How to test ceramic caps on cell phone boards

[Phonezone]

Hello everyone , its my first thread, and just want to say im happy to have found such great community on the web, where i can know more about board level repairs. thank you

my question is how to test caps and resistors on cell phone board , like the one in the picture around the cpu for iphone 5c that got water damage and A6 IC is getting really hot once connected to battery and i have found from other threads that some caps might got burned. i have a fluke digital Multimeter for equipment

thank you

[Jack Crow]

Re: How to test ceramic caps on cell phone boards

PZ
We are in similar fields.
Your into phones, I have been fixing hand held two way radios that use similar kinds of parts.

Water damage. Give up.
It can do some insidious things that are very hard to fix.

My advice is to borrow / buy a low power (about 30x) stereo microscope. Nothing fancy is required. When you look at these boards with the instrument you will get a whole new prespective on how smt electronics is assembled and serviced.

I refer to it as soldering sand.

Keep it safe
Jack Crow

[stj]

Re: How to test ceramic caps on cell phone boards

a friend of mine uses a cheap usb microscope mounted in a drill-press.

it works really well.

[Phonezone]

Re: How to test ceramic caps on cell phone boards

PZ
We are in similar fields.
Your into phones, I have been fixing hand held two way radios that use similar kinds of parts.

Water damage. Give up.
It can do some insidious things that are very hard to fix.

My advice is to borrow / buy a low power (about 30x) stereo microscope. Nothing fancy is required. When you look at these boards with the instrument you will get a whole new prespective on how smt electronics is assembled and serviced.

I refer to it as soldering sand.

Keep it safe
Jack Crow

Thank you Jack Crew for the replay
I have ameScope that get pretty good scope on cell phone boards, with water damage repair service i follow some steps
1- disassemble phone and take shields off.
2- clean with brush and isopropyl alcohol .
3- give the board a bath in ultrasonic machine with heat control for up to 30 minutes , i have from 60-70% success rate till this step
4- if board did not work or missing a function like LCD or back light not working then i put it under the microscope for visual inspection like corrodet connector or a filter , resistor that need a solder reflow, usually this bring me up to another 5-10% success rate.
After that i meet issues that i cant track visually which i think good testing skills is what im missing.
Like for this phones case i researched that mostly heating Chip is due to burned capacitor. And I see many people had success finding the faulty part , so it can be done just im still a newbie to SMT testing and schematics readings .
I found this article that talks about what i means
https://www.ifixit.com/Wiki/Troubles...ard_components
Regards

[Phonezone]

Re: How to test ceramic caps on cell phone boards

a friend of mine uses a cheap usb microscope mounted in a drill-press.

it works really well.

I have this one too , but im sure he just knows what he's doing , i have the equips but i don't have the skills yet

[Nerfinator]

Re: How to test ceramic caps on cell phone boards

What kind of "ultrasonic machine" are you using and what is it's purpose? What is the circuit board "bathing" in?

[budm]

Re: How to test ceramic caps on cell phone boards

http://bluewaveinc.com/ultrasonic-cleaning-101/

http://www.bransonic.com/
or cheap stuff from HF
http://www.harborfreight.com/25-lite...ner-95563.html

[Nerfinator]

Re: How to test ceramic caps on cell phone boards

That's really interesting. Is it worth the investment though? I mean, I know that it depends on how many water damaged devices you get in, but I mean from a "does it really work" point of view.

[Phonezone]

Re: How to test ceramic caps on cell phone boards

That's really interesting. Is it worth the investment though? I mean, I know that it depends on how many water damaged devices you get in, but I mean from a "does it really work" point of view.

If you are in cell phone repair business then that a must have . Some people just use brush and alcohol to clean corrosion , but the ultrasonic waves gets what you can't see. Get one with heat control.
Here's affordable one http://www.ebay.com/itm/Solid-Tech-1...item2ed2701aff

[Nerfinator]

Re: How to test ceramic caps on cell phone boards

If you are in cell phone repair business then that a must have . Some people just use brush and alcohol to clean corrosion , but the ultrasonic waves gets what you can't see. Get one with heat control.
Here's affordable one http://www.ebay.com/itm/Solid-Tech-1...item2ed2701aff

Thank you Phonezone. I do a lot of cell phone repair and yeah, when it comes to water damage I just use a soft bristle toothbrush and 95% iso alcohol to clean corrosion.

What do you use as a solvent in the bath? My online research says to use Ammonia Hydroxide but I'd rather find out what is used in practice rather than make a mistake on someone's $$$$ cell phone or tablet.

[stj]

Re: How to test ceramic caps on cell phone boards

Freon was best before they banned it.

[dlaroche]

Re: How to test ceramic caps on cell phone boards

What do you use as a solvent in the bath? My online research says to use Ammonia Hydroxide but I'd rather find out what is used in practice rather than make a mistake on someone's $$$$ cell phone or tablet.

I too am curious as to what liquid is used.

[Nerfinator]

Re: How to test ceramic caps on cell phone boards

Yeah, that's what I read too. Freon, but that isn't an option these days. Still curious as to what liquid should be used.

[stj]

Re: How to test ceramic caps on cell phone boards

IPA if you can do it outdoors or stop it evaporating.

[techfixit]

Re: How to test ceramic caps on cell phone boards

I use a detergent made specifically for use in ultrasonic cleaners, it's manufactured by Allendale (Ultra+). I use 5-10% concentrated solution mixed with deionised water. I heat my solution to 60-70 degrees and generally leave the part/s in for a minimum of 30 minutes (15 minutes each side of the board). Once the cleaning process is finished i thoroughly rinse the part/s in 99% isopropanol and dry with compressed air.

I've successfully restored many dead iphone and ipad water damaged logic boards back to working condition with this process alone.

[stj]

Re: How to test ceramic caps on cell phone boards

"each side"??
you should put boards into the tank vertical so any crap falls away.

[techfixit]

Re: How to test ceramic caps on cell phone boards

"each side"??
you should put boards into the tank vertical so any crap falls away.

I don't lay the parts flat, I put them in vertically at a 45 degree angle. The cavitation process will generally clean the entire board at any angle but i like to do both sides anyway for peace of mind

[Longbow]

Re: How to test ceramic caps on cell phone boards

I'll throw in my 2 shillings worth on this subject. I agree that a microscope is a great tool for a variety of work. While wet or contaminated boards can often be salvaged in the short run, the time and expense is most often too great. And in many cases a reclaimed water damaged board will come back again as unseen corrosion continues to damage the parts and traces on the board. But sometimes you get lucky.

Water damage - it is rare that a board is damaged by pure distilled water. Typical types of water will be mud, cat "water", water from overturned house plants, detergent or cleaning sprays, and soft drinks and coffee. And don't leave out the most popular cell phone accident - toilet water.

But even then it matters how much time has elapsed since the damage. The "water" can creep slowly from the traces into the parts via corrosion that cannot be fixed or washed away. It is one thing to reclaim a well made glass board with through-hole components and another to ultrasound a cell phone. Just my opinion.

[fendy.efpe]

Re: How to test ceramic caps on cell phone boards

Thanks full

[DJ_MIX]

Re: How to test ceramic caps on cell phone boards

I enjoy the talk about ultrasonic, but how do we test cermanic caps?