New heating bed problems !

I don't think 120 watts is enough, that's only 10 amps at 12 volts. I think that's what the stock supply was and that's just enough to get by. If your new heater needs more power than the original your going to need a bigger supply. When my stock supply started to die I replaced it with one of these:

http://www.amazon.com/SUPERNIGHT-Switch … wer+supply

That's a 30 amp 360 watt supply for less than $30. So far so good. I've only added a couple of extra fans so far, but I've got plenty of watts to spare for future upgrades ;-)

TiM

Yup, into the PCB power input terminals, same as the old supply.

Currently, red wire should go to + and the black wire goes to -, right?

For the new supply, you'll need to make up your own wires to go between. Connect something from any of the "+V" terminals on the new supply (they're all connected to the same thing) to the + input of the PCB, and one of the "-V" terminals to the - input of the PCB.

You could hack some of the wire off the old PSU, or use wire out of an old extension cord, or buy some by the m/ft from an electronics store (get the largest multi-stranded single-core cable that will fit into the PCB screw terminals).

Um, my bad, you're fine... I forgot to ask: some SD boards have screw terminals for power, but I think the newer ones have a barrel-type DC power connector. Does your power supply connection use one of these?

If you do you can either:
(a) Sacrifice the old power supply by chopping off and reusing the cable and connector,
(b) Going to the internet or an electronics store and buying a new connector and some cable to solder up a new one, or
(c) Avoid soldering by buying an adapter on the net that has screw terminals, like this:

I'll confirm the exact sizes of everything when I get a chance.

Although the wiki talks about screw terminals too, it may be of help, especially with the wall power wiring.
http://www.soliwiki.com/Upgrade_The_Power_Supply

Yup. Checked mine last night, +12V (+V on your new PSU) to the center and GND (-V on your new PSU) to the barrel.
Yellow tip means it's an EIAJ connector, so the generic 5.5mm barrel connectors may not sit nicely. I would highly recommend reusing the existing cable and connector as zipperboy has done, unless you can ensure an exact match.
The bare copper inside the cable is normally -ve and the insulated cable (whatever colour) +ve, but again make sure you confirm before plugging it back in!

That sounds concerning - overload/short protection. Did you confirm that the positive is connected to the center of the barrel connector and the negative on the outside of the barrel before plugging it in?

My condolences... *sigh* I feel partly responsible here, even though I did ask you to:

I too get excited and jump straight in sometimes; I have a cooked raspberry pi on my pinboard glaring at me with a note underneath saying "measure twice, plug once" for this very reason! (he suffered 12V instead of 5V, it was really quite embarrassing)

If you haven't got a multimeter, you need one. They're awesome, and not expensive. Nearly any one will do. Borrow one from a friend, local electronics shop, sometimes even the hardware store. Failing that eBay has millions. Probably quite literally.

Armed with that, check what's gone on in that cable, and if the voltage is indeed back-to-front, then yeah, you're pretty much definitely going to need a new board... SD will sell you a stock one, or post on this forum to see if anyone wants rid of theirs - a few people have changed to other boards, and might have a functional one gathering dust... Worth a shot I suppose!

Please don't be disheartened, you win some and you lose some.