Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Power Supplies and Power Supply Design
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 01-02-2015, 06:08 PM   #1
CDGraves
New Member
 
Join Date: Apr 2013
City & State: Latrobe, PA
My Country: USA
I'm a: Knowledge Seeker
Posts: 15
Default Magicjack power adapter failure

I use magicjack plus. It gives me land line phone service for a small fraction of what Comcast charges. It has been a good service so far.
For those not familiar. The magicjack plus is powered thru a USB port (5 volts). Magicjack can be powered directly from your computer, but that means magicjack will not work when the computer is not on. It also comes with a power adapter module that converts AC to a USB 5 volts. With this adapter, the magicjack can be powered from the wall AC and can run independent of your computer. If you power it with the AC adapter, you will need to connect the magicjack to your router with a Ethernet cable.
I normally have it powered from AC with the adapter, but the adapter recently failed, so I had to power it with my computer USB. The same thing happened to my sister. Searching the net, I discovered that magicjack power adapter fail a lot.

I decided to trouble shoot the problem. I measured the 5V output of the power module to be only 3.5V. I took the power module apart to figure out why it failed. I found two 220uF 10V capacitors that were labelled "Low ESR" (C8 and C9). I measured the ESR of these caps and C8 measured 1.5 Ohms. I replaced that cap and it fixed the problem. Output voltage restored to 5V. These electrolytic capacitors do not fail suddenly, they gradually deteriorate. The output voltage of the Magicjack power module will drop gradually until it hits a critical level. The MJ will start to behave sporadically, then it will die completely.
If the cap fails with an ESR of only 1.5 ohms, then it must really need a super low ESR.

I do not recommend repairing these power modules. I did it out of curiosity. These modules are very cheap.
Magicjack is aware of the problem and offers a replacement. To contact them, go to www.magicjack.com and go to "support". They will ship you a new power module for about $5.35. Some people have reported that the replacement modules from Magicjack are no better than the originals and have had repeat failures.
Consider getting a power module from another source. There are lots of AC to USB power converter modules available on Ebay for only a few dollars. Search Ebay for "magicjack power adapter".
Attached Images
File Type: jpg 100_3579a.jpg (293.0 KB, 72 views)
File Type: jpg 100_3582a.jpg (422.0 KB, 99 views)
File Type: jpg 100_3584a.jpg (285.6 KB, 106 views)
CDGraves is offline   Reply With Quote
Old 01-02-2015, 07:05 PM   #2
goontron
5000!
 
goontron's Avatar
 
Join Date: Dec 2011
City & State: South Greeley, Wyoming
My Country: US
Line Voltage: 13.9kv HT service and some 240v center tap oddity.
I'm a: Professional Tech
Posts: 4,029
Default Re: Magicjack power adapter failure

That is a nasty little brick. Toss it and use a USB phone charger.
__________________
Things I've fixed: anything from semis to crappy Chinese $2 radios, and now an IoT Dildo....

"Dude, this is Wyoming, i hopped on and sent 'er. No fucking around." -- Me

Excuse me while i do something dangerous


You must have a sad, sad boring life if you hate on people harmlessly enjoying life with an animal costume.

Sometimes you need to break shit to fix it.... Thats why my lawnmower doesn't have a deadman switch or engine brake anymore

Tomorrow Is Nearly Yesterday And Everyday Is Stupid!
goontron is offline   Reply With Quote
Old 01-13-2015, 08:39 AM   #3
pc7fan
Badcaps Veteran
 
Join Date: Aug 2013
City & State: Maritimes
My Country: Canada
Line Voltage: 250V Split-phased, 60 Hz
I'm a: Hobbyist Tech
Posts: 49
Default Re: Magicjack power adapter failure

Very naaty indeed, you may use a genuine phone charger (Samsung, LG, etc), this MJ charger by the looks of it are low quality crap.

Last edited by pc7fan; 01-13-2015 at 08:40 AM.. Reason: just because
pc7fan is offline   Reply With Quote
Old 04-17-2015, 07:35 AM   #4
ben7
Capaholic
 
ben7's Avatar
 
Join Date: Jan 2011
City & State: Trenton, NJ
My Country: USA
Line Voltage: 240/120V 60Hz
I'm a: Hardcore Geek
Posts: 3,989
Default Re: Magicjack power adapter failure

Just saw this thread.

I didn't realize it at first but a power adapter someone gave me recently is the same as this one! It didn't output more than 100mV or so (it was pulsing). One of the 220uF 10V "low-esr" caps had BULGED. That thing was ready to launch like a rocket!! Replacing it with a crappy capacitor, 10V 220uF, 5mm diameter, fixed it. Wonder how long it will last though xD
I did notice, that it's output when loaded with a 5 ohm resistor, is about 4.6V. Tried putting a (larger case size ) low esr cap on there and it went up to 4.99V :P

I have to say, it isn't that bad of a power supply. It's got good isolation, and a Y type cap. Also the output is filtered with a CLC filter. The control is done by some 6 pin smd chip. Not a silly self-oscillating design!

I would take a pic of the cap but I'll have to use a magnifying lens, my camera can't zoom in close enough (well, it can't focus).

-Ben
__________________
Muh-soggy-knee
ben7 is offline   Reply With Quote
Old 09-02-2015, 03:03 AM   #5
mmartell
Badcaps Veteran
 
Join Date: Oct 2013
City & State: Windsor ON
My Country: Canada
I'm a: Knowledge Seeker
Posts: 2,927
Default Re: Magicjack power adapter failure

Interesting find. My neighbour had been complaining about his magic jack and eventually stopped using it. He had blamed it on his internet/router which was probably a red herring. Will have to look into it for him.
mmartell 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 - 2021
Powered by vBulletin ®
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 11:15 PM.
Did you find this forum helpful?