Products > Test Equipment
Fluke 8840/42 Series Universal Replacement Display
(1/5) > >>
Kjo:
Rather than hijacking the thread "Fluke 8840A/AF 8842A VFD Display Replacement" I am starting a new one to outline my work in creating a 256x64 pixel graphics display to replace the VFD in Fluke 8840A/AF & 8842A multimeters. I have posted some of the basic work on the Fluke group over @ groups.io. But there is a lot of interest here and seemingly little crossover. 

A quick caveat on both this thread work and that of the referenced thread. There is a very well made blue LED replacement module made by a group in the Ukraine in eastern Europe. It directly replaces the VFD on the PCB and is powered from the Fluke 5VDC test point. I bought 4 of them to repair several meters immediately. They are quite nice except for a few issues I will point out. The blue color shows through the Fluke smoked bezel better than a brand new VFD (I have one). If you look close at the picture you will see that the annunciation glyphs are considerably smaller than on the original VFD. It is a flaw that should be correctable, but I dont know the restrictions the designers were faced with. At ~$35USD & $5USD shipping you cant go wrong.




It is a pain to remove an old VFD. Use lots of liquid or paste flux so as not to burn the pads or PCB. Suck out ALL the solder with a sucker or wick. Work from both sides. Once the old leads are loose, you have to carefully cut through the old mounting pads (4) with a box cutter, then clean the PCB. Nothing stronger than IPA or GooGone or you may damage the button conductive points. Then just follow the supplied assembly instructions.

KO3Y
lowimpedance:
If you head over to the buy/sell board the designer of this display replacement has a thread which should give you more detail etc.

https://www.eevblog.com/forum/buysellwanted/ebay-led-display-module-fluke-8840a42a-(diy-kit)-replace-broken-damaged-vfd/
Kjo:
If you just want a quick display fix, get the blue LED replacement. If you want to have some fun with a flexible graphics replacement (at a higher cost in time and money) read on.

I like building stuff with mono & RGB graphics displays. I have used several based on the ST7735 type controller. While not simple to use, the displays using this controller have directly addressable RGB pixels. This makes writing code using bitmapped font tables rather straight forward. However, I found no such displays that came near fitting the Fluke 884X front panel format. The Fluke requires a 4:1 display ratio to get all the information contained in the original VFD. However there are several OLED monochrome displays available in the $30USD range with a 4:1 ratio having 256 x 64 pixels with 16 gray-scale levels. These come in green, blue, yellow & white. (No red that I have found.) I'll jump to the punch-line and show the completed display. Then cover the development.

The following image shows the closest I could get to duplicating the Fluke 884X VFD and take advantage of the flexibility of a dynamic graphics display.



more to come - KO3Y
james_s:
I actually think the LED replacement looks better, it's much sharper and a nicer color though I do wonder why the glyphs are smaller than the original display, it seems like they could be made in arbitrary sizes. Neat project just the same though.
TheBay:
Neat project, but an OLED display has a shorter lifespan (And burn in problems) than the original VFD which sort of defeats the point compared to the current LED kit?
Navigation
Message Index
Next page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod