Kluges required for rev. 1 boards

Rev. 1 of the SURF board requires a number of kluges to work:

• Some series resistors in the CMOS module communications lines need to be jumpered. These resistors are R2, R4, R114, R115, R211, R210, R309, R310, R409 and R423.
• On the LVDS receiver chips the enable pin (pin 16) needs to be tied to high. Note that the orientation of the LVDS receiver bypass cap (good place to get Vcc) is reversed on channel 0!
• The AD5242 chips need the SHDN# pin tied to power, not ground. Lift pin 6 and connect to pin 5.
• Use the LT1713 instead of AD8561 comparator (U100, U200, U300 and U404); also lift pin 2 of the 1713 and bridge a 10k resistor between pin 2 and the end of R102/R206/R305/R405 that's adjacent to pin 3 of the 1713.
• Don't load R100, R111, R202, R221, R302, R321, R402 and R420.

Fig. 2.3 shows where on the board these changes need to be made.

Figure 2.3: Locations of the most invasive kluges required on the SURF board. Refer to Sec. 2.4 for explanation.