HP-110: problems with battery pack

[Gianmaria]

I recently bought on Ebay an early HP-110 laptop. I replaced old battery pack with new cells but 110 don't turn on with battery pack alone, it turn on only if wall charger is connected... I tested voltage and battery pack is fully charged. (It seems the same problem of "Classic" calculators...) Please help me... Thanks

[George]

The fuse in the battery circuit may be blown. The Question and Answer column in the Portable Times (I think that was the name of the magazine/advertisemnt circular put out by a company in the midwest who used to sell HP portables) described this problem for the Portable Plus, and the HP110 is probably similar. The fuses are soldered in on one of the Printed Wiring Boards, and look like a diode or a resistor. You may have some trouble getting an exact replacement. Look for a service manual. If I can find out the fuse value (I may be able to in a week or so) I will let you know.

[Gianmaria]

Yes, on the battery board there are two components: one it seems a diode, other seems a resistor (big red, brown, black and green)... I wil try to replace both. Thanks George!

[Joe]

If there's a fuse on the board it will probably be a Pico fuse. It will look like a resistor but usually won't have any color bands. They usually have the amp rating marked on them. It will look like "3/4A" or something like that. The HP 9114 battery circuit board uses a Pico Fuse and I replace lots of them.

I have a service manual for the 110 somewhere.

Joe