The pinout of the clock chip obtained from the schematics is as follows: 1 16 GND 2 15 +5V 3 14 Crystal In GND 4 13 Crystal Out 5 12 +5V Dot Clock 6 11 Enable PAL 7 10 Color Clock 8 9 GND The pinout from the Commodore specifications from http://highgate.comm.sfu.ca/~rcini/classiccmp/pdf/ds_8701.pdf is: N/C 1 16 N/C VSS 2 15 VCC N/C 3 14 Crystal In N/C 4 13 Crystal Out -Reset 5 12 VCC Dot Clock 6 11 N/C Enable PAL 7 10 N/C Color Clock 8 9 VSS Note the differences on pins 4 and 5. My experiments on the chip reveal the following, which are not entirely consistent with the Commodore specifications: 1. If you disconnect pin 12, the entire chip is dead. If you disconnect pin 15, the crystal stops oscillating and all outputs stay at a constant level, but the chip is not dead. Therefore, pin 12 is the true Vcc and pin 15 is the +5V level for the crystal. 2. If you disconnect pin 9, all functions on the chip stop. If you disconnect pin 2, the outputs stop, but the crystal still oscillates. If you disconnect pin 4, an output appears on pin 11. Therefore, pin 9 is the true Vss, pin 2 is the output enable, and pin 4 is the enable for pin 11. 3. If you ground pin 5 (-Reset), the dot clock stops, but not the crystal. 4. Pin 10 maintains a constant output at +5V. 5. I have found no functions for pins 1, 3 and 16. If you incorporate all this information into a pinout, it would look like the following: N/C 1 16 N/C Output Enable 2 15 +5V for Crystal N/C 3 14 Crystal In Disable pin 11 4 13 Crystal Out - Reset 5 12 Vcc Dot Clock 6 11 Unknown Output Enable PAL 7 10 +5V Constant Output Color Clock 8 9 Vss Enable or disable is accomplished by tying to ground.