Digital Alarm Clock (277-0107) Assembly Instructions Faxback Doc. # 18012 WARNING: The transformer will have 120 volts across the primary; therefore, it is very important that you insulate the completed project properly. NOTE: Solder all leads on copper side of the circuit card and clip excess wire as you perform each step. 1. Mount 10K 1/2 watt resistors R-1, R-3 through R-10 and R-25. 2. Mount 100 ohm 1/2 watt resistors R-11 through R-18. 3. Install the 15K 1/2 watt resistor R-20. 4. Install 680 ohm 1/2 watt resistors R-2, R-22 through R-24, R-26 and R-27. 5. Install the photocell, R-21. It can be mounted externally or on the clock circuit card, depending upon the enclosure, or case, that you may wish to use. 6. Mount silicon rectifiers CR-1 through CR-5. Be careful to install each rectifier in the proper direction. (CR-1 and CR-2 - cathode pointing toward center of the board(>|), CR-3, CR-4 and CR-5 cathode pointing outward (|<). 7. Install the 200 microF electrolytic capacitor, C1. Observe polarity ( + and -). 8. Install the 5000 pF disc capacitor, C-2. 9. Mount PNP transistors RS2024 Q-1 through Q-6. Note: Q-1 and Q-2 are necessary only if a "SECONDS" display feature is desired. 10. Mount NPN transistors RS2014 Q-7 through Q-21. Note: Q-7 and Q-8 are also necessary only if a "SECONDS" display feature is desired. 11. If you desire a "wake up" alarm, install the 100 ohm 1/2 watt resistor, R-19. 12. Install the transformer, T-1. It is critically important that the transformer be mounted correctly, see Figure 1. 13. Connect the line cord to the 120 VAC terminals. IMPORTANT: Before performing step 15, note the location of the "dot" on the circuit card. 14. Install the 28 pin IC socket in the IC-1 area. 15. Carefully install the integrated circuit IC-1. Be sure to mount it correctly (Figure 1). The "dot" on the circuit card should correspond to the "dot" adjacent to pin 1 on the IC. DO NOT TOUCH THE PINS. 16. Double check all components and connections. 17. Measure the voltage across the 200 microF capacitor (C-1). It should be approximately 23 volts. 18. Unplug the line cord before installing hook-up wire jumpers in J-1, J-2. ASSEMBLY OF THE DISPLAY CIRCUIT CARD. Cat. Number 277-108 1. Connect the jumper wires as illustrated on the Display Circuit Card drawing. The drawing is an x-ray view to aid in proper orientation. The jumper wires mount on the side opposite the printed circuit and pass through the holes provided to connect to the printed circuit. 2. Mount the LED digital displays on the same side as the jumpers. Be sure to position them as shown in Figure 2 (note the location of pin 1). NOTE: The basic idea is to connect corresponding segments from each digit display together on a common run (buss). For example, the "A" segments from each digit are connected together via the segment "A"(SA) buss. Likewise for segments B through G. The seven segment busses are then connected with hook-up wire to the proper segment driver outputs from the Digital Clock Circuit Card. 3. Mount the four red light emitting diodes (LED's) CR-6 through CR-9. They form the colons (:) separating the hours digits from the minutes digits and the minutes digits from the seconds digits. The diodes are wired in series, forward conducting, by making use of unused segment busses and suitable jumpers. The anode end of the series string is connected to the plus (:+) output from the Clock Circuit Card. The cathode end is connected to the minus (:-) output. 4. To install CR-10 (see inset 2 on the IC schematic): NOTE: Connect directly to printed circuit side board. a. Connect point A with hookup wire to terminal LED-. b. Connect point B with hookup wire to terminal LED+. 5. Mount LED CR-10 on the same side as the jumpers and below the last digit display (seconds) at points C and D. FINAL ASSEMBLY 1. Connect the Display segment busses with hook-up wire to their corresponding segment driver outputs on the Digital Clock circuit card (Figures 1 and 2). Dress the wires together into a neat and flexible cable. 2. Connect the anode of each digit with hook-up wire to the proper digit driver output from the clock circuit card as follows: (Figures 1 and 2): Seconds digit anode to output D-1 (digit 1) Ten Sec. digit anode to output D-2 Minutes digit anode to output D-3 Ten Min. digit anode to output D-4 Hours digit anode to output D-5 Ten Hrs. digit anode to output D-6 (Digit 6) 3. The decimal point of Digit 6 (Ten Hours digit) acts as an AM/PM indicator. Connect the Digit 6 DP to the Clock Circuit card am/pm output. 4. Connect the anode end of the colons with hook-up wire to the plus (:+) output from the Clock circuit card. Connect the cathode end to the minus (:-) output. 5. Connect the "Hours Set" pushbutton switch S-4 with hook-up wire to the terminals K and L. 6. Connect the "Ten Minutes Set" pushbutton switch S-5 with hook-up wire to terminals M and N. 7. Connect the "Snooze" pushbutton switch S-1 with hook-up wire to terminals Y and Z. 8. Connect the "Alarm Enable" toggle switch S-2 with hook-up wire to terminals W and X. 9. Connect the "Time Selector" toggle switch S-3 with hook-up wire to terminals S and T. NOTE: You may wish to stop the clock at any given time in order to set it exactly. This can be done by substituting a SPDT toggle switch for the SPST toggle switch (S3). Connect the third contact to terminal R (pin 15 to VDD) as shown in Inset #1 on the IC schematic. 10. Connect the speaker to terminals P and U. 11. Double check all wiring against the schematic and assembly drawings. 12. Mount the circuit cards in a enclosure of your own design. (TK/all-11/28/95)