using 12V power adapter on a 9V wifi modem?!

Thread Starter

rezamoezzi

Joined Dec 28, 2015
1
I used an 12V adapter for my modem(philips SNB5600) instead of 9 volt.
It was working but just after 10 seconds it made a noise and It didn't work anymore.
So I want to ask,what exactly happened and is there any hope to fix it and how can I repair it?
Thanks
 

bertus

Joined Apr 5, 2008
20,564
Hello,

You will have burnt someting inside the modem.
It was rated for 9 Volts and you applied 12 Volts, so over voltage might lead to over current and burning stuff.

Bertus
 

Roderick Young

Joined Feb 22, 2015
408
If you have a multimeter, check the voltage on the 12V adapter. Is it really 12 volts? Maybe it was an old unregulated type, and due to the light load, had a much higher voltage.

As to what happened, was the sound like something popping? What did it sound like? Was there a smell, especially a burning smell? Open the modem, looking especially for burned components or bulging / leaking capacitors. Post a picture here, if you can. The most reliable thing to do would be to simply get a new modem rather than trust one that has been exposed to overvoltage, but I'm assuming you're interested in what happened.
 

Alec_t

Joined Sep 17, 2013
11,388
Any resistive component receiving 12V instead of 9V would generate 78% more heat than it was designed to! Not surprising if something fried :(.
 

dl324

Joined Mar 30, 2015
10,921
So I want to ask,what exactly happened and is there any hope to fix it and how can I repair it?
No one can tell you exactly what happened or how to repair it.

Chalk it up to experience. Buy a new one and pay more attention to details in the future.
 

ian field

Joined Oct 27, 2012
6,539
The adapters may also have had different polarities - zap!
Wouldn't have worked for a while if that happened.

Most modems I've ripped for parts, had at least 3 SMPS regulators for on board rails - some are buck with series control transistor/MOSFET, if they fail short circuit; the unregulated juice hits the logic supply rails and its game over.
 
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