Asus Rt-n66U short circuit & no boot.....

[Raga]

Hello guys am a newbie here, so pls bare with me, yesterday something went very wrong with my router which is Asus RTn-66u, it was the power button that stopped working and i had to put a rubber band around it to make it work, i decide to take it to service centre so they might be able to fix it, but those guys told me they dnt have a replacement button and router's warranty had finished, so i asked them how can i fix it, they told me to give it in local shop and solder the switch joints so that it can be in continuous "ON",they disagreed to solder it as they don't touch products out of warranty... then i gave it in a local shop and asked to find the switch and solder it so,he soldered it and was working perfectly at first then accidentally he short circuited the positive and negative terminal there was only a little spark and the power adapter seem to have cut the power after reconnecting the pin my router seem to have gone nuts, its blinking 3-4 led's constantly and on connecting lan cable router is not detected it shows "x" mark on network connection, no wifi signal either, there is one small micro controller on the back side which is super heating on connecting the power i was using merlin 378.55 firmware, i hope there must be a way to bringing the router back to life and only you guys know how and i dnt want to waste money in buying again the same model because this is one heck of a router i had, instead i will donate some money to this forum ....
uploaded a video at youtube of the router functioning after the short circuit, also attached images to this thread..

just guide me how to fix it guys.. ty

 

[geo44]

I would suggest checking the power supply adapter first to see that its outputting 19 volts.

 

[bbsc]

The problem is that the switch has three contacts.
Two of them are connected when "off" and two when "on".
If you're going to solder it "continuous on" then you must remove the switch first or you'll short circuit the power.

 

[mstombs]

The N66U has a number of FR9888 switching voltage step down chips, I am not sure if your problem is one, they are rated at 3A and will run hot if there's a problem downstream. They are supposed to have internal current limiting but I have seen a burnt out one (U32). Not easy to replace since the underside is a ground plane/heatsink, and definitelynot economic if you have to pay someone to do it!

 

[apvm]

+1 to geo44, check your power supply first.

 

[Raga]

I would suggest checking the power supply adapter first to see that its outputting 19 volts.

power output reads about 18.8-18.9V, so its normal i guess......

 

[Raga]

The N66U has a number of FR9888 switching voltage step down chips, I am not sure if your problem is one, they are rated at 3A and will run hot if there's a problem downstream. They are supposed to have internal current limiting but I have seen a burnt out one (U32). Not easy to replace since the underside is a ground plane/heatsink, and definitelynot economic if you have to pay someone to do it!

Hi, are you referring to one of these
http://www.aliexpress.com/item/SMD-FR9888-LCD-power-chip-SOP-8-original-authenc/32299203172.html
and are you sure its same chip coz its written fr9886 on the overheating chip though i cant read it properly its all erased due to overheating...and this time i let the router running for 10 min the cluster of those mini capacitors were very hot could that be a sign of routers processor is a toast?

 

[mstombs]

U1 i definitely seems to be a FR9886, a 2A version of the 3A FR9888, but this site labels it as 9888

http://wl500g.info/album.php?albumid=28&attachmentid=8999

Running hot probably normal - the component in the middle of that cluster is jut labelled 'A' but a processor is on other side of board

I concur with this

The problem is that the switch has three contacts.
Two of them are connected when "off" and two when "on".
If you're going to solder it "continuous on" then you must remove the switch first or you'll short circuit the power.

Has the switch been removed?

 

[Raga]

U1 i definitely a FR9886 seems to be a 2A version of the 3A FR98888. Running hot probably normal - the component in the middle of that cluster is jut labelled 'A' but a processor is on other side of board

I concur with this



Has the switch been removed?

"no" the switch is still there but it is soldered to be in continuous on...its running hot it could probably melt its own solder and could come off, i cant even touch it... is that normal to be that hot? i cant pin point its the component that is labelled "A" or the processor, i believe it might be the processor coz i never seen the heatsink that could go very hot on running for 10 min!

 

[apvm]

power output reads about 18.8-18.9V, so its normal i guess......

Did you try to ask your local shop to pay for the damages since it was them who ruined your router.

 

[Raga]

Did you try to ask your local shop to pay for the damages since it was them who ruined your router.

Dude, i cant and wont it was my responsibility to give it in a shop who repairs old radios and dvd's and basically these guys are having tiny shop but have good skill on electronics...

 

[TonyH]

+1 to geo44, check your power supply first.

If AC adapter is OK, there maybe a pico fuse on the board which is blown. Other than that if OP has some
test tools like good multi meter, and O'scope, Huntron, etc. Time to get a replacement router. Asus always
uses 19V DC power source which is unique already. One reason I never power off router.

 

[apvm]

Dude, i cant and wont it was my responsibility to give it in a shop who repairs old radios and dvd's and basically these guys are having tiny shop but have good skill on electronics...

You are a very good customer.

 

[Raga]

You are a very good customer.

 

[Raga]

If AC adapter is OK, there maybe a pico fuse on the board which is blown. Other than that if OP has some
test tools like good multi meter, and O'scope, Huntron, etc. Time to get a replacement router. Asus always
uses 19V DC power source which is unique already. One reason I never power off router.

So the router is a useless brick now, there no way of fixing it?