Intv Composite Video Mod


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Click for more formal write-up from Intellivison.us

intv video mod
                     +
        Input  10--|(--+                 ^ +5V
                  CC1  |                 |
                       |                 |
             RB1       |        RA1      |
     0------/\/\/------3------/\/\/------1
     |                 |                 |
     |                 |b                |
     |             ____|____             |
     |               /   \               |
     |            e V     \ c            |
     0---/\/\/-----4       +--2--/\/\/---1
     |    RE1                 |    RC1   |
     |                      + |          |
     |                 +--|(--+          |
     |                 |  CC2            |
     |       RB2       |        RA2      |
     0------/\/\/------6------/\/\/------1
     |                 |                 |
     |                 |b                |
     |             ____|____             |
     |               /   \               |
     |            e V     \ c            |
     0---/\/\/-----7       +---5-/\/\/---1
     |    RE2                  |   RC2
     |                         |
   __|__                       |   +
     -                         +----)|----8---
   GND                             CC3    
               

   Audio             +                      Audio
    in  --------------|(------------------() out
                     100uF (not critical)
 
   * stage 1
   CC1 10 3 100uF
   RA1 1 3 50K  (I used a 51K)
   RB1 3 0 30K  (I used a 33K)
   RC1 1 2 660
   RE1 4 0 330
   Q1 2 3 4 Q2N3904

   * stage 2
   CC2 2 6 100uF
   RA2 1 6 15K
   RB2 6 0 20K  (I used a 22K)
   RC2 1 5 75
   RE2 7 0 22
   Q2 5 6 7 Q2N3904

  Video = modulator pin 1 (counting from edge of board)
  Audio = modulator pin 3

  Intv 1  5v   Bottom of C20 (farthest from edge of board)
          Gnd  Go to bottom of R22 (farthest from edge)
               Right over to C17
               Right one more to empty terminal with thick trace 

  Intv 2  5v   Go between lettering for U12 and U13 then a 
               little to the right (light green)
          Gnd  Right side of C20



COMMENTS
I replaced my old circuit with this new one designed by Joe Zibiciak (with Tim Lindner coordinating). It uses a pair of common-emitter amplifiers to give you voltage gain in addition to current gain. I built this and was very happy, just had a very slight ghosting effect on dark screen characters which was probably my workmanship. Thanks guys.

You can solder the AV cables in directly or mount RCA jacks onto the console case. Either way, remember to ground the shield (outer conductor) Once you do a AV mod, the RF output really become ugly, because the circuit acts like an rf antenna, so don't be surprised.

Intellivision-1s require a lot of work and a hot soldering iron to get the metal shield enclosure off. If the RF video looks OK, you might just want to leave it alone. They also have an internal transformer with 120V connections so don't shock yourself or start a fire. My intv1 eventually went bad, I stick with intv2s now.

That being said, intv2s have very little space to put things. I placed my video circuit in the top right corner of the case, but this meant a long video wire to the modulator. Some games have distortion on the top of the screen and this may be why. By the way, those extra circuits in the bottom part of the picture are to adapt genesis controllers.

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