Fluke 177 display brightness

• Fluke 177 display brightness
  Posted by andyB2022 on 01 Feb, 2022 15:16
• 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?
  

  ---

  

  
• #1 Reply
  Posted by andyB2022 on 01 Feb, 2022 15:38
• 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.
• #2 Reply
  Posted by Fungus on 01 Feb, 2022 15:38
• Maybe you can crack it open and swap the LEDs for some bright white ones.
  
• #3 Reply
  Posted by rvalente on 01 Feb, 2022 16:17
• 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.
• #4 Reply
  Posted by BeBuLamar on 01 Feb, 2022 16:21
• Newer Flukes have the blueist white back light. I prefer the green backlight of the older models.
• #5 Reply
  Posted by andyB2022 on 01 Feb, 2022 16:22
• Thanks for the tip with the green wavelength (510 nm). I still prefer white ones, will come here with pictures after I "mod" it.
• #6 Reply
  Posted by paulbt on 03 Feb, 2022 08:46
• 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.
• #7 Reply
  Posted by andyB2022 on 05 Feb, 2022 08:12
• 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!
• #8 Reply
  Posted by tooki on 05 Feb, 2022 13:26
• Quote from: andyB2022 on 01 Feb, 2022 16:22

  Thanks for the tip with the green wavelength (510 nm). I still prefer white ones, will come here with pictures after I "mod" it.
  

  Many 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.
• #9 Reply
  Posted by andyB2022 on 10 Feb, 2022 10:39
• 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?
• #10 Reply
  Posted by tooki on 12 Feb, 2022 23:03
• 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.