Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Equipment Usage, Soldering, Techniques, and Reviews
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 03-14-2022, 08:30 AM   #121
badboydas
Noob
 
Join Date: Jun 2010
City & State: Wimborne
My Country: UK
Line Voltage: 240VAC 50Hz
I'm a: Knowledge Seeker
Posts: 20
Default Re: New tool to find short capacitors on motherboards : shorty with display

Anyone building Shorty should note that all MCP3421's are not equal, the SMD code dictates the address (which you would change in the code line 45)
If SMD code is
CAxx = 0x68
CBxx = 0x69
CCxx = 0x6A
CDxx = 0x6B
CExx = 0x6C
CFxx = 0x6D
CGxx = 0x6E
CHxx = 0x6F
some of you will have known this,some may not have

I have still have not got it fully working but it is now talking to the MCP3421 @ address 0x69
__________________
If it ain't broke I don't want it.
badboydas is offline   Reply With Quote
Old 03-24-2022, 09:07 AM   #122
clearchris
Badcaps Veteran
 
clearchris's Avatar
 
Join Date: Dec 2013
City & State: San Antonio
My Country: United States
Line Voltage: 120v 60hz / 240v 60hz
I'm a: Hardcore Geek
Posts: 606
Default Re: New tool to find short capacitors on motherboards : shorty with display

If there's a question of addresses, there are sketches included in the arduino gui where you can flash a program to the arduino and scan the i2c or spi bus for addresses.
clearchris is offline   Reply With Quote
Old 03-25-2022, 10:54 AM   #123
badboydas
Noob
 
Join Date: Jun 2010
City & State: Wimborne
My Country: UK
Line Voltage: 240VAC 50Hz
I'm a: Knowledge Seeker
Posts: 20
Default Re: New tool to find short capacitors on motherboards : shorty with display

Quote:
Originally Posted by clearchris View Post
If there's a question of addresses, there are sketches included in the arduino gui where you can flash a program to the arduino and scan the i2c or spi bus for addresses.
Yes you are right, but the code states
"0x68 is the default address for all MCP342x devices"
Not every one here would be a keen programmer.
badboydas is offline   Reply With Quote
Old 03-25-2022, 02:42 PM   #124
badboydas
Noob
 
Join Date: Jun 2010
City & State: Wimborne
My Country: UK
Line Voltage: 240VAC 50Hz
I'm a: Knowledge Seeker
Posts: 20
Default Re: New tool to find short capacitors on motherboards : shorty with display

And the line underneath,yeah come on this is hard work
uint8_t address = 0x69; // addresses do vary depending on smd code
badboydas is offline   Reply With Quote
Old 03-26-2022, 11:50 AM   #125
clearchris
Badcaps Veteran
 
clearchris's Avatar
 
Join Date: Dec 2013
City & State: San Antonio
My Country: United States
Line Voltage: 120v 60hz / 240v 60hz
I'm a: Hardcore Geek
Posts: 606
Default Re: New tool to find short capacitors on motherboards : shorty with display

Quote:
Originally Posted by badboydas View Post
Yes you are right, but the code states
"0x68 is the default address for all MCP342x devices"
Not every one here would be a keen programmer.
I have done some i2c work lately, and if I can't communicate with the chip, the first thing I do is scan for addresses, not to really check for the address, but to verify communication and wiring.

Hopefully I'd have noticed the different address, but I can't say for certain I would have.
clearchris is offline   Reply With Quote
Old 06-26-2022, 10:15 AM   #126
Erico1
New Member
 
Join Date: May 2022
City & State: Hollywood, Florida
My Country: USA
Line Voltage: 120VAC 60 Hz
I'm a: Knowledge Seeker
Posts: 6
Default Re: New tool to find short capacitors on motherboards : shorty with display

I am a member of the forum where the design work is being discussed for the shorty with display.

There is some recent activity on this project ( as of June 2022) in the thread.

The OP in the EEVlog forum mentioned possible selling the Gerber file for the PCB and I am definitely on board with that.
Erico1 is offline   Reply With Quote
Old 06-26-2022, 10:39 AM   #127
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 26,831
Default Re: New tool to find short capacitors on motherboards : shorty with display

gerbers arent the issue,
i could cad that up in an hour or so.

the issue is Kripton changed the circuit because it couldnt provide enough stable current.
and a full circuit with changes wasnt released.
stj is offline   Reply With Quote
Old 06-27-2022, 10:27 PM   #128
clearchris
Badcaps Veteran
 
clearchris's Avatar
 
Join Date: Dec 2013
City & State: San Antonio
My Country: United States
Line Voltage: 120v 60hz / 240v 60hz
I'm a: Hardcore Geek
Posts: 606
Default Re: New tool to find short capacitors on motherboards : shorty with display

That doesn't sound insurmountable. Couldn't we slap a linear regulator on there and get the current required?
clearchris is offline   Reply With Quote
Old 06-28-2022, 02:15 AM   #129
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 26,831
Default Re: New tool to find short capacitors on motherboards : shorty with display

can you get linear regulaters operating at sub-volt range?
these testers use very low voltage to avoid turning semiconductors on.
stj is offline   Reply With Quote
Old 06-30-2022, 10:30 AM   #130
clearchris
Badcaps Veteran
 
clearchris's Avatar
 
Join Date: Dec 2013
City & State: San Antonio
My Country: United States
Line Voltage: 120v 60hz / 240v 60hz
I'm a: Hardcore Geek
Posts: 606
Default Re: New tool to find short capacitors on motherboards : shorty with display

From the other thread, here's megaraider's 2c.

"The current source problem arises from using the 5V output line from the Arduino Nano.
As he wrote somewhere he couldn't figure out why the voltage (5V) dropped when the tips were connected. The LM1117IMPX-5.0 max. load current is 800mA.
While that might seem to be enough it's not: one must take in account the Arduino ICs, display, DAC, Op Amp and tips current source overall power consumption!
Therefore, replace that 5V line with a reliable 5V power supply."

5v regulators are very common, I'm pretty sure I have multiple types on hand even.

If that doesn't work, there is a schematic here for a series regulator, doesn't look that terrible. https://en.wikipedia.org/wiki/Linear_regulator

It's entirely believable that these nano clones use underpowered regulators. I would really be surprised if you were able to run them at 100% of spec.
clearchris is offline   Reply With Quote
Old 06-30-2022, 11:28 AM   #131
Per Hansson
Super Moderator
 
Per Hansson's Avatar
 
Join Date: Jul 2005
City & State: ----
My Country: Sweden
Line Voltage: 230v 50Hz
I'm a: Knowledge Seeker
Posts: 5,216
Default Re: New tool to find short capacitors on motherboards : shorty with display

It can apparently also have a uA78M05 regulator and that is only good for 500mA:
https://www.arduino.cc/en/uploads/Ma...0Schematic.pdf
__________________
"The one who says it cannot be done should never interrupt the one who is doing it."
Per Hansson is offline   Reply With Quote
Old 06-30-2022, 11:44 AM   #132
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 26,831
Default Re: New tool to find short capacitors on motherboards : shorty with display

so we need a 78s05?
stj is offline   Reply With Quote
Old 06-30-2022, 12:37 PM   #133
clearchris
Badcaps Veteran
 
clearchris's Avatar
 
Join Date: Dec 2013
City & State: San Antonio
My Country: United States
Line Voltage: 120v 60hz / 240v 60hz
I'm a: Hardcore Geek
Posts: 606
Default Re: New tool to find short capacitors on motherboards : shorty with display

Quote:
Originally Posted by Per Hansson View Post
It can apparently also have a uA78M05 regulator and that is only good for 500mA:
https://www.arduino.cc/en/uploads/Ma...0Schematic.pdf
And sub in some chinese regulator to make BOM for a 3 usd board, there's your voltage sag. Can't say I'm surprised. I almost never use the on board power to run peripherals.

We could easily use a 78s05 as stj suggested (in jest?). We probably need to change the nano power to use the 5v pin instead of the vin pin. It would probably be better to have everything use the same power source.
clearchris is offline   Reply With Quote
Old 06-30-2022, 01:02 PM   #134
Per Hansson
Super Moderator
 
Per Hansson's Avatar
 
Join Date: Jul 2005
City & State: ----
My Country: Sweden
Line Voltage: 230v 50Hz
I'm a: Knowledge Seeker
Posts: 5,216
Default Re: New tool to find short capacitors on motherboards : shorty with display

Well, you could use a regulator with a little bit better dropout voltage than 3000mV if you're going to power it from a battery I say!
I was looking for a replacement to my ESR tester and came across this 1117 with 350mV dropout and rated 1.2A it is a pretty nice upgrade over a standard 1117 at least:
ST LDL1117S50R: https://www.mouser.se/ProductDetail/...FiVf%2Fg%3D%3D
Per Hansson is offline   Reply With Quote
Old 06-30-2022, 01:07 PM   #135
clearchris
Badcaps Veteran
 
clearchris's Avatar
 
Join Date: Dec 2013
City & State: San Antonio
My Country: United States
Line Voltage: 120v 60hz / 240v 60hz
I'm a: Hardcore Geek
Posts: 606
Default Re: New tool to find short capacitors on motherboards : shorty with display

Sounds good to me, what do you think stj?
clearchris is offline   Reply With Quote
Old 06-30-2022, 02:36 PM   #136
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 26,831
Default Re: New tool to find short capacitors on motherboards : shorty with display

hard to believe that package can give 1.2A
i wonder how much copper groundplane it wants.
stj is offline   Reply With Quote
Old 06-30-2022, 02:54 PM   #137
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 26,831
Default Re: New tool to find short capacitors on motherboards : shorty with display

looking closer,
maybe we should run it at 3.3v
then we can use a lithium cell instead of a 9v battery that may only be good for a few hundred mA
maybe a 500mA cell from a disposable vape together with a usb charger/protection pcb

either way, the BC557 has to go.
a P-type mosfet would be better
stj is offline   Reply With Quote
Old 06-30-2022, 03:37 PM   #138
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 2,626
Default Re: New tool to find short capacitors on motherboards : shorty with display

A one or two transistor constant-current source is not difficult, and possible to voltage-limit it. On laptops, GPU etc. I could see a need to keep it under 2V max.
redwire is offline   Reply With Quote
Old 06-30-2022, 07:20 PM   #139
megaraider
Badcaps Veteran
 
Join Date: Jul 2015
City & State: Porto
My Country: Portugal
I'm a: Hobbyist Tech
Posts: 277
Default Re: New tool to find short capacitors on motherboards : shorty with display

Quote:
Originally Posted by clearchris View Post
From the other thread, here's megaraider's 2c.
"The current source problem arises from using the 5V output line from the Arduino Nano. (...)
Therefore, replace that 5V line with a reliable 5V power supply."
Quote:
Originally Posted by clearchris View Post
5v regulators are very common, I'm pretty sure I have multiple types on hand even. (...)
It's entirely believable that these nano clones use underpowered regulators. I would really be surprised if you were able to run them at 100% of spec.
[And above posts...]

My thoughts FWIW:
a)
Is portability so important (at least at this stage)?
We all know it will be sitting on our workbench... will it not!
For what's worth we can even power it from an rescued ATX power supply.

b)
It's much better to have everything connected to the same power source.
Bypass / tweak Arduino board to use it instead (that shitty regulator is for costs saving only).

c)
YES, the LDL1117 will be able to deliver over 1A output current just like an 'old' LM7805 is.
As always it comes down to the heat sink: it's never to small!
Moreover, want to boost output current to several amps? The 'old' 2N3055 will boost it... Again the heat sink comes into play!

d)
Yes that BC557 has to be replaced! It's farmost and basic for current source.
megaraider is offline   Reply With Quote
Old 07-01-2022, 01:46 AM   #140
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 26,831
Default Re: New tool to find short capacitors on motherboards : shorty with display

so lets use a chinese buck convertor
i think they can go down to 1.8v at 3A
stj is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2022
Powered by vBulletin ®
Copyright ©2000 - 2022, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 11:52 PM.
Did you find this forum helpful?