The TAU does use high density pcb’s And very small components. It is challenging to remove and replace components unless you are used to working on such densely packed pcb’s And have the appropriate equipment. A steady hand and very fine tip in the soldering iron are essential.
It is possible to substitute PCB’s but always consider the risk of doing so as boards with shorts can damage a good board that is providing the power.
If you have another thermal camera then I have a possible helpful idea. You need an adjustable constant current power supply. If you do not have one, it might even be worth investing in one as they are very useful and some Chinese models are quite affordable. If not, try to borrow one.
Set up the working VUE camera with a monitor and correct power supply. Position it so that it can view the TAU PCB with the DC-DC converters on it. Power the damaged PCB from a 5V power supply with its constant current set to 200mA. Watch the working VUE camera display and look for a hot spot forming on the damaged PCB where the short exists. You may see PCB tracks warming up, discrete components or one of the chips. You are trying to generated some visible heat energy in the short circuit loop. The ground plane is large so it is likely that you will see the positive feed path into the PCB and can see at what point it stops, that being the location of the short circuit. A short in a chip can cause increased heat at that relatively poor conduction point. Resistance = heat
If you cannot see anything with 200mA flowing in the short circuit loop, try increasing the current a little at a time but I suggest not exceeding 1A for safety and keep an eye out for any component in series with the short circuit loop that is getting too hot due to excessive current passing through it.
If your power supply folds back in the face of a short circuit across its output, you can try placing a power resistor of a few ohms in series with the supply to the damaged core. A 21W car light bulb is also a good choice in the absence of a resistor. It will light weakly at 5V and is capable of permitting a decent current draw in the damaged PCB.
Food for thought
If you can find the shorted component, you are able to disconnect its input pin and repeat a power on test to see if any more short circuits exist on the PCB.
Fraser