Appendix C. Changing RAM or PROM Chips in the CR10

C.3 Installing New PROM

The PROM chip is found at location C8 on the CR10 CPU board, (see Figure C-2). With a small flat screw driver, gently pry out the PROM chip and replace it with the new one. The new chip should be installed so that the notched end is towards the nearest card edge. Before pushing the chip into the socket make certain that all the pins are seating correctly. After installing the chip, check for pins that may be bent or not making contact. If you notice a bent pin, remove the chip, carefully straighten it and repeat the installation procedure.

To make certain that the new chip is installed correctly enter the CR10 *B mode (Section 1.6 in the CR10 Operator's Manual) and advance to the second window. This window displays the PROM signature. The five digit number in the window should match the PROM signature given with the new PROM documentation. If the numbers are different, disassemble the CR10 and look for pins that are bent or not firmly seated.

FIGURE C-1. Disassembling CR10

C-2