Chapter 4  Retrofitting Options
To Retrofit A6 High Stability Timebase Assembly (Options 001, 010, and 
012)
4-12 Assembly-Level Service Guide
4
Procedure
1 Turn off the Counter and remove power cord.
2 Remove the cover.
See the section titled “To Remove the Cover” in Chapter 3 of this guide.
3 If you are retrofitting the Option 001 Medium Stability Timebase 
Assembly, go to step 5.
If you are retrofitting the Option 010 High Stability or Option 012 
Ultra-High Stability assembly, go to step 4 (the next step).
4 Plug the oven oscillator into the socket on A6 Timebase Support 
Board, and secure the oven oscillator to A6 using the two Pozidriv 
screws (H7) as shown in Figure 4-2.
5 Plug the oven oscillator into the socket on A6 Timebase Support 
Board, and secure the oven oscillator to A6 using the two Pozidriv 
screws (H7) as shown in Figure 4-2.
6 If you are retrofitting the Option 001 Medium Stability Timebase, 
remove the jumper cap on P1 of A6 Timebase Support Board as 
shown in Figure 4-2.
If you are retrofitting the Option 010 High Stability and Option 
012 Ultra-High Stability timebases, DO NOT remove the jumper 
cap on P1.
7 Mount A6 High Stability Timebase Assembly on the left side using 
three TORX 10 screws (H1) as shown in Figure 4-2.
8 Plug the power supply assembly’s two-wire cable into the 
three-prong connector (J2) on the high stability timebase 
assembly as shown in Figure 4-2 (if the two-wire cable exists).
9 Connect A6 High Stability Timebase Assembly cable to connector 
J9 on A1 Motherboard Assembly as shown in Figure 4-2.