[aprssig] TNC-220 battery life mod?

[Dave Baxter]

Morning All (well it is here...)

Does anyone have details on record of the modification to the PacCom
TNC-220, and it's SRAM backup system, to improve the battery life?  

I vaguely remember something about a better choice of resistor values,
select line driver chip type, minor wiring change and so on that
drastically reduced the battery drain current when the TNC was not
powered up, not exactly sure any more.

I remember there it was much talked about some years ago, but I can not
find either my notes of the time (two house moves back) or any reference
to it on the net.

73 & TIA

Dave G0WBX.