I have a Dell D750P-s0 switching power supply that I want. To use to power my ichar f er. How do I find out what is the positive and whicb is the negative outputs? There are no posts ormarkings only tabs feom the board

It's a little more involved than just finding the positive and negative outputs. There are guides on-line to convert old PC power supplies to stand alone supplies (assuming that's what you have). I've done this before many years ago. I do recall reading somewhere that Dell powers supplies did/do not follow normal convention in relation to wire colours which may make things difficult if it applies in your case. Be warned, this modification may you expose to live mains power. Please be careful.

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