I have a Dell Inspiron 620 desktop that's got me flummoxed. First, it was not powering on. After testing a few things I got a non-standard reading from a PSU tester (slow on the PG reading) and decided to try changing that.
I put in a 400 W Diablotek PSU that tested fine and works fine in other computers, but the Dell wouldn't start. I subsequently tried several other PSUs, all of which test fine, all of which power their machines fine, all at or above the 300 W rating of the original Dell adapter. None of them work.
Meanwhile, I cleaned out the one that I thought had failed (it had a lot of dust) and reconnected it (24-pin MOBO, 4-pin MOBO, sata DVD and sata HD) and lo and behold it starts. But when I try any of the other PSUs, they still do not start (no partial start, no fan, nothing).
The original PSU looks standard to my eye, the only difference I see is that the 4-pin power connector is 2 brown and 2 black instead of most of the others which are 2 yellow and 2 black. Is that a meaningful distinction that's preventing any replacement PSU from starting the machine? Any insights would be greatly appreciated. Thanks!