Posts: 90
Threads: 2
Joined: Jan 1970
Most of us rebuild/have rebuilt these packs when the cells give up. For battery repairs please see: http://www.hpmuseum.org/repair.htm
It is possible to run the machines directly off a DC power supply.
Posts: 1,193
Threads: 43
Joined: Jul 2005
If you plan to use an external supply, keep in mind that the batteries work not only by smoothing but also by regulating the voltage. A capacitor would smooth the voltage, but since it will not regulate, the voltage will be higher than allowed !! A regulated 2.5 volt DC supply may work, connected into the batteries bay. Or a 3.2 volt DC supply, connected to the adapter pins. Please take this as a suggestion only, no warranties !! Also be careful about polarities !!