Author Topic: finding short on motherboards with a shorty (with display)  (Read 10719 times)

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Offline kripton2035

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finding short on motherboards with a shorty (with display)
« on: February 03, 2021, 07:06:22 pm »
Hi everyone,
[attachimg=1]

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-shorty-short-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.
just teasing ;)

« Last Edit: February 03, 2021, 08:56:10 pm by kripton2035 »
 

Offline Fraser

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Re: finding short on motherboards with a shorty (with display)
« Reply #1 on: February 03, 2021, 07:41:15 pm »
Excellent. I look forward to reading more of this unit  :-+

Fraser
 

Offline zoltanh

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Re: finding short on motherboards with a shorty (with display)
« Reply #2 on: February 04, 2021, 12:04:02 am »
Super!!
I built myself a shorty (designed a board with arduino nano, THT and SMD versions, but built till now only THT version; SMD PCB is done but not populated) and did several experiments and several changes. The last version is up to 5 ohms instead of 1 ohm original. I made and tried also few sketches as I changed/experimented the approach how to translate the voltage readings in tones/sound. Actually, I am very pleased, with all versions, original and mine ones how they translated the milliohms in tones. I was thinking about adding a display, and adding voice talking. I started with voice talking implementation. Then I have seen few weeks ago, on other topic hereon the forum, your post about your shorty with display. Since then I put it in hold and I was waiting to see your realization. I hardly can wait to see your schematics and source if you would like to share.
 

Offline masterx81

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Re: finding short on motherboards with a shorty (with display)
« Reply #3 on: February 04, 2021, 09:08:16 am »
I love the sound frequency proportional to the resistance! And seem have quite stable reading. Really interested!
 

Offline kripton2035

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Re: finding short on motherboards with a shorty (with display)
« Reply #4 on: February 04, 2021, 11:17:13 am »
the good news is that inside the box everything is wired "bugstyle" on a perfboard... I will certainly make a good pcb with groundplanes...
and add one more digit to the display !
 
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Offline natman69

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Re: finding short on motherboards with a shorty (with display)
« Reply #5 on: February 06, 2021, 05:21:59 pm »
@kripton2035: really an interesting project. This tool can be very useful. Great! And thank you for sharing...

If there is enough interest about eevblog users, I suggest you to sell a PCB or a complete kit for building shorty.
 

Offline Fraser

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Re: finding short on motherboards with a shorty (with display)
« Reply #6 on: February 06, 2021, 05:27:55 pm »
+1 for a Shorty kit  :-+

Fraser
 

Offline Johnny10

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Re: finding short on motherboards with a shorty (with display)
« Reply #7 on: February 06, 2021, 05:31:32 pm »
Yes,  :-+ would make a great kit!
Tektronix TDS7104, DMM4050, HP 3561A, HP 35665, Tek 2465A, HP8903B, DSA602A, Tek 7854, 7834, HP3457A, Tek 575, 576, 577 Curve Tracers, Datron 4000, Datron 4000A, DOS4EVER uTracer, HP5335A, EIP534B 20GHz Frequency Counter, TrueTime Rubidium, Sencore LC102, Tek TG506, TG501, SG503, HP 8568B
 

Offline kripton2035

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Re: finding short on motherboards with a shorty (with display)
« Reply #8 on: February 08, 2021, 05:32:11 pm »
here are some picture of the shorty with display, external and internal.
 
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Offline zoltanh

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Re: finding short on motherboards with a shorty (with display)
« Reply #9 on: February 09, 2021, 06:18:59 pm »
I hope it is fine adding something to the subject. If it is not, I apologize.
This is my shorty. I altered the schematics and use MCP601 at voltage supply of 5v, and Arduino Nano. I setup the current level for measurements at 25.5 mA, and gain of op-amp at 27.45. I have attached a picture of PCBA (THT) with LCD (I2C) not attached to it and SMD PCB on which I plan to change supply voltage at 3.3V using 3 diodes in series.
I am impressed by this device's performance and stability at 2 milliohms resolution. It produce audible differences at changes of few milliohms and together with display and a LED I added, which is in synchronism with the buzzer, it is very nice tool to work with. I did not use 4 wires connections as I subtracted the resistance value of wires into calculations. At the end for locating a short circuit I like mostly it to be setup for a range up to 1.5 ohms. I checked this simple construction against an industrial milliohm meter in measurements and I am impressed by its performance, not speaking about visual and audio aid it brings with.
Below I included one of sketches just as an example how simple it is, in my case. It does not include LCD subroutine. I list below the code as it is short.

//by Zoli on Jan 2021

const byte sensorPin = A5;    // select the input pin for sensor
int buzzer = 6;//audio output
int led = 13; //signal led
long sensorValue = 0;  // variable to store the value coming from the sensor
int pnp = A3; //transistor base
float voltage;
float voltagei;
float ohm;
int j;


void setup() {
  Serial.begin(9600);
  analogReference(INTERNAL);//using internal 1100mV reference
  pinMode(sensorPin, INPUT);
  pinMode(buzzer, OUTPUT);
  pinMode(pnp, OUTPUT);
  pinMode(led, OUTPUT);
 
  }
 
 
void loop() {
  digitalWrite(pnp,LOW);
   digitalWrite(led, HIGH);
  for (int i=0; i < 20; i++) {
sensorValue = sensorValue + analogRead(sensorPin);
 }
 sensorValue =sensorValue/20;
 

    voltage = ((sensorValue * 1100)/1024 );
    voltagei = voltage / 27.45;
    ohm = ( voltagei/25.5) - 0.05;

   
  // print out the value you read:
 Serial.println(ohm,5);
  //Serial.println(voltage , 5);
 //Serial.println(voltagei , 5);
 //Serial.println(sensorValue);
 
 delay (2);
 if (ohm <1.5){

  // change the analog out value:
 
 digitalWrite(buzzer, HIGH);
 analogWrite(6,( 4500*ohm));
 digitalWrite(led, LOW);
 
  // stop the program for <sensorValue> milliseconds:
j = 1/(.1*(ohm));
  delay(j);
 

}
 // noTone(6);
  analogWrite(6, 0);
  delay(10);
}

Please, let me know if you have any recommendations. I am not an expert in Arduino programming.

« Last Edit: February 09, 2021, 06:21:23 pm by zoltanh »
 
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Offline kripton2035

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Re: finding short on motherboards with a shorty (with display)
« Reply #10 on: February 09, 2021, 07:09:22 pm »
some work in progress ...
 

Offline zoltanh

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Re: finding short on motherboards with a shorty (with display)
« Reply #11 on: February 09, 2021, 07:33:55 pm »
Very nice. I like it.
 

Offline kripton2035

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Re: finding short on motherboards with a shorty (with display)
« Reply #12 on: February 09, 2021, 07:39:55 pm »
Quote
I have attached a picture of PCBA (THT) with LCD (I2C) not attached to it and SMD PCB
I don't see this picture ? can you post a picture with some measurment on the lcd please ?
 

Offline zoltanh

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Re: finding short on motherboards with a shorty (with display)
« Reply #13 on: February 09, 2021, 07:52:58 pm »
I did not upload the picture with LCD attached as I had not an available one and I borrowed one from other device and the setup was temporarily and I did not take the picture at the time. I ordered a LCD and in one or two days will arrive and then I will post the pictures with measurements.
 

Offline zoltanh

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Re: finding short on motherboards with a shorty (with display)
« Reply #14 on: February 10, 2021, 07:18:24 pm »
I remade the temporary LCD setup and made this short movie.
This is the link:

https://youtu.be/kG4-mmwKYAE

I uploaded herein a picture of 1 ohm resistor' s measurement.
 
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Offline kripton2035

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Re: finding short on motherboards with a shorty (with display)
« Reply #15 on: February 10, 2021, 07:27:44 pm »
this white lcd is really nice, very bright and readable.
 

Offline kripton2035

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Re: finding short on motherboards with a shorty (with display)
« Reply #16 on: February 10, 2021, 08:20:21 pm »
this is my work of the day.
 
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Offline natman69

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Re: finding short on motherboards with a shorty (with display)
« Reply #17 on: February 10, 2021, 09:16:52 pm »
I think the final design will be really really good  :-+
 

Offline zoltanh

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Re: finding short on motherboards with a shorty (with display)
« Reply #18 on: February 10, 2021, 09:18:52 pm »
Super!! Very nice! I hardly can wait to see your project.
 

Offline kripton2035

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Re: finding short on motherboards with a shorty (with display)
« Reply #19 on: February 11, 2021, 06:58:06 pm »
new work. implantation seems final. now the routing.
 
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Offline Fraser

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Re: finding short on motherboards with a shorty (with display)
« Reply #20 on: February 11, 2021, 09:05:35 pm »
Looking very nice  :-+

Fraser
 

Offline BrokenYugo

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Re: finding short on motherboards with a shorty (with display)
« Reply #21 on: February 12, 2021, 04:53:26 am »
I really needed one of these a few months ago, nifty idea. Might have to build one just to find the shorted part I gave up on finding.
« Last Edit: February 12, 2021, 04:57:52 am by BrokenYugo »
 

Offline delfinom

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Re: finding short on motherboards with a shorty (with display)
« Reply #22 on: February 12, 2021, 01:30:54 pm »
Neat. More elegant than just attaching a 15A supply to a rail and waiting for the glow.
 

Offline kripton2035

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Re: finding short on motherboards with a shorty (with display)
« Reply #23 on: February 12, 2021, 02:54:30 pm »
Neat. More elegant than just attaching a 15A supply to a rail and waiting for the glow.
absolutely, or buying a $1000 thermal camera.
this tool should not cost more than $20
 

Offline sam_sam_sam

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Re: finding short on motherboards with a shorty (with display)
« Reply #24 on: February 15, 2021, 10:07:15 pm »
some work in progress ...

I would be interested in a kit if you decided to make one available

Please let us know if you decided to do a kit for this project

Thanks
« Last Edit: February 19, 2021, 02:08:02 am by sam_sam_sam »
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