Specifications

Jumper Configurations
Table A-1
Jumper Descriptions (continued).
JUMPER # DESCRIPTION
W12 Install jumper W12 to bring battery ground
reference to the timekeeper and 32 Kbyte
RAM, and any other RAM chosen for battery
backup by jumpers W35 and W38. Remove
this jumper to erase the RAM (the RAM
drive for DOS systems) and timekeeper. For
rapid erasure of RAM and timekeeper while
W12 is removed, temporarily short the W12
pin nearest the extractor to STD bus ground
pins 3 and 4. Factory default installs W12.
Note: If the battery is not installed, ensure proper
operation of timekeeper and 32K static RAM by
installing a wire across the (+) and one of the (-)
terminals of the battery sockets, and install W12.
To clear battery-backed RAM, quickly remove
jumper W12 and tie top pin of W12 to ground pin
of pack 1B (8254 counter/timer) for a second or
two, then replace jumper W12.
W12 Function
IN † Tie the battery output to the time-
keeper and all battery-backed RAM
OUT Erase the timekeeper and all battery-
backed RAM
A-10