grit sandpaper and a Dura-Block AF4400 I cut down to size to get the deep scratches out and while keeping the display flat and not wavyNOVUS 3 Heavy Plastic Heavy Scratch RemoverNOVUS 2 Heavy Plastic Fine Scratch RemoverNOVUS 1 Plastic Clean and ShineBack to work!When you're done with the Dura-Block AF4400 makes an ok DMM stand to prop it up for easier reading since almost none of these have the original handle anymore.The display is hard to photograph because it either looks bad or it looks fine with little in the middle. But, in use it's a night and day difference. The DMM went from feeling used and abused to aged and dignified, as any VFD display should feel these in this day and age.If I could do it over again, I'd spend a little bit of time sanding the edges of the display. They look ugly and rough in the photos, but aren't noticeable in real life.I've attached the highlight photos but have a bunch of pictures in anImgur album.Thoughts?

author: nctnico
author_rank: Super Contributor
timestamp: May 13, 2017, 11:39:21 pm
content: In a similar case I used regular scratch remover intened for cars. That seems to work equally well with much less work.

author: xrunner
author_rank: Super Contributor
timestamp: May 14, 2017, 12:00:04 am
content: I think it's a fine job, nice work saving the logos too.

author: TiN
author_rank: Super Contributor
timestamp: May 14, 2017, 11:47:35 am
content: Good job

author: HighVoltage
author_rank: Super Contributor
timestamp: May 14, 2017, 04:18:33 pm
content: Looks really nice.This must have taken a lot of time to get it so nice and not touching the name and model number writings.

author: 2bluesc
author_rank: Contributor
timestamp: May 14, 2017, 08:15:47 pm
content: Quote from: HighVoltage on May 14, 2017, 04:18:33 pmThanks. Most of the magic was having the foresight to mask the logos with some tape over them before I started. On the final polish, I removed the tape so there were no edges visible.

author: Zucca
author_rank: Unknown
timestamp: May 15, 2017, 10:31:43 am
content: I would have try to polish with toothpaste and to get the shiny back mineral oil...

author: coromonadalix
author_rank: Super Contributor
timestamp: May 15, 2017, 09:18:22 pm
content: just done a meter for this problem, i've taken a 1000 grit sand paper with water, made a good run all around in circular motion the plastic 3 times, taken a 2000 grit with water, circular motion 3 times, after that aplied novus 2 3 times, and bam like new finishTried the tooth paste for my car headbeams, applied 5 times with humid cloth, worked like a treat loll the Aim brand seemed like a fine grit ...