Author Topic: EEVblog #1192 - Power Meter LCD Repair  (Read 1153 times)

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Online EEVblog

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EEVblog #1192 - Power Meter LCD Repair
« on: March 20, 2019, 09:44:47 am »
Repairing the faulty LCD in the Voltech PM300 power meter.

 

Offline Chipguy

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #1 on: March 20, 2019, 09:59:47 am »
Hi Dave

I 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Only problem today is: That Toshiba Controller is obsolete, but there is a replacement called RA6963 for it now.
« Last Edit: March 20, 2019, 10:15:55 am by Chipguy »
Where is that smoke coming from?
 

Offline chickenHeadKnob

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #2 on: March 20, 2019, 10:19:59 am »
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.
 
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Offline johnlsenchak

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #3 on: March 20, 2019, 10:44:17 am »


Damn  those  "Wu  Wu"   flat  flex  cables  made in  China  :=\
John Senchak "Daytona  Beach  Florida "
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https://www.facebook.com/john.senchak.1
 

Online EEVblog

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #4 on: March 20, 2019, 10:46:27 am »
I 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.

I suspect it won't last long too.
Yes, LS24060 display

 

Online EEVblog

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #5 on: March 20, 2019, 10:47:28 am »
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.


I thought that too. But further playing around (some off-camera) showed it was almost certainly the PCB interface
 

Online EEVblog

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #6 on: March 20, 2019, 10:50:30 am »
The best solution is to replace it with a Winstar WG24064 Display or a compatible display from Bolimyn will work also.

I see Newhaven have one, wonder if it's compatible?
EDIT: Looks like it, uses the RA6963 controller like the Winstar one
https://au.mouser.com/ProductDetail/Newhaven-Display/NHD-24064CZ-FSW-GBW

EDIT2: Nope, too small, this one is the right size:
https://www.newhavendisplay.com/nhd24064wgatfhvz-p-2073.html

And Crystalfonz too https://www.crystalfontz.com/product/cfag24064ayyhtz-240x64-lcd-module-graphical

I wouldn't mind a brighter and more readable display actually.
« Last Edit: March 20, 2019, 10:57:25 am by EEVblog »
 

Offline orion242

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #7 on: March 20, 2019, 12:41:51 pm »
I wouldn't mind a brighter and more readable display actually.

Can't blame you there.  Have 3x PM100s and the display is crap on all.
 

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #8 on: March 20, 2019, 02:43:09 pm »
I wouldn't mind a brighter and more readable display actually.
Can't blame you there.  Have 3x PM100s and the display is crap on all.

Digikey have them in stock for US$55 either yellow or blue

https://www.digikey.com/product-detail/en/newhaven-display-intl/NHD-24064WG-ATMI-VZ/NHD-24064WG-ATMI-VZ-ND/1885702
https://www.digikey.com/product-detail/en/newhaven-display-intl/NHD-24064WG-AYYH-VZ/NHD-24064WG-AYYH-VZ-ND/1701290

I like the look of the yellow one.
The white one seems out of stock everywhere.
 

Offline TheSteve

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #9 on: March 20, 2019, 03:46:39 pm »
Everyone enjoys a good LCD upgrade video.
VE7FM
 

Offline Chipguy

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #10 on: March 20, 2019, 05:05:34 pm »
The best solution is to replace it with a Winstar WG24064 Display or a compatible display from Bolimyn will work also.

EDIT2: Nope, too small, this one is the right size:
https://www.newhavendisplay.com/nhd24064wgatfhvz-p-2073.html

And Crystalfonz too https://www.crystalfontz.com/product/cfag24064ayyhtz-240x64-lcd-module-graphical

I wouldn't mind a brighter and more readable display actually.
The 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.
Where is that smoke coming from?
 

Offline Chipguy

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #11 on: March 20, 2019, 05:15:41 pm »
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.
Where is that smoke coming from?
 

Offline capt bullshot

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #12 on: March 20, 2019, 05:21:09 pm »
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/#msg1511569

Anyway, "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.
« Last Edit: March 20, 2019, 05:22:52 pm by capt bullshot »
Safety devices hinder evolution
 

Offline Chipguy

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Re: EEVblog #1192 - Power Meter LCD Repair
« Reply #13 on: March 20, 2019, 05:23:49 pm »
https://www.digikey.com/product-detail/en/newhaven-display-intl/NHD-24064WG-AYYH-VZ/NHD-24064WG-AYYH-VZ-ND/1701290

I like the look of the yellow one.

Oh that yellow one looks nice. It's only STN so the photo is a bit deceiving I guess.
Where is that smoke coming from?
 


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