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6

Parts List - KBD-5 Keyboard 

Resistors 

R1 

680K ohm 1/4 watt resistor 

R2 

100K ohm 1/4 watt resistor 

R3 

150K ohm 1/4 watt resistor 

R4 

47K ohm 1/4 watt resistor 

R5 

10K ohm 1/4 watt resistor 

R6 

680 ohm 1/4 watt resistor 

R7 

330 ohm 1/4 watt resistor 

Capacitors 

C1, C5 

0.01 mfd disc capacitor 

C2 

47 pf polystyrene capacitor 

C3, C4 

0.1 mfd @16 volt disc capacitor 

C6 

0.47 mfd tantalum capacitor 

C7 

220 mfd @6.3 volt electrolytic 
capacitor 

Semiconductors 

ICI 

2376 Keyboard Encoder (MOS) 

IC2 

74LS00 quad NAND gate 

IC3 555 

timer 

Q1 

2N5210 NPN silicon transistor 

Dl - D3 

1N4148/1N914 silicon diode 

Misc. 

J1 

15 pin Molex edge connector 

S1-S2 

Keyboard switch, SPST locking 

S3-S56 Keyboard 

switch 

 

 

PC board, programming jumpers (2), 
Keytops 

 

Summary of Contents for ASCII

Page 1: ...1 KEYBOARD and ENCODER 219 W Rhapsody San Antonio Texas 78216 ...

Page 2: ...ls coming into contact with the leads through a 1M ohm 1 4 watt resistor supplied with the kit The ground must be an earth ground such as a water pipe and not the circuit board ground As for the connection to your body attach a clip lead to your watch or metal ID bracelet Make absolutely sure you have the 1M ohm resistor connected between you and the earth ground otherwise you will be creating a d...

Page 3: ...ou are ready to install the programming strips on the bottom of the board These strips mount vertically at right angles to the main board The etched finger connection points on the programming strips will match the connection pads on the main board when the strips are in the correct position Hold one of the strips in the correct position and turn it so that the connection fingers match the pads on...

Page 4: ...tions of your CT 1024 if a serial interface is installed Connect R to JS 1 pin 5 T to JS 1 pin 4 and E to JS 1 pin 8 of the serial interface Checkout The only equipment needed to check the operation of your keyboard is a DC milliammeter and a DC voltmeter Apply 5 volts ground and 12 volts to the proper pins and check for currents of about 4 mA on the 12 line and about 8mA on the 5 line no keys pre...

Page 5: ...closure bounce or noise and makes sure the key is firmly down and not just brushed on the way by After the delay time an output keypressed strobe is made available This tells whatever you attach to your keyboard that the code is ready for use and valid If a key is released the scanning action starts up again and goes on till a new key is pressed If two keys are pressed at nearly the same time the ...

Page 6: ...nd for solder bridges or cold solder joints Also be sure that the correct jumpers are in place Next check each keyswitch with an ohmmeter to be sure none are shorted If you have an oscilloscope apply power to the keyboard and check for a 50 KHz signal on pin 40 of IC 1 If you obtain no signal check for 5 volts on pin 1 12 on pin 18 and ground on pin 17 Repair Procedure Repairs will be made on a ba...

Page 7: ... C1 C5 0 01 mfd disc capacitor C2 47 pf polystyrene capacitor C3 C4 0 1 mfd 16 volt disc capacitor C6 0 47 mfd tantalum capacitor C7 220 mfd 6 3 volt electrolytic capacitor Semiconductors ICI 2376 Keyboard Encoder MOS IC2 74LS00 quad NAND gate IC3 555 timer Q1 2N5210 NPN silicon transistor Dl D3 1N4148 1N914 silicon diode Misc J1 15 pin Molex edge connector S1 S2 Keyboard switch SPST locking S3 S5...

Page 8: ...characters for the UPPER CASE mode AY 5 2376 Keyboard Encoder BIT NUMBERS b7 b6 b5 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 b7 b6 b5 b4 b3 b2 b1 COLUMN ROW 0 1 2 3 4 5 6 7 0 0 0 0 0 NUL DLE SP 0 P 0 0 0 1 1 SOH DC1 1 A Q a q 0 0 1 0 2 STX DC2 2 B R b r 0 0 1 1 3 ETX DC3 3 C S c s 0 1 0 0 4 EOT DC4 4 D T d t 0 1 0 1 5 ENQ NAK 5 E U e u 0 1 1 0 6 ACK SYN 6 F V f v 0 1 1 1 7 BEL ETB 7 G W g w ...

Page 9: ...M US m g t 5 Y4 SHIFT EOT US M G T 27 CONTROL EOT CR US NUL CR BEL DC NUL NORMAL ENQ NAK BS n f r 4 Y5 SHIFT ENQ NAK BS N F R 26 CONTROL ENQ NAK NUL BS SO ACK DC NUL NORMAL ACK SYN b d e 3 Y6 SHIFT ACK SYN B D E 25 CONTROL ACK SYN NUL ESC STX EDT ENQ NUL NORMAL BEL ETB v s w 2 Y7 SHIFT BEL ETB V S W 24 CONTROL BEL ETB NUL GS SYN DC ETB NUL NORMAL DC1 CAN SP CR c a q 1 Y8 SHIFT DC1 CAN SP CR C A Q ...

Page 10: ...9 ...

Page 11: ...10 ...

Page 12: ...per the right trace around the switch Connect a wire from the left pin of the key switch to Y9 IC1 pin 22 Connect a wire from the other pin of the key switch to X0 IC1 pin 39 When the shift key is held down the P key will send an Underscore To generate an under score _ you can change the function of the letter O key Isolate both pins of the O key switch Cut the trace on the vertical strip near the...

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