Looking at it with the naked eye and magnifiers it looks normal (admittedly difficult to see as its so small!)

Is the only way to check to desolder it?

Yes remove it and check it for shorts.

 

Does it not have the option to use a 10A scale? I'm not surprised that the router draws more than 200mA.
Another approach is to measure the voltage across a low ohms resistor while under load. For instance, finding 0.9V across a 1Ω resistor (in series with the power to the router) would tell you it's drawing 900mA.

I bought a new multimeter that has 10A option. Testing the router shows it flashing periodically 0 to -0.654 and other random negative numbers.

 

That sounds like it's taking too much current from the psu, probably because its got a short on the supply line, or the psu isn't upto scratch, did you remove the diode in post#15??

 

I'd also continue testing the power supply. Got any 12V lightbulbs? Ideally you'd have one that draws at least half the rated current of the PSU. For instance 1A at 12V is 12W, and so a 10W bulb would show directly whether the PSU is up to the job. If the bulb lights, you've eliminated the PSU as the culprit.

 

That sounds like it's taking too much current from the psu, probably because its got a short on the supply line, or the psu isn't upto scratch, did you remove the diode in post#15??

I haven't yet. Id need to remove the switch to be able to get to it. I will get around to it at some point.

 

I'd also continue testing the power supply. Got any 12V lightbulbs? Ideally you'd have one that draws at least half the rated current of the PSU. For instance 1A at 12V is 12W, and so a 10W bulb would show directly whether the PSU is up to the job. If the bulb lights, you've eliminated the PSU as the culprit.

I've tried about three different 12v 1A PSUs and they all work fine in other devices.

 

I've tried about three different 12v 1A PSUs and they all work fine in other devices.

A 12V 1A supply should always work if it’s laid needs 1A or less (usually less!). But connect sometime that needs 2A, 3A and it won’t work. Anything more than the 1A it is rated for.
The other devices in which the PS worked required less than 1A. That’s why we need to locate he short or measure the current o

 

I'd also continue testing the power supply. Got any 12V lightbulbs? Ideally you'd have one that draws at least half the rated current of the PSU. For instance 1A at 12V is 12W, and so a 10W bulb would show directly whether the PSU is up to the job. If the bulb lights, you've eliminated the PSU as the culprit.

Iv'e tested the psu's with a 12v fan controller and a cob led. Lights up fine. Using multimeter to test current, it reaches the 0.6A the led requires.

 

Iv'e tested the psu's with a 12v fan controller and a cob led. Lights up fine. Using multimeter to test current, it reaches the 0.6A the led requires.

Okay, that considerably reduces the odds of the PSU being the problem. It should be able to produce the rated current at the rated voltage, though, and until I've seen that proof, there is still a chance the PSU is a problem. Like I said, the odds have now come WAY down, but they aren't yet zero.

I'm being a stickler on this issue because in my experience, most devices fail because of a failed PSU. I never even begin to look elsewhere until I rule that out completely.

 

@Bassquake Did you manage to identify the culprit? I have the exact same problem.

 

@Bassquake Did you manage to identify the culprit? I have the exact same problem.

Sorry no. I havent had time to have a good go with it. Will do eventually!