Assembly; Board (Optional); Fdc Board (Optional); Cpu Board - Radio Shack TRS-80 Model 4 Technical Reference Manual

2.2 Assembly

2.2.1 RS-232 Board (optional)
1. Install the PC Board using #6 x 1/4" screws. If
applicable, press the PC Board onto the plastic
spacer mounts then fasten with the screws.
2. Reconnect all cables to the RS-232 Board.
2.2.2

FDC Board (optional)

1. Install the PC Board using #6 x 1/4" screws and
the plastic spacer mounts, if used.
2. Reconnect all cables to the FDC Board.
2.2.3

CPU Board

1. Make sure good insulating washers are attached
to the CPU Board then fasten the Board using #6
x 1/2" screws,
2. Reconnect all cables to the CPU Board (power
supply cable, video, keyboard, and cassette
cables, and if applicable, RS-232 sound board,
and FDC inter-connect cables),
3. Attach the small PCB Mount Bracket (if used) to
the metal chassis bracket with two #6 x 1/4"
screws.
2.2.4

Power Supply

1. Fasten the Power Supply to the CPU chassis
bracket using #6 x 1/4" screws. Be sure the
ground tab is fastened back in place.
2. Reconnect all cables (power supply, video,
keyboard, and cassette cables, and RS-232 and
FDC power cables and Disk ribbon cable if
necessary).
2.2.5

Disk Drive (optional)

1. Place the Disk Drive in the bottom position and
reconnect the ground wire and power supply
connector.
2. Fasten the Drive with four #6-32 x 1/2" screws
and four flat washers (two on each side).
3. Reconnect the FDC inter-connect cable to the
rear of the Drive.
4. Position the second Disk Drive in the top position
and reconnect the ground wire and power supply
connector.
5. Fasten with four screws and washers (two on
each side).
6. Reconnect the FDC inter-connect cable to the
rear of the Drive.
2.2.6

Disk Drive Power Supply (optional)

1. Before installing the Power Supply be sure that
the bottom Disk Drive is mounted in place and
the Disk Shield is in position on the Disk
Mounting Bracket.
2. Reconnect all cables and wires to the Power
Supply.
3. Fasten the Power Supply with four #6 x 3/8"
screws. Be sure the ground tab is fastened back
in place.
2.2.7

Video Monitor (CRT) and Video Board

1. Position the CRT in the Case Top and install the
upper left and lower right #10 washers and nuts.
2. Install the upper right and lower left #10 washers
and nuts. Be sure to reconnect the ground wire
from the CPU cable. It will require two nuts to
fasten it.
3. Install the Video Board into the Case and fasten
with two #6 x 3/8" screws.
4. Connect the ground wire with solder lug back to
the Video Board.
5. Install the plug on the rear of the CRT neck.
6. Install the four color coded wires with spade lugs
to their associated terminals (as determined by a
colored dot on the yoke near each terminal).
7. Install the high-voltage anode wire on the side of
the CRT. Use a screwdriver to compress the clip
and insert it into the CRT. Press down on the
suction cup to secure.
2.2.8

Case

1. 1, Double-check to be sure all wires are
connected correctly and all Boards are properly
fastened.
2. Attach the chassis shield (if used) with #6 x 1/4"
screws and reconnect the ground connectors.
3. Carefully place the Case Top over the Case
Bottom. Do not hit the CRT neck. It could implode
or break off.
4. Install the #6 x 3/8" sheet metal screw and flat
washer in the top rear panel of the Case.
5. Carefully rest the Computer on its rear panel and
replace the ten #8 screws; five 1" sheet metal
toward rear, three 7/8" machine head along front,
and two 1" machine head in remaining positions.
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