EEVblog #1192 - Power Meter LCD Repair - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: March 19, 2019, 10:44:47 pm
content: Repairing the faulty LCD in the Voltech PM300 power meter.

author: Chipguy
author_rank: Unknown
timestamp: March 19, 2019, 10:59:47 pm
content: Hi DaveI lost count how many of exactly these Varitronix Displays I have replaced. This one will work for a few month and then fail again.I assume it is the MGLS-24064-x-x display.Yours is from 2002 and has actually lasted very long for that particular type. This display in a hand held device does not live beyond 5 years without losling lines.The best solution is to replace it with a Winstar WG24064 Display or a compatible display from Bolimyn will work also.They don't use hot bar anymore and made the zebras are a bit longer to accomodate 16 more contacts on each side for the lines, clever interleaved.Only problem today is: That Toshiba Controller is obsolete, but there is a replacement called RA6963 for it now.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: March 19, 2019, 11:19:59 pm
content: I am not entirely convinced that the problem was down on the PCB end. Reviewing the footage @ 9:00 - 9:06 it is possible forcing the ribbon into the glass interface re-triggered the failure, not sure. Delicate and dicky, the worst kind of connector. Its like a high maintenance girlfriend.

author: johnlsenchak
author_rank: Frequent Contributor
timestamp: March 19, 2019, 11:44:17 pm
content: Damn those "Wu Wu" flat flex cables made in China

author: EEVblog
author_rank: Unknown
timestamp: March 19, 2019, 11:46:27 pm
content: Quote from: Chipguy on March 19, 2019, 10:59:47 pmI suspect it won't last long too.Yes, LS24060 display

author: EEVblog
author_rank: Unknown
timestamp: March 19, 2019, 11:47:28 pm
content: Quote from: chickenHeadKnob on March 19, 2019, 11:19:59 pmI thought that too. But further playing around (some off-camera) showed it was almost certainly the PCB interface

author: EEVblog
author_rank: Unknown
timestamp: March 19, 2019, 11:50:30 pm
content: Quote from: Chipguy on March 19, 2019, 10:59:47 pmI see Newhaven have one, wonder if it's compatible?EDIT: Looks like it, uses the RA6963 controller like the Winstar onehttps://au.mouser.com/ProductDetail/Newhaven-Display/NHD-24064CZ-FSW-GBWEDIT2: Nope, too small, this one is the right size:https://www.newhavendisplay.com/nhd24064wgatfhvz-p-2073.htmlAnd Crystalfonz toohttps://www.crystalfontz.com/product/cfag24064ayyhtz-240x64-lcd-module-graphicalI wouldn't mind a brighter and more readable display actually.

author: orion242
author_rank: Unknown
timestamp: March 20, 2019, 01:41:51 am
content: Quote from: EEVblog on March 19, 2019, 11:50:30 pmCan't blame you there. Have 3x PM100s and the display is crap on all.

author: EEVblog
author_rank: Unknown
timestamp: March 20, 2019, 03:43:09 am
content: Quote from: orion242 on March 20, 2019, 01:41:51 amDigikey have them in stock for US$55 either yellow or bluehttps://www.digikey.com/product-detail/en/newhaven-display-intl/NHD-24064WG-ATMI-VZ/NHD-24064WG-ATMI-VZ-ND/1885702https://www.digikey.com/product-detail/en/newhaven-display-intl/NHD-24064WG-AYYH-VZ/NHD-24064WG-AYYH-VZ-ND/1701290I like the look of the yellow one.The white one seems out of stock everywhere.

author: TheSteve
author_rank: Unknown
timestamp: March 20, 2019, 04:46:39 am
content: Everyone enjoys a good LCD upgrade video.

author: Chipguy
author_rank: Unknown
timestamp: March 20, 2019, 06:05:34 am
content: Quote from: EEVblog on March 19, 2019, 11:50:30 pmThe newhaven display looks good. The bezel size is only 154mm wide so it should fit. Other displays have 164mm wide bezels. However the wider bezels are the ones that definetly have the lines on the zebra strip. That Crystalfonz display also looks good on the first glance. Good find.

author: Chipguy
author_rank: Unknown
timestamp: March 20, 2019, 06:15:41 am
content: Attached is an image that shows the failure mode of a Winstar WG24064 display. Around 2% of what we delivered failed like this.The rest of the display is unaffected and the dark patch grows bigger over the years.The supplier claimed it was a microfracture in the glass but on closer inspection on the microscope I never found any.It may be an issue with contamination of some sort.

author: capt bullshot
author_rank: Super Contributor
timestamp: March 20, 2019, 06:21:09 am
content: Dave:It's not the same issue, but you've asked for a more clear and sharp display:I've replaced the fubar LCD of this one by a modern TFT one:https://www.eevblog.com/forum/repair/tek-1502b-tdr-restoration-project-and-more/msg1511569/#msg1511569Anyway, "thermal repair" of these heat sealed film connectors does sometimes work, and sometimes not. Same for the zebras, cleaning and re-seating helps or doesn't.Chipguy:I've also seen this failure mode, but can't remember what unit it was.

author: Chipguy
author_rank: Unknown
timestamp: March 20, 2019, 06:23:49 am
content: Quote from: EEVblog on March 20, 2019, 03:43:09 amOh that yellow one looks nice. It's only STN so the photo is a bit deceiving I guess.