Need IBM Portable 5155 power supply

How are you testing it? Most IBM PC PSUs of that period need a load before they will start up. The PSU on its own will appear to give no outputs. new Would you be interested in having a go at repairing the existing PSU. From what I remember it's a fairly conventional SMPSU, similar to the one in the PC/XT machine. You'll need bristol spline keys and tamperproof torx drivers to get inside, though, and at least a multimeter for troubleshooting (a 'scope and isolating transformer are useful!). You'll need the bristol spline keys to get the whole PSU unit out of the 5155, BTW. If you do decide to go inside, remeber there are dangerous voltages in there. Much of the circuitry is not isolated from the power line. And there are capacitors that charge up to a total of 400V (and when the unit is operational, that circuit can easily supply enough current to kill you!). Take great care if you do pull the cover. -tony