Asicminer BE Blade hw troubleshooting

[abec]

I was upgrading the clock and speed on the last of my blades, and I got in a hurry.  I think what may have happened is a resistor bridged due to negligence on my part, but I am not 100% sure. 

The symptoms are the device does not power on ( no LED light when it first plugs up to power ).  I tried replacing the fuse, but to no avail.  I am trying to figure out what I can try and do next.  The device was powering on but I had received XXXX for that bank, after I replaced the resistor and plugged it up to check results, it no longer would sync to the network and the green light stopped blinking, after that it never again would 'boot' up ( that initial green blink when you plug it up ).

I am plugging it into a blade backplane, tried a few different ports, I'll try plugging up to the 4 pin power, but I expect the same results.

Thanks for any help.

[sidehack]

Check your 3.3V either at the test header by the ethernet controller, or measure across C286 (which is an output cap for the 3.3V regulator, and should measure 3.3V at all times). Some folks that messed up resistors on the VRMs (usually missing or bad connection, haven't heard about a bridge yet) have reported that it fried that regulator.

[dentldir]

I ended up having two cold soldier joints on two feedback resistors that I swapped and got to this point on one blade.  Swapping out the regulator didn't get it back up and running. 

I believe something in the 3.3V section got shorted to ground leaving R120 and R121 in parallel instead of acting as a divider which would set the regulator at 3.3V.  Both of them are reading about 1.81k instead of one being 3 times the other.  Someone else said that swapping out IC70 didn't help either.

I suppose the right test is to lift everything that might be driven by 3.3V until R120 and R121 read correctly but I haven't had the time.  Any better ideas or information would be appreciated.

[abec]

Check your 3.3V either at the test header by the ethernet controller, or measure across C286 (which is an output cap for the 3.3V regulator, and should measure 3.3V at all times). Some folks that messed up resistors on the VRMs (usually missing or bad connection, haven't heard about a bridge yet) have reported that it fried that regulator.

I checked the power at the debug and C286, I am getting .8 volts at both locations, on my other devices they are all getting 3.3V at those locations.  I checked the power coming in, its 12.8v, C284 is 12.8v, C285 and C286 are both 0.8v.

R120 is doing .6v but on my other units its doing 2.5v

Where do you think I should try and go from here.  Sorry it took so long, I just got back from vacation.