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- ---===<*> Building Of A Blue Box ! <*>===---
-
- WE ALL KNOW THAT THE TOUCH TONES FREQUENCIES ARE COMPOSED
- OF TWO TONES (TWO DIFFERENT FREQS.) SO THAT IS THE REASON
- WHY WE HAVE 2 VCO'S ( VOLTAGE CONTROLLED OSCILLATORS). WE
- WILL CALL THESE VCO#1 AND VCO#2. IF YOU HAVE NOTICED
- VCO#1 AND VCO#2 ARE EXACTLY THE SAME TYPE OF CIRCUITS.
- THAT IS WHY ONLY ONE WAS DRAWN. BUT REMEMBER THAT WHATEVER
- GOES FOR VCO#1 ALSO GOES FOR VCO#2. BOTH VCO'S ARE COMPOSED
- OF A HANDFULL OF PARTS. ONE CHIP TWO CAPACITORS 2 RESISTORS
- AND FIVE POTENTIOMETERS. ALL OF THIS WILL GIVE YOU (WHEN PROPERLY
- CALIBRATED) ONE OF THE FREQS. NECESSARY (THE OTHER ONE WILL
- COME FROM VCO#2) FOR THE OPERATION OF THE BB. BOTH OF THESE
- FREQS. WILL BE MIXED IN THE SPEAKER THUS FORMING THE REQUIRED
- TONE.
-
- THIS IS ONE OF THE MOST SOPHISTICATED DESIGNS I HAVE EVER MADE.
- WHY?. BECAUSE OTHER DESIGNS WILL DRAIN THE BATTERY AFTER 10 -
- CALLS! THIS DESIGN WILL MAKE THEM LAST 10 MONTHS!!!!!!. BUT
- NEVERTHELESS DON'T FORGET TO PUT IN A SWITCH FOR ON AND OFF.
- OK LET'S BUILD THE TWO VCO'S AND CALIBRATE THE UNIT BEFORE
- WE GET TO THE KEYBOARD CONTRUCTION.
-
- VCO CONTRUCTION
- === ===========
- TOOLS REQUIRED
-
- 1 OSCILLOSCOPE (RECOMMENDED BUT NOT REQUIRED)
- 1 FREQ. COUNTER (REQUIRED)
- 1 VOLT METER " " "
- ELECTRONICS TOOLS (PLIERS, DRILL, SCREWDRIVERS, ETC)
-
-
- PARTS
-
- R1 1.5K RESISTOR 5%
- R2 1K RESISTOR 5%
- C1 .1UF ELECTROLYTIC CAPACITOR 16VDC
- C2 .01UF ELECTROLYTIC CAPACITOR (MYLAR) 16VDC
- IC1 2207 VCO CHIP BY EXAR ELECTRINICS
- REMEMBER THE ABOVE IT IS ONLY FOR VCO#1 BUT THE SAME GOES FOR
- VCO#2.
-
- R3-R4 150 OHM RESISTORS 5%
- C3-C4 .1 UF ELECTROLITIC CAPACITOR 10VDC
- P1-P10 200K TRIMMER POT - 20 TURNS
- DIODES USED IN THE KEYBOARD ARE 1N914 TYPE (40 OF THEM)
- AND 13 SWITCHES FOR THE KEYBOARD SPST. MOMENTARY.
-
- SPKR= YOU CAN USE A TELEPHONE SPEAKER FOR THIS(IT WORKS BEST)
- BUT REMEMBER TO TAKE OUT THE DIODE THAT IS CONNECTED
- ACCROSS IT.
- ****************************************************************
- IMPORTANT NOTES
-
- 1 DO NOT USE ANYTHING ELSE THAN A MYLAR CAPACITOR FOR C2
- 2 PINS 10,9,8 SHOULD BE TIED TOGETHER AND BE LEFT FLOATING.
- 3 ALL RESISTOR SHOULD BE 5%! NOTHING ELSE
- 4 A TELEPHONE SPEAKER GIVES THE BEST RESULTS
- *****************************************************************
-
-
- TROUBLE SHOOTING
-
- BY NOW YOU SHOULD HAVE CONSTRUCTED THE TWO VCO'S
- ON A BREAD BOARD OR ANYTHING THAT PLEASES YOU.
-
- CHECK FOR COLD SOLDER JOINTS, BROKEN WIRES, POLARITY
- OF THE BATTERY, ETC.........
-
- BEFORE WE APPLY POWER TO THE VCO'S WE HAVE TO ADJUST THE POTS
- FOR THEIR HALF WAY TRAVEL POINT. THIS IS DONE BY TURNING THEM
- 21 TURNS TO THE RIGHT AND THEN 10 TURNS TO THE LEFT. DO THE
- SAME FOR ALL TEN OF THEM.
-
- NOW APPLY POWER TO THE UNIT CHECK TO SEE THAT YOU HAVE POWER
- IN THE CHIPS BY PUTTING THE POSITIVE LEAD OF YOUR VOLT METER
- ON PIN 7 AND THE NEGATIVE LEAD ON PIN 12. IF YOU DON'T HAVE
- ANYTHING THERE TURN OFF THE UNIT ANT RECHECK THE WIRING.
-
- WHEN YOU GET THE RIGHT VOLTAGES ON THE CHIPS, CONNECT A
- DIODE TO A PIECE OF WIRE (LOOK AT FIG. 2 FOR THE ORIENTATION
- OF THE DIODE) FROM GROUND TO ANY POT AT POINT T (LOOK CAREFULLY
- AT THE SCHEMATIC FOR POINT T IT IS LABELED T1-T10 FOR ALL POTS)
- YOU SHOLD BE ABLE TO HEAR A TONE, IF NOT DISSCONNECT THE LEAD
- AND PLACE THE SPEAKER CLOSE TO YOUR EAR AND IF YOU HEAR A CHIRP
- LIKE SOUND, THIS MEANS THAT THE TWO VCO'S ARE WORKING IF YOU DON'T,
- IT MEANS THAT EITHER ONE OR BOTH OF THE VCO'S IS DEAD.
- SO IN THIS CASE IT IS ALLWAYS GOOD TO HAVE AN OSCILLOSCOPE ON HAND.
-
- DISCONNECT THE SPEAKER FROM THE CIRCUIT AND HOOKUP THE OCILLISCOPE
- TO ONE OF THE LEADS OF THE SPEAKER AND THE GROUND FROM THE SCOPE
- TO THE GROUND OF THE BATTERY. CONNECT AGAIN THE GROUND LEAD
- WITH THE DIODE CONNECTED TO IT FROM GROUND TO ANY POT ON THE
- VCO THAT YOU ARE CHECKING AND YOU SHOULD SEE A TRIANGLE WAVE
- IF NOT TURN THE POT IN WICH YOU ARE APPLYING THE GROUND TO
- QUNTIL YOU SEE IT. WHEN YOU DO SEE IT DO THE THE SAME FOR THE
- OTHER VCO TO MAKE SURE IT IS WORKING. (AMPLITUDE IS ABOUT 2VAC)
- WHEN YOU GET THE TWO VCO'S WORKING YOU ARE SET FOR THE ADJUSTMENT
- OF THE INDIVIDUALS POTS...
-
- ADJUSTMENT
-
-
- DISCONNECT THE SPEAKER FROM THE CIRCUIT AND CONNECT A FREQ.
- COUNTER (THE POSITIVE LEAD OF THE COUNTER TO ONE OF THE SPEAKERS
- LEADS THAT BELONGS TO VCO#1 OR CONNECT IT TO PIN 14).
-
- CONNECT THE NEGATIVE LEAD TO THE BATTERY NEGATIVE AND
- CONNECT THE JUMPER LEAD WITH THE DIODE FROM GROUND TO POT NUMBER 1
- T1 .( THE FIRST POT NUMBER 1 POINT T1)
- IF YOU GOT IT WORKING YOU SHOULD HEAR A TONE AND GET A READING ON THE
- COUNTER. ADJUST THE POT FOR A FREQ. OF 1700HZ AND CONTINUE DOING THE
- SAME FOR POTS 2-5 EXCEPT THAT THEY GET DIFFERENTS FREQS.
-
-
- P1= 1700HZ
- P2= 1300HZ
- P3= 1100HZ
- P4= 900HZ
- P5= 1500HZ
-
- NOW DISCONNECT THE FREQ. COUNTER FROM THE SPEAKER LEAD OF VCO#1 OR
- FROM PIN 14 (WHICH EVER YOU HAD IT ATTACHED TO AT THE BEGINNING) AND
- CONNECT IT TO THE SPEAKER LEAD OF VCO#2 OR TO PIN 14 OF VCO#2 AND
- PERFORM THE SAME ADJUSTMENTS TO P6-10.
-
- P6= 1100HZ
- P7= 700HZ
- P8= 900HZ
- P9= 2600HZ MAGIC NUMBER!!!!!
- P10= 1500HZ
-
- WHEN YOU FINISH DOING ALL OF THE POT GO BACK AND RECHECK THEM
- AGAIN.
-
-
- KEYBOARD
- IF YOU LOOK AT FIG-2 YOU WILL SEE THAT THE KEYS ARE SIMPLE SWITCHES
- CONNECTED TO GROUND AND TWO DIODES ON THE OTHER END. THESE DIODES
- ARE USED TO SIMPLIFY THE CONSTRUCTION OF THE KEYBOARD BECAUSE OTHERWISE
- THE DISTRIBUTION OF THE GROUND SIGNAL FOR BOTH VCO'S WOULD HAVE BEEN
- DONE MECHANICALLY. ONE DIODE WILL GO TO VCO#1 AND THE OTHER WILL GO TO
- VCO#2. FIG-3 SHOWS THE ARRANGEMENT OF THE KEYS ON THE KEYBOARD.
-
-
- DBELOW IS A TABLE THAT WILL HELP YOU CONNECT
- THE KEYS TO REQUIRED VCO'S POTS.
-
- TO TO FREQ OUT FREQ OUT
- KEY POT ON VCO1 POT ON VCO2 PIN 14 VCO1 PIN 14 VCO
- C 1 6 1700 1100
- 0 2 10 1300 1500
- E 1 10 1700 1500
- 1 4 7 900 700
- 2 3 7 1100 700
- 3 3 8 1100 900
- 4 2 7 1300 700
- 5 2 8 1300 900
- 6 2 6 1300 1100
- 7 5 7 1500 700
- 8 5 8 1500 900
- 9 5 6 1500 1100
- X - 9 ---- 2600
-
- ***********************************************************************
- * REMEMBER THAT FIG-2 IT IS THE SAME FOR EACH KEY EXCEPT THE "X" WHICH*
- * ONLY TAKES ONE DIODE. *
- ***********************************************************************
-
-
- AS A FINAL WORD YOU CAN BUILD THIS IN ANY TYPE OF ENCLOSURE
- AND SHOULD NEVER BE USED TO MAKE FREE CALLS USING THE TELEPHONE
- LINES. I HOPE THIS BULLETIN WILL CLEAR ANY QUESTION YOU MAY
- HAD ON THE BLUE BOXES.
-
- KEY
- ===
-
-
- FIRST A FEW KEYS TO THE DIAGRAM:
-
- CX IS CAPACITOR #X DENOTED BY: ---] ]---
-
-
- PX IS POT OR VARIABLE RESISTOR #X DENOTED BY :/
- \
- /<--
- \
- RX IS RESISTOR #X DENOTED BY /\/\/\/\
-
-
- SCHEMATICS
- ==========
-
- THE XR-2207 CHIP IS A VOLTAGE-CONTROLLED OSCILLATOR AND A 14
- PIN DEVICE TH
- US YOU MUST BE VERY CAREFUL WHEN SOLDERING THE PARTS
- TO THIS DEVICE. IT IS A LITTLE DIFICULT TO ACTUALLY DRAW A
- SCHEMATIC ON A 80 CHARACTER SCREN USING LIMITED GRAPHICS BUT WILL
- GIVE IT A TRY.
- TO GND_____________
- ]
- ___
- C2 C3 ___
- ']]' ]
- ] ] _____]__9V+
- ] ] ] ]
- ' ' ' ' ' ' ' ]
- ------------------------------- ]
- ]7 6 5 4 3 2 1 ] ]
- ] < ]
- ]8 9 10 11 12 13 14] ]
- ------------------------------- ]
- ' ' ' ' ' ' ' ]
- ] ] ]
- --] ]--------] ] ]
- ]C1 R2 ] R1 ]
- GND ______]___/\/\/\/\______]_____/\/\/\/\______]
-
-
- THIS IS A DIAGRAM OF HOW TO LOCATE THE DIFFERENT PINS ON THE
- CHIP PLEASE NOTICE THAT PIN ONE IS THE CLOSEST TO THE NOTCH ON TOP
- OF THE CHIP. THE FIRST THING WE'LL DO IS TO CONNECT POWER TO THE
- CHIP (REMEMBER THAT YOU NEED TO BUILD TWO OF THESE TO GET A
- COMPLETE SYSTEM) THIS IS ACCOMPLISHED BY CONNECTING THE POSITIVE
- WIRE OF THE BATTERY LEAD TO PIN 1 ONE LEG OF R1 AND R2 IS SOLDER
- TO PIN 11 THE OTHER LEG OF R1 GOES TO PIN 1 OR TO THE POSITIVE OF
- THE BATTERY. THE OTHER LEG OF R2 GOES TO GROUND, C1 GOES BETWEEN
- PIN 10 AND GROUND.
- THE TIMING CAPACITOR OR C2 GOES BETWEEN PINS 2 AND 3 OF THE CHIP
- PINS 8 AND 9 SHOULD BE GROUNDED TO GROUND. PIN 14 IS THE OUT PUT
- AND THIS IS WHERE ONE LEG OF C4 (C3 GOES ON THE OTHER VCO) IN
- SERIES WITH R3(THE SAME GOES FOR THE OTHER VCO) AND TO ONE LEAD
- OF THE SPEAKER.
-
-
- THE TRIMMER POTS P1 TO P10 SHOULD BE GROUPED IN GROUPS OF 5
- POTS EACH. THE WAY YOU GROUP IT IS BY SOLDERING ONE END OF THE
- POT TO EACH OTHER LEAVING THE WIPER AND THE OTHER END FREE.
-
- ] THIS END GOES TO PIN 6 OF THE CHIP
- ]
- _____________]_____________
- / / / / /
- \ \ \ \ \
- /<- /<- /<- /<- /<-
- \ ] \ ] \ ] \ ] \ ]
- / ] / ] / ] / ] / ]
- ] ] ] ] ]
- ] ] ] ] ]
- P1 P2 P3 P4 P5
-
-
- AND FINALLY THIS IS THE WAY EACH KEY SHOULD BE WIRED.
-
- DIODE
- TO PX ------>]-----] THIS IS THE CONTACT OF THE KEY
- ]--------- \------
- TO PX ------>]-----] ]
- DIODE ]
- -----
- --- GROUND
- -
-