No power at all, dead board, like to repair it

Thread Starter

tester2

Joined Mar 11, 2010
56
hi guys i need your help my linksys wrt54gs v4 router board look like this and this is dead no power at all, so i am trying to repaire to get power on it. please help me out how to find out burn out components on this board.

And i am new to this board testing i don't know how to check and what spot i have to adjust the switch to test components.


I am attaching a picture, i have to measured the voltage in the input jack and also the 3.3V after the power regulator? so where is the input jack & 3.3v after power regulator look like in the picture below.
so how to measure this and where i have to adjust switch on meter.

thanks

 

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R!f@@

Joined Apr 2, 2009
9,918
See the attachment.
1 .get a high resolution close ups of that area, I need to take closer looks. it's a must
2 .I need two pictures of the area in the square, from both the sides of the board.
3 .what type of DMM do you have and tell me ur electronics skill you posses
 

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Thread Starter

tester2

Joined Mar 11, 2010
56
this all are my board real pictures.
i am able to do soldering on the board, but i don't know how to check burn out components on board, so i like to know how to check components on board.
if i track/trace a component which is burn out then i can do very well replace it, i mean i can do soldering.

thanks.
 

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Last edited:

hwy101

Joined May 23, 2009
91
Do you have the original power supply that came with that router?
It should be rated at 7.5 volts DC it's actually higher than that with no load, then it's regulated inside the unit.
 

R!f@@

Joined Apr 2, 2009
9,918
See the attachment.
One problem that you did not do what I said.
when I zoom in I cannot get a clear view of the area I want to check, this makes things difficult.
Now the below things are assumptions made by the low res of the pick as I cannot be sure of what I am seeing.

But this might help.
see the area in the red lines, this the area I need to concentrate on for now.
see the label fuse. I want you to check for zero resistance of that component for now and post back. don't try to take it out yet, in fact don't do any think except measure the resistance.
If possible try to get closeup pictures with better lighting.
 

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Thread Starter

tester2

Joined Mar 11, 2010
56
Am I going blind or does the 2nd set of picture show a different board than the picture in the OP.
in post #1 is not my board picture.

but in post #3 is my real wrt54gs v4 Linksys Router board pictures.

i tried many diffrent power suplies from 7v to 12v none work at all.
 

retched

Joined Dec 5, 2009
5,207
i tried many diffrent power suplies from 7v to 12v none work at all.
Uh oh. Which one did you start with? The 12v may have applied upwards of 15v hopefully not frying anything else.. I believe you should be using a 5.

By the way, did you check the wall outlet to see if there is power there?

I had a friend who swore up and down his TV was broke.. Had it in pieces when I got there. It was starting to get dark so I grabbed a lamp to bring over, plugged it in and guess what? The TV was fine. The GFCI tripped.
 

Thread Starter

tester2

Joined Mar 11, 2010
56
on the yellow 2 legs component written this [P 30V, NR 3H] just now i take few clear pictures of this spot.

and i put switch on meter at 20k then i touch black & red wires to yellow component either way exchange wires shows 0.00 only on yellow component.
 

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R!f@@

Joined Apr 2, 2009
9,918
Next step it to check power.
Plug in the original adapter, power it up.
Put the DMM in DC Voltage mode.
In the picture, I have labeled ground, this is you negative point, connect the black meter probe and keep it connected throughout the measurement
Next use the red probe to measure the voltage at the points I have labeled 1 via 8.
Note them and post back.
Be sure that power is available at the adapter output
 

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Thread Starter

tester2

Joined Mar 11, 2010
56
Next step it to check power.
Plug in the original adapter, power it up.
Put the DMM in DC Voltage mode.
In the picture, I have labeled ground, this is you negative point, connect the black meter probe and keep it connected throughout the measurement
Next use the red probe to measure the voltage at the points I have labeled 1 via 8.
Note them and post back.
Be sure that power is available at the adapter output
what is DMM & how to put in DC mode. And i like to know if i connect adapter & power ON in this situation can i check the spotes with meter when power is ON.
 

R!f@@

Joined Apr 2, 2009
9,918
We need to check voltage..put the meter in the range to which you measure dc voltage.
You have to power the board using the adapter. then only you can get the voltage

DMM.. digital multi meter.
Put it in DCV 20 and do the testing
 

Thread Starter

tester2

Joined Mar 11, 2010
56
We need to check voltage..put the meter in the range to which you measure dc voltage.
You have to power the board using the adapter. then only you can get the voltage

DMM.. digital multi meter.
Put it in DCV 20 and do the testing
meter put on 20 DCV & Black wire connect to Ground with out moving then Red wire moving fron spot 1 to 8 the below are the readings here

Spot 1- 0.00 , 2-0.00 , 3-0.00 4-15.50 , 5-15.45 , 6-15.50 , 7-15.48 , 8-15.46
 
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