New tool to find short capacitors on motherboards : shorty with display
 

Hi everyone,

I would like to share a project I made recently : I adapted a shorty device and added a display.
it becomes a 0.1mΩ meter with surprising stability.
the original shorty project is here : https://hackaday.io/project/3635-sho...circuit-finder
I did one showed here (http://kripton2035.free.fr/Projects/proj-shorty.html) and was pleased with its performances, but it lack a display.

here is a video showing the measuring of some small values resistors :
https://youtu.be/4F6QNSpWTos


here another video showing continuous resistance measuring along a soldier roller :
https://youtu.be/8mYyr9uKpFU


and last another video showing how to find a shorted capacitor on a 820-00165 macbook air motherboard.
fast and easy.
https://youtu.be/L4V3BWReZLY


I'm cleaning the schematic and sources, and will share it when it's ready.

Re: New tool to find short capacitors on motherboards : shorty with display
 

interesting, what is the avr adc resolution, 12bit?

Re: New tool to find short capacitors on motherboards : shorty with display
 

What micro controller did you

Could you please post the code that you used for this project

Thanks for posting this

Re: New tool to find short capacitors on motherboards : shorty with display
 

Nice work adding the screen, I look forward to you releasing the source and schematics.

Re: New tool to find short capacitors on motherboards : shorty with display
 

the microcontroller is an arduino nano
the ADC is an mcp3421 in 16 bits mode, the 18bits being too slow at 3 samples/sec

I first used the avr adc (at 10 bits) and it was enough with the shorty initial amplification (x200)
then I tried the 18b adc and lowered the amplification for better range to 27x
the video use the 18b adc in 16b mode (and no pga gain)
it can read 0.1mΩ to around 2.5Ω

Re: New tool to find short capacitors on motherboards : shorty with display
 

Thanks for posting.
I'm following your project with interest on eevblog too :)

https://www.eevblog.com/forum/testge...with-display)/

Re: New tool to find short capacitors on motherboards : shorty with display
 

Interesting project... :rejoice:

Re: New tool to find short capacitors on motherboards : shorty with display
 

very interesting project! thx for sharing!
we wait for details!:noob:

Re: New tool to find short capacitors on motherboards : shorty with display
 

share your schematic and code - dont take too long on board layouts - everybody will probably make changes anyway.
like ditching the arduino and putting an mcu on the main board.
personally i hate din connectors - that may just be me!
4mm shrouded sockets would allow me to just use my multimeter probes.

Re: New tool to find short capacitors on motherboards : shorty with display
 

It won`t be long before the chinese start selling it. Interesting project ,very good .

Re: New tool to find short capacitors on motherboards : shorty with display
 

you must have 4-wires probe or you won't get the reading stability like on the video.

Re: New tool to find short capacitors on motherboards : shorty with display
 

inside the shorty prototype

Re: New tool to find short capacitors on motherboards : shorty with display
 

Thought on that right after posting my comment :frown:
My advice, if any good, to is to hide something important and only release to forum registered members.
I'm sure anyone would come up with a better idea if @kripton2035 is up to it:wink:

Re: New tool to find short capacitors on motherboards : shorty with display
 

it is based on an open source design - it would be a bit wrong to close it.

on connectors - did i say i hate din plugs?
so for 4pins i would use mini-XLR connectors. :)

Re: New tool to find short capacitors on motherboards : shorty with display
 

just noticed, your prototype has an 8pin adc, but the part number your using is mostly just sold as 6pin sot23 package.

not a problem, but keep that in mind if your going to design pcb's

Re: New tool to find short capacitors on motherboards : shorty with display
 

the shorty original is open sourced, so I really can't make mine a closed design.
by the way, there is nothing complicated on this design, just add a display and a better adc on a shorty.
I even reused the same protoboard and box where my original shorty was.
I only was the first it seems to have this idea and realize it in real.

I will publish the design on my web site in a few days, the pcb will come later after testing it.

@stj : the adc is on a 8 pins protoboard, but it is a 6 pins, the last two pins are not connected on the adapter sot23-6 to 8pdip.

Re: New tool to find short capacitors on motherboards : shorty with display
 

i didnt know sot23-6 fited on those soic boards.
that's good because i have a load of those adapters. :)

infact other than the adc i have it all.
arduino's, blue-pills, esp8266's, oleds - i keep lots of such stuff! :D

Re: New tool to find short capacitors on motherboards : shorty with display
 

I also changed the aop, from a mcp6041 to a ad8628
the mcp had too much voltage offset, and I losed a lot of low mΩ resolution with it
the ad8628 is perfect with 1µV offset.

not sure you also have the aop in your drawers ?

Re: New tool to find short capacitors on motherboards : shorty with display
 

i only have dac's :)

Re: New tool to find short capacitors on motherboards : shorty with display
 

ad8628 is just an op-amp??