Scopemeter 97 poor contrast - Page 1
Forum section: electronics / repair

author: Denis1024
author_rank: Newbie
timestamp: November 08, 2019, 02:49:14 pm
content: 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?ThanksDenis

author: rvalente
author_rank: Frequent Contributor
timestamp: November 08, 2019, 04:25:27 pm
content: 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.checkhttps://www.eevblog.com/forum/repair/fluke-744-display/

author: testpoint1
author_rank: Frequent Contributor
timestamp: November 12, 2019, 05:38:05 am
content: yes, very old, the plastic need to be replaced it.

author: george.b
author_rank: Frequent Contributor
timestamp: November 19, 2019, 12:13:33 pm
content: 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

author: pocal
author_rank: Newbie
timestamp: August 13, 2020, 10:16:24 pm
content: bonjour le mien est en panne je sais pas dans quel état est l’Écran, je cherche des infos sur l'alimentation,je n'ai pas de tension nulle part sauf sur le transfo ou j'ai 20 volt et le schéma de l'alimentation est mal détaillé , je trouve les éléments sur la sérigraphie, mais sur le schémaavez vous un schéma de l'alimentation détaillé? merci pour la réponse

author: rvalente
author_rank: Frequent Contributor
timestamp: August 13, 2020, 11:37:53 pm
content: Quote from: pocal on August 13, 2020, 10:16:24 pmAltought I speak french, thats a english language forum.Could you try better describing your troubleshooting?https://www.cl.cam.ac.uk/manuals/pm93_95_97_fluke_93_95_97.pdf

author: shakalnokturn
author_rank: Super Contributor
timestamp: August 14, 2020, 06:31:00 pm
content: Quote from: rvalente on August 13, 2020, 11:37:53 pmWould be worth the bother trying englische even the French is very average.

author: rvalente
author_rank: Frequent Contributor
timestamp: August 14, 2020, 09:24:19 pm
content: Quote from: shakalnokturn on August 14, 2020, 06:31:00 pmNice, how is your portuguese? Probably better than mine...

author: shakalnokturn
author_rank: Super Contributor
timestamp: August 14, 2020, 09:59:21 pm
content: No chance... I can hardly make any difference between Spanish and Portuguese.I do find the Brazilian easier on the ear than the Portuguese though.

author: KRISTOFFER
author_rank: Contributor
timestamp: October 07, 2022, 04:16:25 pm
content: I have a worse problem. I picked up a 99 mark II 100 Mhz model with a damaged LCD. When I fitted it with a spare LCD from a scrap identical model, all the black appears clear and vice versa. IE the display is a negative.?