Assembly, Packaging and Installation (3) Tilt the upper case slightly forward and ease the bottom edge of the black front bezel gently over the floppy disc locking lever which should be in the horozontal position. (4) Manoeuvure the bottom front edge of the upper unit until it begins to mate with the lower case. (5) Keep the front mated and start to close the UPPER case whilst at the same time flexing it's side which will allow it to clip into the LOWER case. (6) Clip the rear interconnection panel into the upper case. (7) Fasten the unit together with the rear plastic clips and seal the unit by replacing the metal safety clips together with their Phillips headed screws.
(8) Check that the fan works. 2.4 Removing and installing assemblies DISCONNECT THE ACW FROM THE MAINS POWER SUPPLY. WARNING The DC power supply is connected to the PCB boards using Faston connectors and identical posts are used for the positive and the 0V supply. All Faston connectors must therefore be checked for correct polarity connection before the DC power is supplied to the various PCBs. The wires are colour coded as follows: RED +5V BLACK 0V PURPLE —5V ORANGE +12V The RED/BLUE pair provides a nominal 12V for the lower cooling fan. 2.4.1 The power supply Remove the upper case as detailed in section 2.3.2 Unplug the 11-wire Molex DC connector and the 2-wire Molex 240V connector.
While supporting the PSU, remove the four countersunk Philips screws securing it the the cradle. Take care to avoid skin contact with the heat conducting compound between the PSU and chassis. Installation is in reverse order, and a new supply of heating compound should be liberally applied to entire surface of the power supply unit where it attaches to the VDU cradle. 2.4.2 Colour monitor CRT BEWARE — IMPLOSION HAZARD — HIGH VOLTAGES REMAIN EVEN AFTER MAINS DISCONNECTION CRT replacement should only be undertaken as a bench repair and whilst exercising extreme caution. If possible, enlist the help of a second person when unscrewing the CRT from the cradle.
Proceed strictly in the order given, and refer to Figures 2.4.2 (a) and (b). (1) Remove the upper case as detailed in section 2.3.2, Leave the cradle in the normal operating position. (2) Disconnect the EHT connector on the left hand side of the CRT. WARNING DO NOT TOUCH THE CENTRE CLIP ACW SERVICE MANUAL Issue 1 17