[Hackrf-dev] More troubleshooting of the dead HackRF One

[C Crane]

Probing for voltages I get 5v out of the USB through the associated filter
components and the mosfet as normal. 5v However when I go to the U21
voltage converter section things fall apart. There are the two pairs of two
10 uF capacitors there. One pair is on the the 1.8v side and one pair is on
the VCC side. The pair on the VCC are both indicating continuity to ground.
The 1.8v pair do not. I probed further and discovered the entire VCC BUS is
indicating continuity to the ground which of course makes sense being it's
a BUS.

I guess I will pull the two VCC u21 caps and see if the BUS is still
clamped. I'm just at a loss right now as to what could be causing a dead
short to ground and where in the entire BUS it exists.

Also, prior to realizing this condition I noticed the U21 converter emitted
a very slight high frequency whine when I probed the two aforementioned VCC
BUS caps near it while the unit was plugged into the USB port. I assume
this means the converter is at least alive and trying to produce the proper
voltages?

I'm kind of surprised the computer doesn't bonk and complain about
excessive USB current draw when the device is plugged in since the VCC is
indicating ground. I have one of the little usb voltage current pass
through OLED meters. I will plug it into that and see what is indicated
when I am home from work. (I'm hiding from work in my office trying to
troubleshoot this)

I hope I'm not being annoying with my messages here but I'm just looking
for some advice or ideas as to what might be wrong.

Thanks,

Casey
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