A couple days ago I posted on here asking for help about an ATX power supply. I got great help, and ended up buying it. However, now I’m having problems with the wiring. No matter what arrangement I try, my printer refuses to turn on. I know my jumper cable is correct because my power supply turns on with it connected. Here’re some pictures of my wiring; what am I doing wrong? I suspect I need to jump the empty ports in the board connector to the cables directly beside them (not to each other), but whenever I try it it doesn’t work. How should it be wired? Thanks!
Want happens when you skip the y- cable and plug the 4pin connector directly to the board? Have you tried putting a load on the 5V? Older PSUs needed that.
Does your printer have a heated bed? Are you sure the polarity is correct?
As Tom said many power supplies will “crowbar” if there is no load on the 5V output.
Is the power_on cable already correct connected?
I have the Rev.D board, yours appears to be the Rev.F. The Rev.D has a four pin power harness, your Rev.F seems to have a six pin power harness. Using this guide http://help.printrbot.com/Guide/Installing+Simple+Metal+Heat+Bed+Upgrade/147 in step 18 it says you need to connect the six pin ATX connector from the ATX PSU. I don’t think you even need to use the Y-adapter harness.
And @Matt_Olsen has a point, check which rev printrboard you are running. Rev F needs a 6 pin connector.
@Tom_Georgoulias @Jimmy_Edwards Nothing changes when I plug the 4 pin cord directly into the board. I put an LED on too, but that didn’t change anything.
@Stephanie_A Yes, it does. And yes, the polarity appears to be correct. Red wire to the outside of the 'bot.
@Erich_HaHaOh Yep. With an LED, per Tom’s and James’s suggestion. It had a normal wire before that.
@Matt_Olsen I think this is the problem. My PSU doesn’t even have a 6 pin connector.
Sorry about the Rev F and Rev D confusion; I meant to add that I had a Rev F to the description, but I guess I forgot. Once again, I guess the problem is that my PSU is without a 6 pin cable. Is there a way to adapt the current cabling, or do I have to order a new one? Thanks!
The 4 pin and 6 pin are opposite in polarity. If you plug the 4pin from an ATX into the 6 pin on the rev f, you fry the board. I fear you have blown your board.
@Brook_Drumm That nearly gave me a heart attack. Thankfully, my board appears to still be fully operational. Thank you for the warning!
@David_Aden You are going to need more of a load than just an LED. Something like this. http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply
Did you jump the green and a black? It is in our docs.
If u have a Rev f board, take off the y adapter and use the PCI-e plug instead. You’ll still need to jump the black and green wire.
@Jimmy_Edwards The power supply is turning on, and it was even before I put on the LED.
@Brook_Drumm Yes, I did. I’m sure it works, as the PSU can turn on and off without being connected to the printer.
@James_Malenko My power supply didn’t come with a 6 or 6+2 pin PCI-e plug. : /
I just wanted to be sure you were connecting polarity correctly. We may have an adapter plug or you can swap pond if they are backwards in the 4 pin. You’ll have to look at the docs- I don’t want to quote the polarity from memory 
If we can confirm its hooked up right but board doesn’t power, we can always replace w/in warrantee
@Brook_Drumm I think it works now! I switched the polarity of the Y-adapter plug and replaced the LED with a piece of wire. (Don’t know why that was necessary, but it didn’t work without it.) The first time I tried to heat the print bed, the whole thing shorted out and Repetier crashed. That only happened the first time though. The problem seems to be solved.
Thank you all very much for your help!
Awesome!
Glad to hear you got it going