Modding Fluke 51 II thermometer for more features.

[TiN_]

Hello everybody.

I have Fluke 51 II thermometer, single-input one. Have some possibility and ideas how to improve it by modification to more expensive 54 II or 52 II two-channel model.

I need some help from community to accomplish this task.
Have disassembled mine 51 II (220$) and saw that everything inside, including keyboard and main PCB is EXACT same as in most advanced 54 II (370$) version. So Fluke just designed top model and then make lower-priced models by limiting features and not soldering extra passives on PCB for second thermocouple channel. Only the enclosure of meter is different (51 II have no two extra holes for second thermocouple and three buttons (two for logging features and one T1-T2 switch)), but that easily can be drilled to make use of that.

I can and already done back conversion of my 51 II to 54 II. It detects now as full-featured 54 II model, two inputs all extra stuff present in 54 II. But there is missing some passives on PCB, so I need somebody, who have 54 II or 53 II or at least 52 II thermometers, and can remove back cover of meter, and make high-resolution photos to see what lacks on PCB. Only removing back cover of case is needed, no deeper disasseble, so you dont risk anything.

Just unscrew 4 screws (two on top back, two inside bat section) and pull cover out. make photos and post here or send to me by PM.

As proof, that I'm not telling BS here, i show my 51 II model modified to 54 II.

PCB of Fluke 50 II series

top:



back:



Also changed backlight from green to white, so now it looks much better.

As far mod is VERY simple, so everybody who is able to do regular VR mods for videocards/motherboards can convert their nice 51 II flukes to most advanced 54 with two channels, fully featured.

Modded fluke 51 to 54 (you can see that by T1 T2 symbols, not present in original 51 II)



More thermocouples support



Interval feature absent in original 51 II



If help appear , i will post everything in details what to solder and how to mod thermometer.

[Expat GriZ]

Tin...Nice job man!!! Always enjoy your posts...if I was home would post the pics up. Looks great.

[s0lid]

Is there similiar mod for classical 51 ?
Looks like they share the same PCB with the old 52.

[TiN_]

s0lid

I don't have old 51, but my teammate have. So who knows what will I mod tomorrow

[G H Z]

I wanna do this, cool mod TiN

[TiN_]

So remove cover from yours 52/54/53 fluke and gimme photos

[Hondacity]

niceee

someone open their flukeeeee 52/54

[pogiman]

nice. As a EE myself, I like to see more of these types of mods.

[TiN_]

Gotcha some updated

Soldered Videobios from 7900GTX to my fluke 51-2 @ 54-2, added debug wires to USB-UART bridge, and tested link with PC





Some junk from bios chip read by fluke lol notice 6K+ memory cell number. Native Fluke 54 support only 500







Need depletion-type transistors to add second channel now Cant find where to buy them in my country.
It's label is DN2540 in SOT89 package

[TiN_]

2nd channel added :

[l0ud_sil3nc3]

very nice mod

[systemviper]

amazing, i am lovin it

[s0lid]

Have i yet mentioned that you're hw god?

[T_M]

So i presume you got the photos you needed?
If not i can take and send tonight

[hiwa]

great job Tin
did u get the pics from 52II? if not replay here i send you tonight.

[TiN_]

I have only 54 II photos now, but since it's top model, i think everything maxed out.

There is some minor issues left, but that's easy to fix, just need to get some cheapo parts.

I will update things bit later.

[hiwa]

here is 52II maybe u will need
let me know if u want better pic or any other info


Uploaded with ImageShack.us

http://img826.imageshack.us/img826/1866/img3026i.jpg

[TiN_]

Hm, interesting

Thanks for photo.



Second channel online....

Now I'm going to add two extra channels (to have overclocked FOUR-channel Fluke 54II). Or 58 II ? :-D

[hiwa]

lol nice one man show us 58II

[G H Z]

Can we get a quick run down how to perform this mod? I wanna do this really bad so I can throw away my UEI

[trans am]

Can we get a quick run down how to perform this mod? I wanna do this really bad so I can throw away my UEI

GHZ toss it out or use it to make sure your beer is the perfect temp before drinking. benchzoner turned me onto the fluke early this summer and my god what a difference. the uei was cool for when I started out on the dice benches but after the fluke its like night and day. not just the rapid temp refresh readings but the battery life is second to none. Do the batteries ever wear out on this thing?! Ive been through 6 long sessions on used AA batteries and the fluke is still ripping. I think it pays for itself just by that fact that you wont have to buy new 9v batteries every other session. I would definitely go this route for those on UEI or guys just getting into extreme cold. and now with this mod its a no brainer. If I didnt have the 52II already this is the way to go.

[Trouffman]

Is there a way for you that once you teste thte everything is working fien to make a somplete procedure article about how to mod it ? that's AWESOME man !

[TiN_]

Sure there will be complete and definitive guide, I just want to check everything. And videobios dont work nice in fluke as logging storage lol, different memchip adressing/capacity. GHZ i will post everything on our homeforum lol

I guess nobody needs logging/pc comms features, yes? I mean modding 51/52 into 53/54

I'll make two parts of guide. One for newbies, just add second channel, mod to 54 (to support more thermocouples and faster response time), backlight change. Just few passive SMDs needed for this mods (5 resistors and 2 capacitors), easy doable.

And extreme PURE part, where real man plays. Adding two more channels, logging features, USB link, extra color for backlight (to show which pair of channels monitored now, T1 T2 or T3 T4 (fluke firmware shows only two channels).).
This is going to be small DIY PCB with two chips and few passives hooked to fluke main PCA.

[CL3P20]

What PCB is safe from this man's creative lunacy? Great mod Tin.. could be a real money saver for the 'do-it-yourself-rs'

[TiN_]

Those which I can't afford are safe for now...