GW Instek LCR-821 LCR Meter Display Issue.......  - Page 1
Forum section: electronics / testgear

author: Smokey
author_rank: Super Contributor
timestamp: September 04, 2024, 10:38:57 pm
content: I scored a GW Instek LCR-821 LCR Meter from the ebays...Product page (discontinued) =https://www.gwinstek.com/en-US/products/detail/LCR-800DataSheet =https://www.gwinstek.com/en-global/products/downloadSeriesDownNew/13514/766Manual =https://www.gwinstek.com/en-US/products/downloadSeriesDownNew/13505/769...It appears to be working except for a few lines on the LCD display that are out:A quick teardown showed no obvious problems and reseating the display ribbon cables had no effect.The display itself is a pretty big big module with a sticker and the following part numbers:"13031101D129""LMBHAT014G18CS"Searching the last number turns up what looks like the same thing from an aliexpress seller for $62https://www.aliexpress.us/item/3256803247659429.htmlSo that's the story and the extent of the research I've done so far.What do you think? What would cause just a few lines like that to go out? Any hope of fixing this one, or should I just try the aliexpress replacement and see what if anything shows up in the mail?

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 04, 2024, 11:05:38 pm
content: The original LCD on the Hioki 3532-50 that I'm repairing also had a few lines missing, and a bad backlight. The easiest thing to do is to replace the LCD, assuming you get a good replacement.If the seller's feedback is good enough, it's probably worth a shot for $62 as long as they accept returns if it doesn't work.

author: nctnico
author_rank: Super Contributor
timestamp: September 04, 2024, 11:12:10 pm
content: It is possible there are a few bad solder joints on the display module's board (the row driver chips) or that the conductive rubber contact strips between the board and the screen itself are no longer making contact. What you can try is to take the display module apart and clean de PCB and conductive rubbers with alcohol. Just make sure to have room on a clean desk to lay out all the parts of the display.AFAIK this display module is pretty much self contained so any problem with the display module is most likely from the display module itself.

author: Smokey
author_rank: Super Contributor
timestamp: September 04, 2024, 11:19:19 pm
content: Quote from: nctnico on September 04, 2024, 11:12:10 pm...you ask a lot of this poor engineer....

author: Smokey
author_rank: Super Contributor
timestamp: September 04, 2024, 11:25:05 pm
content: wow. that was fast... Bing search already indexed this thread.. so my bing search for "LMBHAT014G18CS" points me back here as the top result...

author: Smokey
author_rank: Super Contributor
timestamp: September 04, 2024, 11:55:54 pm
content: PSA: Don't take apart a "LMBHAT014G18CS" display moduleWell that didn't go as planned. There is definitely a seriously high pin-count zebra strip along the top of the display... but..There is also this strange really thin cable on one side that appears to have been bonded to a row of pads on the display board.... I'm pretty sure this isn't going back together...I'm actually not sure how they even assembled it since you sort of have to drop the board straight down to get the metal tabs to allign, but this cable would need to be folded over.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 05, 2024, 12:02:48 am
content: Quote from: Smokey on September 04, 2024, 11:55:54 pmThat's also my experience with repairing bad LCDs. 🤣Replacement is soooooooo much easier, as long as an equivalent product is available.

author: Smokey
author_rank: Super Contributor
timestamp: September 05, 2024, 12:09:18 am
content: ... I guess Icouldsolder about 1000 kynar wires between the cable and the board.. good thing I have a clean area of bench ready

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 05, 2024, 12:11:14 am
content: Start now, and you might be half done by the time the new LCD comes from China. 😉

author: Smokey
author_rank: Super Contributor
timestamp: September 05, 2024, 12:27:44 am
content: wow. I reassembled the display and it actually does something!unfortunately that something is having even more dead rows than it did when I startedI guess I'll take one more shot at aligning everything.

author: Smokey
author_rank: Super Contributor
timestamp: September 05, 2024, 01:03:31 am
content: ..well I'm not ahead.. but I'm not as far behind as I was a minute ago.More dead lines than when I started but not as many as the worst go.I'm pretty sure what I thought was "bonding" of some sort was actually just the traces from the flex ribbon that delaminated and stuck to the PCB. You can see through the transparent ribbon where the traces came off. Old and crusty.... Since the traces came off the flex ribbon there was nothing really to solder to even if I wanted to point to point repair it.So the moral of this story is, seriously don't take apart a "LMBHAT014G18CS".

author: Kean
author_rank: Unknown
timestamp: September 05, 2024, 02:53:52 am
content: According to Google (and Dublin Zoo):QuoteIt sounds like Zebra contact strips in LCD modules have a similar lifespan.I've found that cleaning them rarely helps, and lining them back up during reassembly can be super tricky.

author: Smokey
author_rank: Super Contributor
timestamp: September 05, 2024, 03:04:29 am
content: Quote from: Kean on September 05, 2024, 02:53:52 amJust have to wait for some scientist to genetically engineer their relatives back from extinction:https://en.wikipedia.org/wiki/Przewalski%27s_horseThe thing that's not working in this display is not the zebra strip. That looks fine. It's the strange ribbon cable like thing that's being used like a zebra strip. Why oh why not just two zebra strips? The world may never know.

author: Kean
author_rank: Unknown
timestamp: September 05, 2024, 03:13:21 am
content: Quote from: Smokey on September 05, 2024, 03:04:29 amAh yes, I think I know what you are talking about now. I recall seeing those thin flex ribbons in some LCD modules and cheap calculators.Buy a new (old stock) module and hope it works...

author: Smokey
author_rank: Super Contributor
timestamp: September 05, 2024, 03:18:45 am
content: I need an actual camera for my microscope.. Sorry for the crappy picture..You can see the real zebra strip on the top (that's fine), and the crappy delaminated ribbon cable on the right. The dark lines are actually the rubber showing through where traces used to be.

author: Smokey
author_rank: Super Contributor
timestamp: September 06, 2024, 07:06:56 am
content: Ha! The signal path was messing around with a very similar display module here. (Around 6 min)...https://youtu.be/kNnc-lDHtrM?si=mUysRavLZf0ge69I

author: Kean
author_rank: Unknown
timestamp: September 06, 2024, 07:47:08 am
content: Quote from: Smokey on September 06, 2024, 07:06:56 amWell that instills some hope in repairing it. I didn't think the conductive glue on the flex would respond to heating well enough to be effective.

author: Smokey
author_rank: Super Contributor
timestamp: September 06, 2024, 08:11:31 am
content: My display cable is fully detached through... Someone may or may not have um... gotten too aggressive during disassembly.I was hoping to just use the instrument through RS232 and not worry about the display but there is an amazingly bad level of support. The "official" windows app from GW Instek was last supported in windows Vista. Windows 10 refuses to even try to run it, even in compatibility mode. I installed it in an XP VM, but getting the USB->RS232 adapter through the VM wasn't working.There are also exactly zero SCPI drivers for python (or anything else) that I could find. I found one labview vi, but I don't have labview.So ya... The busted display is minimally functional still so I'm going to quit messing with it for now.

author: Kean
author_rank: Unknown
timestamp: September 06, 2024, 10:10:40 am
content: For reference, I did a little searching and the LMBHAT014G18CS is made by Nan Ya Plastics in Taiwan.Specs for LMBHAx014x16CS areGraphic LCD moduleMonochrome240 x 128 pixels170 x 102 x 14mm module dimensions128 x 74mm viewable areaRA6963L2NA controller (5V logic)CCFL backlightRequires negative bias voltageDownload of catalog including this module can be found at NPC Taiwan websitehttps://www.npc.com.tw/j2npc/enus/prod/Electronic/Liquid-Crystal-Display(LCD)/Liquid%20Crystal%20Display%20(%20Graphic%20module%20)I couldn't find a datasheet unfortunately, so hard to know exact specs and compatibility with similar options.In particular what the suffix "G18CS" relates to, but most likely backlight colour and connection type.

author: Smokey
author_rank: Super Contributor
timestamp: September 06, 2024, 10:13:46 am
content: Quote from: Kean on September 06, 2024, 10:10:40 amkiller. I'll check that out. Shahriar replaced the backlight with LEDs on his. Looked pretty straightforward, but he already had it apart.