Poor Fluke 87V DMM LCD Segments Contrast - Page 1
Forum section: electronics / testgear

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 10, 2022, 02:40:22 pm
content: i noticed there's already a thread about thisPoor Fluke handheld DMM display anglesbut i want to make my own because this is my specific unit and the topic above is not really spot on... my unit is varying blackness across segments. those that should be ON (black) should be pure black, but some of them are just lightly grey. those that should be OFF (transparent or white) some of them are lightly greyed as well.. refer to attachment below...story: i just received it few minutes ago all the way from an ebay USA seller sent about a month ago. he claimed it as new (open box just to put lcd protector and for testing) Manufactured/Calibrated January 2022 but the certificate to prove this is not provided in the box (unlike some of the chinese instruments that i bought earlier) i'm not sure if this is typical for Fluke product, but i never had bad experience with USA sellers that usually underrated their products in ads so i always received more than happy experience, even for used products they sell. not this time, but i wont accuse this seller for cheating, i think the presence of previous thread indicates there is some quality issue with Fluke nowadays..until proven otherwise. this is a bit of disappointment because i have a used Gossen Metrahit XTra that has the most perfect pitch black uniform contrast LCD i've ever seen, and my 12yrs old Uni-T 71A is not as bad, not even close as this Fluke's "reject" LCD. i bought this Fluke just to add trustability to my measurement units and to verify the unknown state of my Gossen and the rest of my china DMMs.1s.jpg: non-uniformity in contrast can clearly be seen.2s.jpg: same thing, we can mistakenly read as 1.8 instead of 1.0.3s.jpg: same thing, need to carefully read by changing viewing angles to verify its 9.24 instead of 9.844s.jpg: V and dc are dimmed...5s.jpg: changing mode, the V got better (blacker) a bit, so this is not systemic for each segment, they can grow better (blacker) in time, or got worst in another mode6s.jpg: just how bad it is...battery is checked and switched with another battery to test (9-9.24V), so this is not battery weak scenario. appearance and smell is indeed like a new unit, with protective layer on LCD (i think it is from factory, not from seller, its cheap flexible plastic type). ebay seller the_e-recyclers with 5 figures rating with only a number of neutral/bad ratings, in case you know him. he offered the best price with new hard waterproof pelican case. functionalities seem fine so far, calibration state is yet to be discovered. i need to find where i've put my single chip reference voltage is... returning it i guess will not be beneficial in term of my cost and time, if it works fine i'll just have to deal with it. (edit: not a single viewing angle you can find a perfect view, all angles top bottom left right will show this imperfection with just some slight varying degree of contrast) FWIW...

author: Fungus
author_rank: Super Contributor
timestamp: May 10, 2022, 02:41:58 pm
content: Looks like it needs a clean of the zebra strips that connect the screen to the PCB.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 10, 2022, 02:46:53 pm
content: Quote from: Fungus on May 10, 2022, 02:41:58 pmthats what i'm afraid of for a new unit that needs zebra strip cleaning. that strip is kinda sensitive, wrong move and pressure during cleaning i can make it even worse. if you compare 5s and 6s, the leftmost zero is fine on 5s.jpg, but got worse in 6s. each segment sometime ok, sometime not ok. so i doubt it zebra strip connection.

author: TheBay
author_rank: Unknown
timestamp: May 10, 2022, 03:01:01 pm
content: It shouldn't be like this at all, I've got a few of these and yes older versions have different LCD displays with poor contrast.But not differences between digits. It really does look like a zebra strip issue or the PCB/LCD has a film of grease or something where the zebra strip makes contact.The question is, why is it like that as I can't see how it would have passed QC at Fluke, maybe things are a bit slack there since the pandemic I don't know, but immediately I'm wondering if someone has just fitted a new housing to an old meter or something?Is the serial number sticker on the back of the meter and does it match the serial number on the PCB?And these have that "Screen protector" applied by the factory.

author: Fungus
author_rank: Super Contributor
timestamp: May 10, 2022, 03:09:35 pm
content: Quote from: Mechatrommer on May 10, 2022, 02:46:53 pmNah, they're notthatsensitive, especially new ones (this one isn't 30 years old!). Try cleaning the PCB first then go for the strip if that doesn't work. Also try flipping them around to different orientations.Have you taken it apart yet? Open it up and press on the back of the screen housing.It could be a screw that isn't fully tightened to press the zebra strip against the screen, maybe even a missing screw.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 10, 2022, 03:16:21 pm
content: Quote from: TheBay on May 10, 2022, 03:01:01 pmfor this i have to open up the DMM and void the warranty... btw, i checked back the ebay ad, the seller claimed "the display itself is flawless" and his picture proved that (attached), the flaw was not there... i tend to believe its the same unit as what i've received since it had slanted protector layer on the LCD that i have to correct myself. so maybe the flaw occured during its journey on the way to my place here...edit later:Quote from: Fungus on May 10, 2022, 03:09:35 pmif i dont get a better solution from members within this few days, then maybe i'll have to implement this eevblog rule and forget about the warranty. i contacted the seller with link to this thread, let me see what his reply will be... this is not a cheap toy btw that i can buy as many as i want..

author: rsjsouza
author_rank: Super Contributor
timestamp: May 10, 2022, 03:51:40 pm
content: Mecha, this is not normal for an 87V - I know mine and several others at work that show very solid segments with no bleeding.That said, this is a problem on my 189 - it bleeds through segments and has some uneven contrast. I did it all: cleaned the Zebra strips, the PCB where the contacts are placed and even replaced the original pink strip with a cut-to-measure grey zebra strip bought online. Nothing changed, unfortunately.A short clip about it (in portuguese, sorry)

author: TheBay
author_rank: Unknown
timestamp: May 10, 2022, 04:01:16 pm
content: Quote from: Mechatrommer on May 10, 2022, 03:35:08 pmThat does look to be the same multimeter as "True RMS Multimeter" isn't printed correctly on both yours and the one from the advert.Is there some kind of warranty sticker or something on it? You didn't comment if it has a serial number sticker on the back of the unit.Fungus is right with what he said about the screws, the LCD/button housing is screwed to the PCB with 4 screws and if they are loose it can cause issues with the zebra strips not making contact properly.Also just had a thought, as well as the 4 screws the front "True RMS Multimeter" part is clipped on to the LCD/Button housing, this could have worked loose/come unclipped slightly due to shipping?

author: AVGresponding
author_rank: Super Contributor
timestamp: May 10, 2022, 04:08:16 pm
content: Have you removed the screen protector and re-applied it? If not, I highly doubt that it is the same meter; the alignment and pattern of air bubbles is completely different.Quote from: TheBay on May 10, 2022, 04:01:16 pmI'm slightly puzzled about what is wrong with it, as it appears the same as the lettering on the Fluke website.https://www.fluke.com/en-us/product/electrical-testing/digital-multimeters/fluke-87v

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 10, 2022, 04:27:21 pm
content: Quote from: TheBay on May 10, 2022, 04:01:16 pmif the protective layer is indeed from factory, thats a clear proof Fluke has some quality issue. the slanted layer is like someone asleep or having a flu doing the jobQuote from: TheBay on May 10, 2022, 04:01:16 pmit has just one small sticker at the back with numbers (attached below, i guess its the serial number, i just filled registration form of Fluke corp at my country) and nothing else not even "warranty void if broken" sticker. i expect it comes with a calibration certification though with date written on it, sadly its not... only the typical manual booklets.Quote from: TheBay on May 10, 2022, 04:01:16 pmi've made some zebra strips cleaning before, from cheap $0.1 strip that is once disassembled permanently damaged, to a quite good forgiving strips, i hope the Fluke used the later type...Quote from: AVGresponding on May 10, 2022, 04:08:16 pmyes i mentioned i have corrected the slanted layer before i snap those pictures, thats why you saw many bubbles in OP because my room is full or it (it actually dusts trapped just within 5 seconds i tried to reapply it, but i dont care, i can do better next time)... the layer initially exactly like in advert, heavy slanting, even a sloppy me will not do that.

author: bdunham7
author_rank: Super Contributor
timestamp: May 10, 2022, 04:31:01 pm
content: Quote from: Mechatrommer on May 10, 2022, 03:35:08 pmNot to be critical, but how much would this have cost to buy new from an authorized distributor in your location? Here, TEquipment has them with an i400 current clamp for $485 with free shipping and a 6% EEVBlog discount. I've seen this seller before and while I've no reason to think they are dishonest, I don't think they have any deals.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 10, 2022, 04:49:26 pm
content: Quote from: bdunham7 on May 10, 2022, 04:31:01 pmseller's price is 399.95. i paid 500 incl shipping and tax, and i got free pelican case. i dont think i have the luxury of free shipping from tequipment. if i have to buy local, its still oversea 2K+ km away, $100 more ($600+ total) and no case no i400. i thought, there should be no difference any Flukes will have to come from USA anyway... but i paid the price, the seller is half the globe away. if i buy local maybe i have the same problem, just a little bit easier for return and refund, things happened, unexpectedly.edit later:the seller replied, he also a fan of eevblog. looks like i have to do zebra cleaning... previous generation 87 its commonly happened, debris or spec residue, according to him. but V series, it only happened to me among many he sold, so... maybe tomorrow i'll do it when in peak health... i missed that the manufacturing date is on the side of the box, not on a cert. he told me that. the sn on the box is same as on the backof DMM, now i know. i'm going to reply to him again as to why he checked the LCD ok, but when arrived its not, if its due to debris, its must have been from factory and also when he tested it.. maybe one possibility is some vibrations made some strip connection loose on its way, maybe.

author: AVGresponding
author_rank: Super Contributor
timestamp: May 10, 2022, 05:19:54 pm
content: It's a strange one, I'd be strongly tempted to request an exchange unit, let the seller deal with Fluke directly, but given the time that would take, trying to clean the zebra strips first seems a reasonable step.

author: free_electron
author_rank: Super Contributor
timestamp: May 10, 2022, 05:23:58 pm
content: Quote from: rsjsouza on May 10, 2022, 03:51:40 pma strategically placed piece of foam in the top left corner ( when looking at the backside ) to press down on the pcb a bit got mine back into tiptop shape

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 10, 2022, 05:33:16 pm
content: Quote from: free_electron on May 10, 2022, 05:23:58 pmso its a tolerance or clearance defect then. i remember i did the same trick on a cheap unit i cant remember what, to fix it. if pressed harder, zebra strip will make better connection. what i really afraid of, if i accidently touched anything inside that will affect calibration. i fixed many things before, but they are all used or cheap items. its like the feeling when i fixed my Metrahit, i thought, the calibration is surely gone i think, the very reason why i purchased this Fluke.

author: TheBay
author_rank: Unknown
timestamp: May 10, 2022, 05:45:35 pm
content: Quote from: Mechatrommer on May 10, 2022, 05:33:16 pmIf you do open it, don't bother just yet cleaning the zebra's, just check first that the plastic LCD cover is clipped on correctly, this may have worked loose in shipping. You can see this part in this video by FlukeThen check the 4 screws are not loose on the back.You would not effect calibration even if you had to clean or replace the zebra's as they come out quite easily without taking the PCB off the plastic frame.

author: BeBuLamar
author_rank: Super Contributor
timestamp: May 10, 2022, 05:52:16 pm
content: I don't know about Malaysia but I believe Fluke would fix it for free under warranty.

author: rsjsouza
author_rank: Super Contributor
timestamp: May 10, 2022, 06:41:12 pm
content: Quote from: free_electron on May 10, 2022, 05:23:58 pmThanks Vincent. I have tried that as well, as my board is slightly U-shaped, but unfortunately it did not improve the situation.It occurred to me that perhaps the MCU/display driver pins might need cleaning. Next time I open the meter I'll investigate.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 10, 2022, 07:28:12 pm
content: Quote from: TheBay on May 10, 2022, 05:45:35 pmok guys i think i've fixed it. with materials and discussions here, you've put me into more confidence tonight. cleaned myself up and blow the dust off my bench to do the "easy" (i thought) fix. indeed its just an easy fix, but the thing is the other way around. the 4 screws at the back is already tight, pressing the PCB and LCD (frame) together did not fix it, but once i unclip the frame, the LCD is fixed right away! so i think something in the frame is pinching too much on the LCD, i saw some manufacturing bumps on it (can be seen in attachments 2nd and 3rd) so i'm filing those off, they are just mechanical parts. but even they are gone, putting back the frame still the same flaw, so i unlicp again, LCD ok again (if pressed properly), put it back again with carefull attention to the alignment, wiggling it a bit into place, and the LCD is now OK, putting them back together, and still ok! success guys! taking pictures of the PCB while on it before putting the enclosure back, for the record. i wont further dismantle the metal and plastics covering on the pcb, i dont want to get too much inside unecessarily risking the calibrated sections. so i wont bother to find the serial number inside, if its legit, because i think it is, from an honest seller, this is just an unfortunate occasion, its like embedded with me, its not legit if i dont fix anything!so, thanks all for your input.yeah i'm really in a pinch, sending it back, pay more shipping cost, wait another 1-3 months for another unit feel too much hassle. diy with courage from friends will only take minutes! i'm just a little bit late to bed tonight, but with relief... conclusion: imho its still manufacturing/tolerance defect from Flukes side, in this case i think too tight LCD frame, a slight bump may place the LCD into misalignment or pinching, not sure, but it responsible for the bleed i saw in OP.ps: i dont even want to lift the LCD up first to avoid risk of introducing more dusts into this $500 (zebra strip) instrument. if only i cannot fix the frame problem, then i have to open them up furthermore. rule #1... fix the easier and less risky part first!edit: other reference...

author: floobydust
author_rank: Super Contributor
timestamp: May 10, 2022, 08:21:07 pm
content: Good you got it fixed with minimum hassle. You used an Exacto knife to shave off the burrs?I'm not sure what you've got- but I do notice a drop in quality. The housing and injection moulding appears to be lower quality. The silkscreened text certainly is not what it used to be either."True RMS Multimeter" is crooked, the rotary switch is missing the white pointer, and the text looks washed out, compared to other 87V pics.Fortive sure has boneheads doing cost er profit improvement.

author: Mechatrommer
author_rank: Super Contributor
timestamp: May 10, 2022, 11:28:52 pm
content: Quote from: floobydust on May 10, 2022, 08:21:07 pmi tried using normal cutter/paper knife, its too thin to cut off, or my knife is not sharp enough. so i just use a cheap flat file from a set like this..as i mentioned, its not directly fix the problem, reseating the frame at correct position/alignment fixed the issue. maybe flattening the bump could help, but i'm not certain.edit later:cross link tomeasurement verification

author: mopplayer
author_rank: Contributor
timestamp: May 08, 2025, 05:44:26 am
content: Quote from: rsjsouza on May 10, 2022, 03:51:40 pmYou were not alone.The very old HP/YOKOGAWA meter was the same. After cleaning out, that LCD was leaking many segments obviously.After replacing the LCD of another meter, all other parts were fine, but I decided to leave the LCD alone, don't replace it.Because those meters are well worthy of a collection (from another perspective).