There is always a warning that goes along with this - on any equipment. In my setup, I actually use a Variac [I use a linear power supply - not a smps], voltmeter to monitor the output voltage, a current meter to monitor the current drain on the power supply and there's a mosfet switch to pulse the current if I need to minimize problems. Again when working with any equipment, you're expected to be aware of the situation. eg: be prepared to shut it off. And there are always a series of steps in the process.
It also depends on what kind of short is present. As I mentioned in my steps, you like to check for shorted tantalums first, since they are normally a dead short, practically zero ohms. You never want to use that old school method on that - where you apply the larger power supply. Besides even a larger power supply will crowbar [or blow a fuse] with zero ohms. So you have to painstakingly remove and check each tantalum cap.
When a component is shorted across the rails, ie: Vcc[or Vdd] to Gnd[or Vee, Vss], it is typically a couple of ohms -- that's the primary indication - as any silicon chip always has some residual resistance after a failure. If it were zero ohms, then I suggest you look much closer, because I guarantee you there will be a burned hole in the component - and so your repair is solved. So the effective current would be well within safe boundaries - since the power traces are thicker than the signal traces -- there again, if they followed proper PCB design guidelines. At 5V, with a shorted component of a few ohms, you facing less than 5A peak current.
What I didn't mention, since the power rails were shorted here, in case of shorted signal, you never want to use that old school method. Because of the fact that signal traces are normally thin and are prone to damage. Here again, there's a tried and true old school method of finding those type of shorts - using a simple ohm meter. Now on a old piece of equipment you like to stop and think, how can two completely different signals can be shorted together. If it were a brand new circuit board which came out of a production facility, well, it's obvious, there's a solder short somewhere on it - the most typical problem. Well, maybe here on your old equipment, someone was working on it before you got your hands on it. So it could be that they created a new problem when trying to fix the last problem - a inconspicuous solder short. There is also another common problem, the same chip can have an internal short between two different signals on the same chip. So you always check all the pins on that chip first.
Now, this other method is done using a metal brush as wide as a broom connected to one end of your meter probe - depending on the size of your board of course. When you're working on boards which plug into a mainframe, then you can realize how big they get - bigger than my butt - which is where the broom becomes handy. One can be made from a nice piece of 30A power cord - stripe the ends at least 6in and unbraid each conductor into a wide broom shape, with all three wires [or 4] connected at the end to your meter probe. With the other meter probe connected to the first signal pin, you simply wipe across the bottom of the circuit board to find the section with the shorted signal. Thereafter, you can narrow the search area with a smaller brush until you find the shorted signal pin.
For those types of shorts, there is also a more elaborate method of using a milli-ohm meter, *if* you have one. And there's even a much more elaborate method using a different setup with the millivolt method by injecting a small current into the trace.
If the signal pin is shorted to Ground[or Vcc] then you don't need this broom method, most often it will be a shorted output signal pin or even a shorted input signal pin [that happens]. Lifting one of the pins at a time will isolate that problem. Now in case of the processor bus signal which is connected to multiple tristate signals across several chips, eg: a databus signal, requires different steps. As it becomes an arduous task to lift that many pins. You like to have an another piece of test equipment in this case. A Current probe, sized for components - not the large variety used for motors - one such kind is the HP547A. A newer type is the AIM/TTI I-Prober 520. They even make SMT sized current probes these days[$$$]. Again it's ohm's law, the tristate signal pin on the processor bus which is shorted will drain the most current. The current probe will detect this, the probe tip is small enough to place near the signal pin of the chip to get a readout. Checking each pin on the tristate processor bus you will eventually come across the shorted signal draining the most current.
Dan