Upgrading HP Pavilion desktop TP01 power supply

[JonGleissman]

I was reading previous questions from people asking about upgrading or replacing the power supply unit (PSU) as the stock one is pretty low power, and after adding a beefy video card I thought it would be good to upgrade.

My experience is that I actually had quite a few older spare (older) PSU laying around, some were third party units, others were from other PC manufacturers. The slightly tricky part was that none of them had exactly matching connectors for the Pavilion, as HP use their own non-standard connector to control the PSU (connection is marked as "P2 PWRCMD" on mainboard and it's a small 7 pin mini-connector, and you won't really find a matching connector like this on other non-HP PSU) but anyway I came across a video (see reference at end of post) which showed how to do it but I modified it slightly and got mine working fine. It's a cheap and easy hack. I've done it now successfully twice with 2 different PSU (one of them blew a capacitor after a year and failed, not through my or the HP's fault, it was just old) and so I thought I'd share my learnings.

For those that might not know, PSU are smart these days, you can't just plug in a PSU like back in the in the 90s and it will simply pump power to the mainboard. No, the mainboard needs will communicate to the PSU and tell it that it's OK to go and to turn on the power, once it's done that then the PSU will send over the power, and your PC will start.

So on the Pavilion mainboard there are 2 power input connectors, both are ATX 4 pin (basically it forms a 2x2 square with the pins) this supplies 12V and ground to the mainboard. 2 wires are yellow (or yellow/blue sometimes) this is the 12V and the other 2 wires are black (ground). So you'll need to find a PSU that has these two. Make sure that the 2 yellow wires are on the side of the plug that has the locking catch. Don't use plugs where the black wires are on the side of the locking catch -  this is not suitable and may damage your mainboard. Again, you need to have the 2 yellow wires on the locking catch side, and the 2 black wires are on the opposite side.

Now what if your PSU only has one ATX 4 pin plug (or none)? Have a look on your PSU and you may find there is one or more ATX 6 or 8 pin plug (which have yellow wires and black wires), this can be used, as it should still plug in fine (with the spares pins just hanging off). Just make sure that the yellow wires are both on the locking catch side of the plug and the black wires are on the other side. 

OK now that's sorted, you need to fix up the power control command plug. It's actually pretty simple. But you'll need to cut wires and join them (i.e. solder). So cut the 7 pin plug off (don't cut it right at the plug, give yourself a few inches as you'll need some spare length to connecting/soldering this to the PSU controller). You should only have 3 wires coming out of this plug, starting at one end it should be BLACK, then the next pin is empty, then GRAY, then GREEN, and then the other 3 pins have no wires.

Now on your new/spare PSU you're looking for a ATX 20 or 24 pin connectors (2x10 pin or 2x12 pin shape), this is a very common mainboard connector and most PSU will have this. Find the purple wire, there's only one (we're not going to use it ) but next to it is a GRAY and BLACK - we want these 2 wires so cut them off from the ATX connector (you could use any of the BLACK wires if you wanted as they are all common). Now find the GREEN wire (again there's only one of these) and also cut it away from the ATX connector.

The GRAY wire is PWR-OK signal,  BLACK is ground/common, and the GREEN is PS-ON (power supply ON).

Now connect the GRAY wire from the PSU to the GRAY wire of the plug. Then join the GREEN and BLACK wire from the PSU together (that's right) and also join the GREEN and BLACK from the plug together and then connect them - that's right they are all common. Once all connected up, good luck, it should work.

The only downside is that for some setups, after you've turned off your PC, the PSU fan may continue to run, or your PC cooling fan or video card fan will stay running. In the original video they put an extra switch in, but I couldn't be bothered. I just turn my PC's power off at the power multiboard it's plugged into, or pull the cord out of the wall.

Credit: Original video linked below or if not, search on YouTube for "How to replace HP power supply with standard ATX PSU (PWRCMD + 2x 4-pin)" by "FixAndTech"