VDD transistor switch on programmer

[Rusttree]

I'm trying to use a transistor as a switch to turn on VDD using a parallel port pin. The circuit I've put together acts as an inverter, so when the parallel pin goes low, VDD equals the supply voltage. This is for a PIC programmer. See the attachment for my circuit.

All seems well according my voltmeter. But the PIC doesn't appear to like having VDD supplied by this circuit. If I short the VDD pin on the PIC directly to the supply voltage, everything works fine. Is there something obvious here I'm doing wrong?

-Dan

 

[AtomSoft]

are both grounds for PIC and Parallel the same? So when the Parallel PIN is HIGH this should gnd VDD pin ... and when LOW it should disconnect and use the 5v line... only issue i see is maybe you have actual transistor backwards? also ensure gnds are tied for both and that transistor is actually a NPN... you didnt state which transistor your using but by symbol its a NPN...Try that same circuit with a LED first and see if it works