DEC AlphaServer 1000A Owner's Manual page 190

Figure 9-7 shows the default settings for jumpers on the CPU card.
The J1 jumper on the CPU card activates the SROM tests and the fail-safe loader.
The J3 and J4 jumper settings affect clock speed and other critical settings for the
AlphaServer 1000A system. The J3 and J4 settings differ according to model.
Figure 9-7 CPU Card Jumper Positions for Normal Operation
Model 4/266
9-14 Quick Reference
J1
0
1
2
3
4
5
6
7
MA00926
J4
J3
MA00951
AlphaServer 1000A Owner's Guide