Author Topic: Scopemeter 97 poor contrast  (Read 416 times)

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Offline Denis1024

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Scopemeter 97 poor contrast
« on: November 08, 2019, 02:49:14 pm »
Hello,
I bought an old Fluke 97, but unfortunately it was down. I repaired it, one of the failures was the backlight. Now everything is fixed, but the LCD has a very poor contrast, at the limit, hard to read, even with a strong light or even with the backlight.

The pixels are not dark, but gray.
I wonder if such an LCD screen can be damaged for years?
Is there someone who owns a 97' with a good contrast?

I found this thread:
https://www.eevblog.com/forum/testgear/old-philips-fluke-97/100/

It seems that a polarizer can be damaged over the years?
Could someone confirm that?
Thanks
Denis
 

Offline rvalente

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Re: Scopemeter 97 poor contrast
« Reply #1 on: November 08, 2019, 04:25:27 pm »
Ive had this trouble with my ths720p, bad polarizer, had to replace it. The contrast is not the same as the genuine material from sharp but, is very useable.

You should post a picture but, if the screen is inverting colors from the center to the edges in a circular form, its very probable the polarizer ia bad.

check https://www.eevblog.com/forum/repair/fluke-744-display/
« Last Edit: November 09, 2019, 06:56:49 pm by rvalente »
 

Offline testpoint1

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Re: Scopemeter 97 poor contrast
« Reply #2 on: November 12, 2019, 05:38:05 am »
yes, very old, the plastic need to be replaced it.
 

Offline george.b

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Re: Scopemeter 97 poor contrast
« Reply #3 on: November 19, 2019, 12:13:33 pm »
Like rvalente said, bad polarizer. Extremely common in 90s LCDs.

I reuse polarizers from broken, modern LCD screens for repairing those with some success. The color is usually a bit off, but meh :-//
 
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