Badcaps.net Forum
Go Back   Badcaps Forums > Electronics Theory and Troubleshooting > General Electronics Technical Discussion
Register FAQ Members List Social Groups Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 02-25-2012, 06:33 AM   #1
Koda
Badcaps Veteran
 
Koda's Avatar
 
Join Date: Aug 2011
City & State: Prilep
My Country: Macedonia
Line Voltage: 220v AC
I'm a: Professional Tech
Posts: 281
Default How do I test integrated circuits with a multimeter?

I know how to check other components but IC's are always a pain in the a**. I don't have any expensive equipment to test it with, only a multimeter. Also I'd like to know how to test smd resistors and capacitors without desoldering them off the board. Any help is greatly appreciated.
__________________
Guns don't solve problems. I'll take 12
Koda is offline   Reply With Quote
Old 02-25-2012, 07:33 AM   #2
ratdude747
Rebooting...
 
ratdude747's Avatar
 
Join Date: Nov 2008
City & State: New Albany, IN
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Student Tech
Posts: 12,364
Send a message via Yahoo to ratdude747 Send a message via Skype™ to ratdude747
Default Re: How do I test integrated circuits with a multimeter?

you can't with the resistors and caps... they have to be out of circuit to be tested (otherwise you are testing the whole circuit, which often has other devices in parallel, messing up thee test)

as for ICs, depends on the IC. get a bench PSU, a solderless breadboard, and breadboard wires and build a sample circuit as per the device datasheet.
__________________


(Insert signature here)
ratdude747 is offline   Reply With Quote
Old 02-25-2012, 10:21 PM   #3
severach
Badcaps Veteran
 
Join Date: Aug 2007
City & State: Michigan
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist Tech
Posts: 983
Default Re: How do I test integrated circuits with a multimeter?

The best you can expect is to find shorts where they are not supposed to be. Get the datasheet and find out what the pins do. Some pins are supposed to be shorted. No shorts allowed between power and ground.
severach is offline   Reply With Quote
Old 02-26-2012, 06:07 AM   #4
Koda
Badcaps Veteran
 
Koda's Avatar
 
Join Date: Aug 2011
City & State: Prilep
My Country: Macedonia
Line Voltage: 220v AC
I'm a: Professional Tech
Posts: 281
Default Re: How do I test integrated circuits with a multimeter?

This is going to be a bit of an effort for me but will give both approaches a go and see which one works better. Thanks for the suggestion guys. If anyone else has any more ideas I would like to hear them.
Koda is offline   Reply With Quote
Old 02-26-2012, 06:24 AM   #5
Tube_Dude
Member
 
Tube_Dude's Avatar
 
Join Date: Feb 2011
City & State: Portugal
Posts: 49
Default Re: How do I test integrated circuits with a multimeter?

With a multimeter, you can't do a really serious test about the IC, but if you have a good new IC, the same type of the suspect one, you can compare readings and maybe you can spot any significant difference...
Tube_Dude is offline   Reply With Quote
Old 03-01-2012, 04:26 PM   #6
Agent24
Fuhjyyu Killer
 
Agent24's Avatar
 
Join Date: Oct 2007
City & State: Behind a soldering iron
My Country: New Zealand
Line Voltage: 230V AC 50Hz
Posts: 1,958
Default Re: How do I test integrated circuits with a multimeter?

There is no easy way to function test ICs except perhaps basic logic gates - of course you can check any IC for dead shorts, though.

Since they all have completely different designs and functions, the only real good test is in the circuit it was designed for, and verify by substitution.

Quote:
Originally Posted by Koda View Post
Also I'd like to know how to test smd resistors and capacitors without desoldering them off the board. Any help is greatly appreciated.
The same way to test a non-SMD part - you can measure it as long as it's not in parallel with anything else, or connected to any other circuitry that can throw off the measurements.

If in doubt, you still have to remove it and test out of circuit. There is no way around that.
Agent24 is offline   Reply With Quote
Old 03-02-2012, 05:15 AM   #7
Koda
Badcaps Veteran
 
Koda's Avatar
 
Join Date: Aug 2011
City & State: Prilep
My Country: Macedonia
Line Voltage: 220v AC
I'm a: Professional Tech
Posts: 281
Default Re: How do I test integrated circuits with a multimeter?

I hoped to avoid removing dozens of smd capacitors and resistors from boards to test them.
Koda is offline   Reply With Quote
Old 03-02-2012, 06:34 AM   #8
PlainBill
Badcaps Veteran
 
PlainBill's Avatar
 
Join Date: Feb 2009
City & State: Phoenix, AZ
My Country: USA
Line Voltage: 120VAC 60Hz
I'm a: Hobbyist
Posts: 7,013
Default Re: How do I test integrated circuits with a multimeter?

Quote:
Originally Posted by Koda View Post
I hoped to avoid removing dozens of smd capacitors and resistors from boards to test them.
It's possible to do this if you have a schematic. Even without a schematic it may be possible to spot a gross problem. Part of the challenge is knowing what the circuit does.

With a schematic you can check the value of the resistors and capacitors and use a 'not less / greater than' rule. A good resistor in circuit will never read greater than it's true value because parallel resistances will reduce the resistance. A good capacitor in circuit will never read less than it's rated capacitance because any parallel capacitances will increase the capacitance.

PlainBill
__________________
For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.
PlainBill is offline   Reply With Quote
Old 03-03-2012, 07:22 AM   #9
Koda
Badcaps Veteran
 
Koda's Avatar
 
Join Date: Aug 2011
City & State: Prilep
My Country: Macedonia
Line Voltage: 220v AC
I'm a: Professional Tech
Posts: 281
Default Re: How do I test integrated circuits with a multimeter?

I guess I'm gonna have to learn how to read schematics. BTW can ic's be checked the same way?
Koda 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


All times are GMT -6. The time now is 03:19 AM.


Badcaps.net Technical Forums 2003 - 2014
Powered by vBulletin ®
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.