– 10 –
DISASSEMBLY
1.
Unplug the units from the AC wall outlet
and disconnect all cables from the rear
panel.
2.
Turn the computer over and remove the
four screws from the case bottom. One of
the screws is located under the warranty
seal in the upper right corner of the case
bottom.
3.
Turn the computer right side up. Discon-
nect the snap locks located on the right and
left side of the case by placing a slotted
screw driver in the groove between the top
and bottom cases, approximately 2.7
inches from the rear of case. Push in and
turn the screwdriver to pop the case apart.
4.
Disconnect Keyboard cable from wire con-
nector. NOTE: Pull flat wire upward.
5.
Remove three screws that fasten the PC
Board to the bottom of the case. Remove
the PC Board.
6.
Use tweezers to remove eleven clips that
fasten the bottom shield to the P.C. Board.
7.
Locate the eight positions where the top
shield is soldered to the PC Board. Remove
this solder with solder wick or a desolder-
ing tool. Bend the protruding edge of the
shield upward until it is parallel to the slot
and remove top shield.
REASSEMBLY
1.
Install the top PC Board shield. Solder the
shield to the ground plane at eight points.
2.
Install the bottom shield with metal side up.
Secure to the PC Board with eleven clips.
3.
Install PC Board in bottom of case. Secure
with three screws.
4.
Install the two keyboard cables in their
respective connectors. This will be easier if
both hands are used and you are facing
rear of unit. Refasten cable restraints.
5.
Join the top and bottom cases and push
them together at the snap lock positions.
This is a tight fit, therefore repositioning of
the cases may be required.
6.
Install four screws in bottom of case.
1.
Removal of Top Cabinet
Remove 4 screws as shown in Figure A.
Figure A
2.
Removal of P.C. Board
Remove flat wires of keyboard from con-
nector.
Remove 3 screws as shown in Figure B.
Figure B
3.
Removal of Keyboard
Remove 4 screws as shown in Figure C.
Figure C
Содержание TRS-80
Страница 3: ...3 SECTION I SYSTEM DESCRIPTION...
Страница 5: ...5 SYSTEM BLOCK DIAGRAM...
Страница 7: ...7 SECTION II SPECIFICATIONS...
Страница 9: ...9 SECTION III DISASSEMBLY REASSEMBLY...
Страница 11: ...11 SECTION IV THEORY OF OPERATION...
Страница 21: ...21 SECTION V TROUBLESHOOTING...
Страница 25: ...25 SECTION VI PARTS LIST...
Страница 30: ...30 SECTION VII PRINTED CIRCUIT BOARDS...
Страница 31: ...31 MAIN P C B TOP VIEW...
Страница 32: ...32 BOTTOM VIEW...
Страница 33: ...33 SECTION VIII IC INTERNAL CONNECTIONS...
Страница 34: ...34 IC INTERNAL CONNECTIONS U1 MC6803G Motorola or HD6803P Hitachi...
Страница 35: ...35 U11 MC6847P Motorola...
Страница 36: ...36 U2 SN74LS373N Motorola or MB74LS373M Fujitsu U7 SN74LS245N Motorola or MB74LS245M Fujitsu...
Страница 37: ...37 U3 MB8364M Fujitsu U9 10 PD4016C 1 NEC or PD4016D 1 NEC or MB8128 15P Fujitsu or MSM2128 20RS Oki...
Страница 41: ...41 U15 LM339N Motorola or PC339C NEC U18 SN74LS74AN Motorola or MB74LS74AM Fujitsu or HD74LS74AP Hitachi...
Страница 42: ...42 U16 MC1741CP1 Motorola or HA17741PS Hitachi U17 MC7805CT Motorola or NJM7805A JRC or PC7805H NEC...
Страница 43: ...43 SECTION IX SCHEMATlC DlAGRAM SECTION X EXPLODED VlEW...