Fluke 12E "easter eggs"

[meeder]

AvE has been poking around a Chinese Fluke 12E and found out that it has some hidden features. Temperature and frequency/duty cycle measurements are available but it just hasn't got the buttons and the dial doesn't have the indent at the right spot for the temperature measurement.

https://youtu.be/FUmbsBYVTQ0

[TheAmmoniacal]

Why is this posted in Metrology?

Good find by AvE.

[meeder]

Sorry my bad, wrong part of the forum. Can a mod move the thread please?

[EEVblog]

Nothing new here. The original Fluke 75 could be hacked into the 77 by moving one jumper link.

[TheAmmoniacal]

Yep, definitely not surprising. But had not really occurred to me to check.

[EEVblog]

I hadn't heard of the 12E

[Jasper]

If you can believe the dates in the manuals, the 15B/17B are from 2002, the 12E is from 2008 (and according to fluke's Chinese website, it's for Education), and the 15/17/18B+ models are from 2014. They all look extremely similar on the outside, but the 12E innards in that video definitely don't look like the innards of my 15B do.

I would wild-ass-guess that they redesigned the whole range in 2008 but didn't start actually making the more upmarket models to the new design in 2014, if it turns out that the + models have a common chassis to the 12.

[mape]

I bought the 15b+ version (~$80) and now as I have looked images of 12b+ it seems to have exactly the same outfit and pcb. As I saw that AvE video I immediately modified my own meter to enable the thermal selection. (a little bit of carving the plastic) However It only shows '- 0L' on the screen no matter what you do.

So I started to compare the pcb with images of 17b+ pcb to see if there is some difference between them and yes there is. Both 12b+ and 15b+ are missing one chip on top right corner of pcb on main chip side. What I found out it seems to be EEPROM chip so most likely it is used to store the lookup table for mapping thermal element measurements to temperatures. So there is no free temperature feature on these models.

There is also missing some parts on low left corner from main chip. (most likely transistor and couple of resistors) Those are connected to over voltage led. So to get that working you should add those components.

And Another missing part is one trimmer just next to negative power pad. And it is wired to near the missing EEPROM. So most likely it is somehow related to temperature measuring.

Otherwise those other functions should be working if you could only make buttons to press them. I have not yet found any cheap buttons that would suit.

But If you really want those features I think that you should just buy the 17b+ as it cost something like $20 more than 15b+.

[Fungus]

I bought the 15b+ version (~$80) and now as I have looked images of 12b+ it seems to have exactly the same outfit and pcb. As I saw that AvE video I immediately modified my own meter to enable the thermal selection. (a little bit of carving the plastic) However It only shows '- 0L' on the screen no matter what you do.

It may be the same PCB but that doesn't mean it has all the components on it.

So I started to compare the pcb with images of 17b+ pcb to see if there is some difference between them and yes there is. Both 12b+ and 15b+ are missing one chip on top right corner of pcb on main chip side.

There is also missing some parts on low left corner from main chip. (most likely transistor and couple of resistors) Those are connected to over voltage led. So to get that working you should add those components.

And Another missing part is one trimmer just next to negative power pad. And it is wired to near the missing EEPROM. So most likely it is somehow related to temperature measuring.

See! 

As Dave would say: "It's a trap for young players..."

(hope the hole you made in your case isn't too big...)

[mape]

I did not yet made any holes in the cover. I only moved the end-stop point so that it was able to turn that temperature position.

The extra buttons would be great that I could get those software features working with chasing on Maybe I could find some old calculator with rubber buttons what I could extend with 3d printed parts. As I do no think that I am able to find correct size 12X6mm buttons, with enough height.

[2x2l]

I bought the 15b+ version (~$80) and now as I have looked images of 12b+ it seems to have exactly the same outfit and pcb. As I saw that AvE video I immediately modified my own meter to enable the thermal selection. (a little bit of carving the plastic) However It only shows '- 0L' on the screen no matter what you do.

So I started to compare the pcb with images of 17b+ pcb to see if there is some difference between them and yes there is. Both 12b+ and 15b+ are missing one chip on top right corner of pcb on main chip side. What I found out it seems to be EEPROM chip so most likely it is used to store the lookup table for mapping thermal element measurements to temperatures. So there is no free temperature feature on these models.

There is also missing some parts on low left corner from main chip. (most likely transistor and couple of resistors) Those are connected to over voltage led. So to get that working you should add those components.

And Another missing part is one trimmer just next to negative power pad. And it is wired to near the missing EEPROM. So most likely it is somehow related to temperature measuring.

Otherwise those other functions should be working if you could only make buttons to press them. I have not yet found any cheap buttons that would suit.

But If you really want those features I think that you should just buy the 17b+ as it cost something like $20 more than 15b+.

So the 17b+ is the 'best buy' for a "i dont want to take my 87v to this" but "i might need more than a 114"?

 it seems like unlike the 18b+, you get duty cycle, temperature (not sure if theres a k probe or what), and all that jazz. the only thing the 114,5,7's have over it is low-Z which can be useful hmm

[Fungus]

So the 17b+ is the 'best buy' for a "i dont want to take my 87v to this" but "i might need more than a 114"?

Only if you insist on multimeters that come in yellow rubber shoes.

it seems like unlike the 18b+, you get duty cycle, temperature (not sure if theres a k probe or what), and all that jazz. the only thing the 114,5,7's have over it is low-Z which can be useful hmm

Yes, the 17B+ has a lot more buttons and temperature is probably more useful then an LED tester. It's a solid choice for a general purpose multimeter.