Figure 4-41 Unscrew The Screws On The Filter Board - Keysight 8990B Service Manual

Repair Guide 4
0515-1940
Filter board
Figure 4-41 Unscrew the screws on the filter board
11 To remove and replace the sensor adapter board, unscrew the four screws
(0515-0372) with the 5 in-lbs, T10 Torx screwdriver as shown in Figure 4-42.
Keysight 8990B Service Guide 125