I love older radio's and the service manuals that are sometimes hard to find. Was able to find a manual quite easily on this site.
Text excerpt from page 11 (click to view)
4. Amount of change of jitter
The amount of change of jitter is displayed in the focus bias check mode. The displayed value has 256 steps from 00 to FF. Example: focus bias (FB) Adjustment value�00 Jitter value�FD
RNDM
RESUME 1 DSL
Tracking offset
Adjustment value
* Adjustment values and jitter values are indicated in hexadecimal.