1. Connect these five wires from the JAMA edge connector to connector J5 of the converter board. Refer to the JAMA STANDARD PINOUTS reprinted on the last page of these instructions. Connect:
the RED wire [from JAMA pin 12] to pin 1 of J5,
the GREEN wire [from JAMA pin N] to pin 2 of J5,
the BLUE wire [from JAMA pin 13] to pin 3 of J5,
the VIDEO GROUND wire [from JAMA pin 14] to pin 4 of J5 and
the COMP SYNC wire [from JAMA pin P] to pin 5 of J5.
2. Some video games use stereo sound, some are monaural. Refer to the game manual for speaker connections and then do the following:
A. If the audio output from the game is monaural, connect the speaker wires to pins 13 [-], and 15[+] of J5. [JAMA: pin L = speaker ground, pin 10 = speaker +].
B. If the game is stereo, the edge connector may or may not carry both channels. Refer to the game manual to properly identify the left and right audio outputs NOTE: There is no standard pinout for RIGHT CHANNEL AUDIO on a JAMA harness. Connect the LEFT CHANNEL to pins 1 and 3 of J4 and the RIGHT CHANNEL to pins 4 and 5 of J4.
3. Connect the RGB-NTSC VIDEO CONVERTER BOARD to the power supply by connecting pin 7 of J5 to +12 volts and pin 10 of J5 to ground. At the JAMA edge connector the +12 volts is found on both pin 6 and pin F.
4. Before applying power, be sure to set the dip switches to:
5. Connect the converter board to any standard video monitor, wide screen TV, VCR, or other video device using a standard RCA to RCA patch cord. If the video game has monaural sound, only two cords are used. Connect one of the RCA patch cords between the 'V' jack on the RGB-NTSC VIDEO CONVERTER BOARD and the VIDEO IN jack of the monitor. Use a second patch cord to connect the 'L' jack to the AUDIO IN of the monitor. In addition, if the game is in stereo, connect a third patch cord between the 'R' jack and the AUDIO RIGHT INPUT of the monitor. Note: In the monaural mode, the 'R' jack is not used.
6. Apply power to both the game and the monitor. Be certain that the TV you are using is set for the VIDEO or VCR mode so that it addresses the proper input plug.
7. If necessary, adjust the CLARIFIER capacitor located near the center of the board until the picture is free of distortion. Use a plastic tool, as a metal one will affect the tuning process.
8. Before you screw with the three RED, GREEN, and BLUE level controls, be aware that you will get better results using the COLOR and TINT controls that are part of the TV.
9. SOUND: NEVER OPERATE THE CONVERTER WITH DIP SWITCHES 1 AND 2 OR DIP SWITCHES 3 AND 4 TURNED ON AT THE SAME TIME; DAMAGE TO THE CONVERTER OR THE GAME AMPLIFIER MAY OCCUR. Since the converter board does a current to voltage and impedance match, operation of the converter while both speaker lines are connected may constitute an overload. Be sure to observe this precaution!
Set the sound level on the TV to about a three on a scale of ten and then start a game. If the sound is not clear, TURN OFF DIP SWITCHES 2 and 4, AND THEN turn on DIPSWITCHES 1 and 3. If the sound is still not clear it may be necessary to adjust the game volume DOWN to decrease distortion. Find a good balance between the volume control on the game board and the one on the TV.
NOTES: Although these instructions are written to help you install the RGB-NTSC VIDEO CONVERTER BOARD in a JAMA standard video game, it can be used with any video board on which you can identify the R, G, B, ground, SYNC, and +12 volt wires.
Ground is found on the JAMA standard connector at both ends and both sides; pins 1, 2, 27, 28, A, B, e, and f.
While the preferred operating voltage is +12 volts, the converter will operate normally at any voltage between 8 and 24 volts DC.
The converter can be changed from NTSC to PAL modes by replacing the 3.57 MHz crystal with a 4.48 MHz crystal and changing the jumper as shown in the diagram.
This product sells for $199. and is available directly from TWOBITS.com.
Visit the RGB to NTSC convertor page.
Visit the Twobits.com homepage.