RT-AC68U hardware issue - no RF output

[methuselah]

Hi,
I've got an AC68U (Revision E1) and it's got no RF output.
The switcher IC U2 (FitiPower FR9618) is damaged and has no output. This is the supply that in some form goes to the 2.4GHz and 5GHz RF amps so that's not suprising. There may be other faults but I'll work through.

So, if there's anyone out there with an RT-AC68U with the case off, and handy with a multimeter could they measure the voltage on pin 3 of U2 please and let me know. I think it should be 2.85V but not entirely sure.

Many thanks in advance.

EDIT: Originally wrote 1.85V by mistake but meant 2.85V.

 

[TonyH]

Hi,
I've got an AC68U (Revision E1) and it's got no RF output.
The switcher IC U2 (FitiPower FR9618) is damaged and has no output. This is the supply that in some form goes to the 2.4GHz and 5GHz RF amps so that's not suprising. There may be other faults but I'll work through.

So, if there's anyone out there with an RT-AC68U with the case off, and handy with a multimeter could they measure the voltage on pin 3 of U2 please and let me know. I think it should be 1.85V but not entirely sure.

Many thanks in advance.

 

[TonyH]

Trying to repair it? Lots of time on hand? Even if you suspect that chip, finding replacemnt maybe difficult.
Also you'll need little more than multimeter to work on this type of problem. Ideally Huntron will make things easy or RF sniffing probe. Good luck.

 

[methuselah]

Trying to repair it? Lots of time on hand? Even if you suspect that chip, finding replacemnt maybe difficult.
Also you'll need little more than multimeter to work on this type of problem. Ideally Huntron will make things easy or RF sniffing probe. Good luck.

Yep! That device is definately shot, no doubt about it. Others may be down the line.
I can source the parts, but want to bench test it before I order anything. And based on that will depend on if I bother. But I like a challenge
RF is not an issue.

Thanks

 

[methuselah]

I've got the 5GHz network up on my bench setup by providing 2.85V - best guess without removing the screening can/heatsink is U2 provides the VREF for the 5GHz Skyworks devices.
2.4GHz network is still low signal but that can wait for another day.

Would still be very grateful if someone could confirm the supply generated by U2.
Thanks

 

[methuselah]

Well sadly didn't get any replies so worked through it back at the time, and just the regulator was gone.
After checking the regulator programming resistors confirmed it's actually 5V expected output on that regulator.
I ordered this and it's been running this for some time OK.

Might help someone in the future.