Solving a shortcircuit on Analog Discovery 1

[Virus]

Hi everyone,

I was trying to solve a persistent problem on my Analog Discovery because at first it had a worn USB contact so I replaced it with a spare part, expecting it to work properly, but apparently now it has a short-circuit.

When I connect it to USB, it consumes about 640mA of current from my computer's USB. I tested it with a phone charger with higher current capacity as well and it also consumed 640mA.

When trying to pinpoint where is the problem, one of the components between the FTDI chip and the USB connector heats very much. I would like to know which are the values of those components so I can repair my Analog Discovery device.

Thanks.

[attila]

Hi @Virus

The excessive consumption/heating of the USB controller probably indicates that it is damaged.
Such could happen due to high USB voltage and in this case other ICs may be damaged as well.

[Virus]

8 minutes ago, attila said:

Hi @Virus

The excessive consumption/heating of the USB controller probably indicates that it is damaged.
Such could happen due to high USB voltage and in this case other ICs may be damaged as well.

Thanks for the info! I hope that's not the case and it's only a problem of those components, which I'll try to get somehow.

There is nothing that might make me suspect of an usual USB supply abnormal voltage besides, maybe, some static. I also never used the oscilloscope with too high voltages. The only problem I used to have is bad USB contacts, which was getting very annoying when the device last worked.

[attila]

Hi @Virus

Check for short at 1. The missing 1uF (2) should not affect since there is additional 0.1 and 10 on this rail.

[Virus]

Hi!

I realized this component was missing as well. Can you lead me to replace it please?

[attila]

Hi @Virus

That was a PRG18BB470MB1RB, similar to R145 but on AWG2 output:
https://digilent.com/reference/test-and-measurement/analog-discovery/reference-manual#awg_out

Is the digital part of the device working, USB controller... ?