Fluke 117 LCD low contrast - Page 1
Forum section: electronics / testgear

author: M0UKD
author_rank: Contributor
timestamp: November 10, 2017, 11:06:56 pm
content: Hi all.I have a Fluke 117 and as known, the 11X series have poor LCD contrast (Compared to my 179, it's very bad). I was wondering if it would be possible to somehow modify the meter to increase the LCD contrast, like an LCD current increase perhaps?Is there anyone with knowledge on Fluke LCD drivers that may be able to advise? I love the meter, but the contrast is horrible when viewed straight on, I always find myself looking at it from a silly low angle to make it look OK!Cheers, John.

author: Muttley Snickers
author_rank: Unknown
timestamp: November 11, 2017, 01:19:00 am
content: I have heard of this problem before but never seen it and own both a Fluke 115 and 117, in my case though they are probably up there as two of the better viewing meters that I own, anyway a picture saves a thousand words so a couple of images below of other meters for comparison, all of these meters still retain the screen protectors intact but the one on the 117 is not the original. After these images were taken the BM-235 pictured below was modified to increase the contrast which made a tremendous improvement to the screen clarity.Another thread is linked below which mentions a similar display issue including some handy information in relation to the zebra strips, in my view it would be nice if manufacturers could include a trimmer for the contrast adjustment so people could tweak the display for their own individual requirements, probably too much to ask for I suppose.Fluke Problem Thread.https://www.eevblog.com/forum/testgear/fluke-problem/

author: opablo
author_rank: Regular Contributor
timestamp: May 14, 2025, 05:29:44 am
content: I hope somebody can help with this issue.I also purchased a F117... which I love... accuracy looks great; speed feels great... has the right features... It's becoming my most used meter...But the LCD contrast is clearly incorrectly biased...It's bad enough for me to risk modding it if anybody can tell me which resistor should be changed to tweak the lcd contrast bias

author: BeBuLamar
author_rank: Super Contributor
timestamp: May 14, 2025, 10:11:36 am
content: I have used a number of 179 and 117 and I found the contrast to be the same. I only find the 287 and 289 contrast are too low.

author: AVGresponding
author_rank: Super Contributor
timestamp: May 14, 2025, 06:33:10 pm
content: Quote from: BeBuLamar on May 14, 2025, 10:11:36 amThe contrast is adjustable on the 287 & 289 using the up and down arrow keys?

author: HP45man
author_rank: Newbie
timestamp: May 15, 2025, 04:02:29 am
content: Hi John, I am new to this forum so I apologize in advance because I do not know yet how to properly quote someone but I believe Muttley Snickers nailed it when he mentioned "Zebra Strips", originally known as elastomer strips for connecting the LCD glass with the PCB. On my Fluke 79 (which remains retired most of the time now with the same issue) after it sits on the shelf for a year or two, will develop the same problem with the display. After disassembly I usually notice a white residue on the PCB contacts that mate with the elastomer strip connecting to the LCD (for some dumb reason the contacts are heavily tinned with a rather thick layer of solder). I clean the contacts with alcohol and sometimes very carefully clean the rubber strip (be sure to gently blow away any threads from the cotton swab). Problem solved - at least for another year or twoI am curious; you mentioned the 11x series are known for that problem. Has it been like that since it was new, or did it develop with time like my 79 did?Good luck,Charles

author: BeBuLamar
author_rank: Super Contributor
timestamp: May 15, 2025, 11:55:23 am
content: Quote from: AVGresponding on May 14, 2025, 06:33:10 pmThe adjustment is called contrast adjustment but it doesn't adjust the contrast. When you make the number darker the background is also darker. The difference between the the numbers and the background isn't as good as other meters.

author: AVGresponding
author_rank: Super Contributor
timestamp: May 15, 2025, 05:04:24 pm
content: Quote from: BeBuLamar on May 15, 2025, 11:55:23 amThat's not how my 289 worksMaybe the one/s you used were faulty?

author: BeBuLamar
author_rank: Super Contributor
timestamp: May 15, 2025, 08:48:12 pm
content: Quote from: AVGresponding on May 15, 2025, 05:04:24 pmFaulty?? I have use several 289 and 287 they all have the same problems. Very poor display contrast. The back light is needed almost all the time. All of them were bought new and I have used them when they were new.

author: AVGresponding
author_rank: Super Contributor
timestamp: May 16, 2025, 05:05:58 am
content: Quote from: BeBuLamar on May 15, 2025, 08:48:12 pmMust be ambient conditions then. Never had a problem reading the display on mine.

author: J-R
author_rank: Super Contributor
timestamp: May 16, 2025, 06:29:16 am
content: I'm also happy with the contrast on my 287, purchased late 2019.

author: gabiz_ro
author_rank: Regular Contributor
timestamp: May 16, 2025, 01:44:18 pm
content: you will get a more darker background.Take an polarizer film big enough to fit lcd in any orientation,add it to lcd and rotate it until you get a better or needed contrast, mark position angle or lcd shape cut film and apply to lcd.For lighter background you may do all this steps after removing original film polarizer of lcd, as result you'll have only one polarizer on lcd not two.Is a little risky and require attention doing this, you may try first on broken lcd to see how is done, some heat and IPA will help removing and cleaning film and adhesive.

author: Wrenches of Death
author_rank: Regular Contributor
timestamp: May 16, 2025, 03:38:11 pm
content: Quote from: HP45man on May 15, 2025, 04:02:29 amI wonder if it would still occur if REAL solder was used to tin it?I don't use "lead free solder" for anything. It's worse than useless.WoD

author: BeBuLamar
author_rank: Super Contributor
timestamp: May 16, 2025, 05:00:09 pm
content: Quote from: J-R on May 16, 2025, 06:29:16 amI have a 289 purchased in 2017 and a 287 that was made in 2022 and both display are the same. Very low in contrast. I also used serveral others 289 and 287 that were issued to my co-workers they are all the same.

author: opablo
author_rank: Regular Contributor
timestamp: May 17, 2025, 05:23:19 am
content: I noticed that many people don't know exactly what do we mean by bad contrastSo a video is worth a million words... here's a simple comparative demo of multiple angles and multiple lighting conditionshttps://youtu.be/ErcP3l3svmkI'm not an EE; just a hobbyist... my feeling is that this is not a bad lcd hardware; but a bad lcd contrast (Vo) resistor v-divider design(I don't know how to word this properly; but I'm sure you will understand me)So it's a perfect opportunity for a quick mod replacing whatever resistor is defining this contraste for a more appropriate value

author: AVGresponding
author_rank: Super Contributor
timestamp: May 17, 2025, 06:24:18 am
content: I fail to see what the problem isOther than the silly Australian website being upside down. All the electrons will fall out!