User guide

4
2-14 Disconnect the two 14-pin DIP ribbon cable connectors from the motherboard
sockets by spreading the retainer clips and pulling the DIP connectors free.
Disconnect the 50-pin ribbon cable connector from the top edge of the A1A1
keyboard.
2-15 Set the front panel assembly aside.
2-16 NOTE: The following steps refer to the A1A4 and A1A5 video driver boards. On
some later model systems, a single board replaces the A1A2, A1A4, and A1A5
boards. This board does not change the circuit layout of the three circuits and the
A1A4 and A1A5 circuits can be easily identified as if they were separate boards.
2-17 Remove the A1A4 board ( 8566/67/68 service manual for circuit board and
component locations).
2-18 Replace A1A4R43 with an 8.25K resistor from the kit and reinstall the A1A4
board.
2-19 Remove the A1A5 board.
2-20 Replace A1A5R43 with a 6.49K resistor from the kit and reinstall the A1A5
board.
2-21 NOTE: Changing resistors on the A1A4 and A1A5 boards preserves the correct
X and Y display output amplitude to the rear panel.
2-22 Warning! Potentially Lethal Voltages Present!
2-23 Review the 8566/67/68 service manual for; safety guidelines, CRT warnings,
and high voltage power supply warnings before proceeding.
2-24 Carefully discharge the CRT and high voltage power supply.
2-25 Disconnect and remove the CRT as per the 8566/67/68 service manual.
2-26 Remove the rear CRT mount entirely rather than just loosening it.
2-27 Remove three top covers: the A1A3 shielding cage cover, the A1A6/A7/A8 cage
cover, and the A1C3 capacitor cover. Lay them aside to be reinstalled later.
2-28 Remove the A1A3 high voltage power supply and shielding cage.
2-29 Separate the high voltage power supply from the shielding cage.
2-30 Set the A1A3 shielding cage aside for later installation.
2-31 Disconnect the ends of the three SMB cables that are connected to the top of the
A3 card cage.
2-32 Remove the top cover of the A3 card cage.
2-33 Remove all the A3 cards from the A3 card cage.
2-34 Remove the A3 card cage.