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- Parts list for one megabyte memory board with clock
-
- Chips
-
- 2 74LS00 B5, B6
- 2 74LS04 A6, B3
- 2 74LS10 A4, B1
- 2 74LS20 A2, A7
- 2 74LS74 A3, B4
- 1 74HC74 A8
- 1 74125 D4
- 1 74LS138 A1
- 5 74LS153 C1, C2, C3, C4, C5 (May be 74LS253)
- 1 74LS175 A5
- 2 74LS393 B2, C6
- 2 74HC244 D3, D5 (May be Am2966, NOT 74LS244)
- 3 74LS245 B8, D1, D7
- 1 MC146818 C8
- 32 Rams E1 thru H8 (May be any 256k by 1 dynamic ram at 200ns
- or faster access time. I have tried
- several brands, both CMOS and NMOS, with
- no problems.)
-
- Capacitors
-
- 48 0.1 uf ceramic cap 12v or higher (bypass caps at each chip, not on schem.
- 2 1.0 uf ceramic or tantalum, 12v or higher
- 1 10 pf NP0 ceramic or mica
- 1 4-20 pf variable (substitute any cap that covers 7-15 pf range)
-
- Diodes
-
- 5 1N4148, 1N914 or equivalent
-
- Resistors all 1/4 watt 5% film
-
- 1 560 ohm
- 1 100k
- 1 390k
- 1 22M if not available substitute 10M
-
- Crystal
-
- 32768 Hz watch crystal
-
- Battery
-
- 4 Nicad cells with holder. Either A or C size is ok.
-
- Sockets
-
- 14 14 pin wire wrap sockets. I substituted 16 pin for a price break.
- 39 16 pin wire wrap sockets.
- 5 20 pin wire wrap sockets.
- 1 24 pin .6 in spacing wire wrap socket.
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