power supplies and voltage regulators

In general you cannot wire voltage regulators in parallel.

The reason is that the voltages on them are not precisely the same, so one will try to supply the entire load.

You could try isolating them with diodes, but I'm not sure that's a hugely viable option either.

The best approach is to get a higher current regulator or to make the regulator supply current via a seperate pass transistor.

There are examples of doing this in many datasheets.

Let's see if I can find one...

See page 13 of this datasheet. Note that this technique may not be generaly applicable.

As regards your regulated supply. It sounds like the full unregulated voltage is appearing at the output. If you didn't make a mistake or damage something when putting it back together, you most likely have a shorted pass element (this may be a transistor, or even a three-terminal regulator.

Without a circuit diagram or pictures and quite a bit of time, we would not be able to say a great deal more.