> I attached a potentiometer between the base and +5 and turned it
> until the relay just activated, then backed it off and tried toggling
> the nStrobe line. At that point I was able to control the relay from
> the PC port, but removing the pot and measuring its value showed
> that it was 203Ohms. Not K Ohms; Ohms. That ain't going to cut it

That doesn't sound right. You might expect a current gain of 100 from
the transistor. It needs to pass about 75mA for the relay to pull in, =>
about 0.75mA into the base. Your experiment suggests more like
25mA is need (for some reason), which you won't get from a parallel
port pin. The 4k7 pullup would supply 1mA

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