PORTABLE BLUE BOX PLANS BY FORD PREFECT 
 
(C)OPYRIGHT 5/21/84 TAKEN FROM 2600 MAG. 
 
DIAGRAM #1: 
 
             (A) 
              | 
              | 
              | 
 ------------------------------------- 
D| 1| 2| 3I 4| 5| 6| 7| 8| 9| 0| K| S| 
 /  /  /  /  /  /  /  /  /  /  /  /  / 
 |  |  |  |  |  |  |  |  |  |  |  |  | 
 | -. -. -. -. -. -. -. -. -. -. -. -. 
 | |V |V |V |V |V |V |V |V |V |V |V |V 
 | || || || || || || || || || || || || 
 | || || || || || || || || || || || || 
 | |---.-----.--------.----------------- 
 | |  |  || |  || || |  || || || || || 
 | |  |  |------.--------.-------------- 
 | |  |  |  |  |  || |  |  || || || || 
 | |  |  |  |  |  |---------.----------- 
 | |  |  |  |  |  |  |  |  |  || || || 
 | |  |  |  |  |  |  |  |  |  |--------- 
 | |  |  |  |  |  |  |  |  |  |  |---.-- 
 | V  V  V  V  V  V  V  V  V  V  V  V 
 | |------------------------------------ 
 |    |  |  |  |  |  |  |  |  |  |  | 
 |    ---.-----------------------.------ 
 |          |  |  |  |  |  |  |     | 
 |          ---.--.--------------------- 
 |                   |  |  |  |     |    
 |                   ---.--.--.-----.--- 
 |                                       
 |-------------------------------------- 
                                        
DIAGRAM #2:                             
---700---          (B)                  
        |        ------- (C) 
---900--.    |---|2  10|--|(-- 
        |    |   |     |     | 
--1100--.----|-.-|4  11|-----.--| 
        |    | --|5    |     |  | 
--1300--.    |   |   12|-/|/--  V 
--1700--|  --|   |6    | (D)      
           | |   | 78  |    <--25K POT. 
---900--| (A)|   ------- 
        |    |     |-| 
--------.    |---/|/|/--- 
  1100  |         (E)   | 
--------.----           | 
  1300  |  (*)          | 
--------.            ------- 
        |            |  3  |  <--OP-AMP 
--2600---       (A)--|7    | 
                     |     | 
               |-----|4    | 
               V    -|2    | 
(*)25K POT. SHOULD  ||    6| 
BE THE SAME         |-----|- 
AS THE ONE TO       |-----. 
THE ABOVE RIGHT.          | 
BOTH GO TO PIN            | 
3 OF THE OP-AMP.    (|    | 
                (G) ||-)|-| 
                    || (H) 
                    (|-| 
                       | 
                       V 
  
DIAGRAM #3: 
                     (J) 
   (I)     ---------|---| 
|-||||||--.|        |1  | 
V          |        |  2|--.-- +10V 
           --|(/|/-.|3  |  / 
            (K)(M) |-----  ) 
                   --------| (L) 
 
 
DIAGRAM #2 SHOULD CONNECT TO THE RIGHT OF DIAGRAM #1, MY 40 CHARACTER DISPLAY 
REQUIRES I CUT IT OFF HERE. IF YOU CUT A PRINTOUT OF #2 OUT AND PLACE IT 
TO THE RIGHT OF #1 THEY SHOULD MATCH UP PERFECTLY. DIAGRAM #3 IS THE SCHEMATIC 
FOR THE POWER SUPPLY. 1 AND 2 OF COURSE ARE THE BOX ITSELF. 
  
   NOTE:   |             | 
          -.-           --- 
       THESE WIRES   THESE WIRES 
        CONNECT.        DON'T. 
  
LEGEND: 
 
(A) +10 VOLT (THIS IS WHERE THE POWER 
             SUPPLY CONNECTS TO THE  
             BOX.) 
(B) 8038 IC 
(C) .010F MYLAR CAP. 
(D) 82K RES. 
(E) 100K RES. 
(F) 741 OP-AMP 
(G) 8 OHM SPEAKER 
(H) 100F CAPACITOR 
(/) SPST MOM CONT NO PUSHBUTTON SWITCH 
(V) 1N914 DIODE 
(I) (2) 9V BATTERIES 
(J) LM317T 
(K) .010F CAPACITOR 
(L) 470 OHM RESISTOR 
(M) 3.3K RESISTOR 
(V) TO GROUND 
  
PARTS DESCRIPTION: 
 
(A) CONNECT THE OUTPUT FROM THE POWER 
    SUPPLY HERE. 
(B) 8038 WAVEFORM GENERATOR 
(C) .010F MYLAR CAPACITOR 
(D) 82K RESISTOR (YOU WILL HAVE TO USE 
    2 OR MORE IN SERIES.)(RESISTENCE IS 
    ADDITIVE IN SERIES.) 
(E) 100K RESISTOR (5% IS BEST.) 
(F) 741 OP-AMPLIFIER 
(G) 8 OHM SPEAKER 
(H) 100F CAPACITOR 
(I) 2 9V BATTERIES IN SERIES 
(J) LM317T VOLTAGE REGULATOR 
(K) .010F CAPACITOR 
(L) 470 OHM RESISTOR 
(M) 3.3K RESISTOR 
(/) SINGLE-POLE SINGLE-THROW MOMENTARY- 
    CONTACT NORMALLY-OPEN PUSHBUTTON 
    SWITCH. 
(V) 1N914 SIGNAL DIODES 
 
RADIO SHACK PARTS NUMBERS: 
 
(B) 276-2334 (C) 272-1065 (E) 271-1347 
(F) 276-007  (H) 272-1065 (J) 276-1778 
(K) 272-131  (L) 271-019  (M) 271-019 
(/) 275-1547 (V) 276-1122 
 
 
THE SPOT ON THE DIAGRAM THAT HAS 700, 900, ETC. SHOULD BE FILLED IN WITH A 25K 
MULTI-TURN POTENTIOMETER (VARIABLE RESISTOR). THE 15-TURN POT FROM RADIO 
SHACK (#271-340) WILL WORK IF A 1/4 WATT, 5%, 5K RESISTOR IS PUT IN SERIES. 
 
THE EASIEST WAY TO TUNE THE BOX IS TO PLAY BOTH IT AND A SAMPLE OF THE TRUE 
SOUND TOGETHER, THEN ADJUST THE BOX UNTIL ONLY 1 NOTE CAN BE HEARD. AS 
INACCURATE AS THIS SOUNDS, THIS IS MORE THAN ACCURATE ENOUGH FOR THE FONE 
COMPANY. THE APPLE WITH AN APPLE CAT MODEM, THE ATARI, THE COMMODORE, AND THE 
TEXAS INSTRUMENTS CAN ALL GENERATE THE NEEDED TONES. 
 
THESE PLANS ARE BASED ON A SET OF PLANS I (FORD PREFECT) RECEIVED TWO YEARS 
AGO. THEY WERE ALMOST ILLEGIBLE AND THE POWER SUPPLY INCLUDED OUTDATED PARTS. 
THE TOTAL COST IS SLIGHTLY ABOVE $50 BUT WHEN PROPERLY ASSEMBLED IT WILL WORK 
PERFECTLY. (THESE PLANS HAVE BEEN FIELD TESTED!) 
 
(THIS SCHEMATIC HAS BEEN COPIED BY SALLY RIDE SPACE CADET FROM THE OCTOBER '85 
ISSUE OF 2600 MAGAZINE. THE ONLY TRUE AND RELIABLE PUBLICATION FOR PHREAKS AND 
HACKERS. SUBSCRIPTIONS ARE $12 A YEAR, BACK ISSUES MAY BE PURCHASED FOR $2 
EACH. WRITE TO: 
 
2600 
P.O. BOX 752 
MIDDLE ISLAND, NY 
11953-0752 
 
MAKE CHECKS PAYABLE TO 2600 ENTERPRIES, INC. OR, CALL 2600 AT 516-751-2600,OR 
CALL THEIR BBS THE PRIVATE SECTOR ON 201-366-4431. 
 
SYSOPS MAY USE THIS FILE IF RETAINED IN IT'S ENTIRETY. FOR ANY SUGGESTIONS, 
ADVICE OR COUNCIL YOU MAY CONTACT SALLY ON ANY ONE OF THESE EXCELLENT BBS, THE 
TWILIGHT ZONE, STRONGHOLD EAST ELITE, SPEED DEMON ELITE. AND, MANY OTHER BBS AS
WELL, CHECK THE USER LIST I MAY BE THERE. 
