Help needed with HP-IL disk drive

[Paul Berger (Canada)]

Well there is nothing special about the power supplies I use, but unfortunately they where purchased from a now defunct chain of stores in Canada. I am sure that any sort of universal supply that can output 6V at about 2A will be fine.

What I did for mine is I made up pigtails with female spade connectors on one end that I slip over the battery contact, don't worry if they are not the same width as long as they stay on the terminals, and on the other end I have a connector that I plug the power supply into. You could also put the spade connectors right on the ends of the leads from the power supply too, just be careful of the polarity.

I don't think that the power supply is critical except it needs to supply 6V , I have never checked to see exactly how much current they draw the two that I have successfully use one is a fixed voltage 6V supply rated at 1.8A and the other is an adjustable 2A supply that has a switch to select a few different outputs from 6-12V, both of these work fine.

The problem with a bad battery pack is the 6V nominal voltage from the batteries feeds a 3 terminal 5V regulator that supplies the logic voltage and with only 6V in it is pretty close to the drop out voltage for the regulator, the spec sheet for it says it will operate with a minimum of 0.6V difference which means that below 5.6V it will stop operating. These battery packs are reputed to use lead-acid gel cells and it is possible to get new cells to replace the ones in the pack, but if it still has the original cells they would likely be very old and long past their expected life time.

The most common problems with these units are the diskette drives themselves, however the B version is a little better than the A in that respect. Of the four non-working units I bought only one had a legitimate electronic problem, and that did not affect the HPIL.