Fluke 177 display brightness - Page 1
Forum section: electronics / testgear

author: andyB2022
author_rank: Regular Contributor
timestamp: February 01, 2022, 03:16:15 pm
content: Hi, I've just got a Fluke 177. The thing that I don't like about is that the backlight is way too dim. Meters under 50$ beat the display luminosity by far. As I've seen there are models out there with nice and bright white backlight. Why did they put this rubbish green backlight?

author: andyB2022
author_rank: Regular Contributor
timestamp: February 01, 2022, 03:38:06 pm
content: Got this one from a guy for under 200$, it was never used, the display still has the protecting film on top.I don't know how old it is... Any way I can find out?Replacing the LEDs seems the best solution so far. It should be pretty easy to replace as they are on the main PCB.

author: Fungus
author_rank: Super Contributor
timestamp: February 01, 2022, 03:38:46 pm
content: Maybe you can crack it open and swap the LEDs for some bright white ones.

author: rvalente
author_rank: Frequent Contributor
timestamp: February 01, 2022, 04:17:42 pm
content: Measure the VF over the diodes, and trying swapping for low current pure green models.Why pure green? The human eye has the highest sensitivity on this wavelength.

author: BeBuLamar
author_rank: Super Contributor
timestamp: February 01, 2022, 04:21:48 pm
content: Newer Flukes have the blueist white back light. I prefer the green backlight of the older models.

author: andyB2022
author_rank: Regular Contributor
timestamp: February 01, 2022, 04:22:51 pm
content: Thanks for the tip with the green wavelength (510 nm). I still prefer white ones, will come here with pictures after I "mod" it.

author: paulbt
author_rank: Regular Contributor
timestamp: February 03, 2022, 08:46:48 am
content: Hello, andyb2022!Old Flukes have this green backlight which will fade over time depending on the battery voltage. Just replace it and see the difference. Newer Flukes same model have a cold white backlight which I think does not fade. By "new" or "old" I am referring to the manufacturing date.

author: andyB2022
author_rank: Regular Contributor
timestamp: February 05, 2022, 08:12:05 am
content: Multumesc de raspuns! Thanks for the reply! I don't have the tools and Led's in stock right now to replace them, I'll definitely take some pics with before and after!

author: tooki
author_rank: Super Contributor
timestamp: February 05, 2022, 01:26:21 pm
content: Quote from: andyB2022 on February 01, 2022, 04:22:51 pmMany white LEDs are extremely efficient, so will still be very bright.Bear in mind that both “pure green” and white LEDs have forward voltages much higher than traditional green LEDs (>3V, vs. 2.2V for traditional green), so it’s possible they won’t light up brightly without modifying the backlight circuit.

author: andyB2022
author_rank: Regular Contributor
timestamp: February 10, 2022, 10:39:36 am
content: It's done. I really like the way it looks now. Unfortunately I don't own a 2'nd meter with OEM white LED's to compare brightness and temperature color. Even though I think it's pretty close to an OEM one.Used LED's:https://www.tme.eu/Document/d26ce7498165dd111bacf44414ac0cf2/LL-S150W-W2-1B.pdf(I post images this way because after I upload the files here on the forum it just doesn't make the post. Anyone knows what am I doing wrong?

author: tooki
author_rank: Super Contributor
timestamp: February 12, 2022, 11:03:28 pm
content: Looks very similar to original Fluke white backlighting, nice job!Inline images are broken. But as attachments work fine, and that’s generally preferred as they won’t break later on, as external images often do.