Fluke 83/85 and 87 lcd displays are not interchangeable

[ogdento]

TLDR:  an 83/85 (v1 or v3) display will NOT work in an 87, and an 87 (v1 or v3) display will NOT work on an 83/85.

I was testing a "broken" fluke 87 v1 meter and discovered that it was actually fine, but just had an 83/85 v1 lcd in it... 

I always thought the 80 series displays were interchangeable (with the exception of the 88 and 5/V series)...  I recall various forum posts suggesting that while the 83/85 display didn't have a "duty" indicator (which isn't used anyway) and had more bar graph segments, it would - or should - work in an 87.  However, it absolutely will not!

The displays look almost the same:


Even though the 83/85 and 87 displays look nearly identical, Fluke used a completely different column and segment layout on the two displays... which is why the display was garbled when I turned my 87 to Ohms, using an 83/85 lcd.  It should show "Auto", "0.L", "M" ohms, "40" range, and illuminate entire bar graph... but instead shows this:



A look at the service manual shows S0-S31 (and H1-4) control entirely different segments on the two LCDs.  About the only common ones are "AC", "DC" and a few bar graph bits.  I've attached snips of both:

The 83/85 v1 display (fluke # 782763, manuf # LS393C):


The 87 v1 display (fluke # 832188, manuf # LS394E):


So for example, "Auto" is controlled by S17 on the 87, but it's S16 on the 83/85 (and the columns H1-4 are flipped too)... so with an 83/85 lcd in an 87, we get the right bar graph arrow instead of Auto.

An 87 display is the only LCD that will work in an 87, and an 83/85 display is the only LCD that will work in an 83/85.  In both cases, a v1 or v3 LCD can be used on a v1 or v3 meter of the same number (83/85 or 87)... so in that respect the ONLY interchangeability is with the revisions.

[mzacharias]

I used an 83III LCD for an 83 Series 1. Works fine and has larger digits.

It did not work in an 87 but I suspect an 87III LCD would be backwards compatible with an original 87.

[Mortymore]

... but I suspect an 87III LCD would be backwards compatible with an original 87.

Yes it is.
I have one 83 with the LCD from a 83III and one 87 with the LCD from a 87III

[ogdento]

Yep, Mortymore and Mzacharias... that's absolutely what I was saying... the ONLY ones that work are the 1 or 3 version in the same model number, so an 87 3 display works with an 87 1 and vice versa (same with an 83/85).  I too have an 87 1 with an 87 3 display, and the 83/85 1 lcd works fine in my 83-3