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GBS-8200 Manual (CGA to VGA converter)

This GBS-8200 manual covers the configuration, operation, and troubleshooting for the GBS-8200/GBS-8220. It converts CGA, EGA, and YUV (component) to VGA. This allows you to connect older equipment to VGA TFT monitors or to new HDTVs that have a VGA input.

You can buy the GBS-8200 in our online store.

GBS-8200 Features

  • Supports CGA, EGA, and YUV (component) signal input
  • Supports VGA at
    • 640×480
    • 800×600
    • 1024x768
    • 1360×768
  • CGA and EGA signal auto scan at 15, 24,, and 31 KHz
  • YUV (YPbPr) signal auto scan at 480i/480p, 576i/576p, 720i/720p, and 1080i/1080p
  • On-screen display supports English and Chinese
  • Adjustable position zoom controls
  • True digital 24-bit A/D converter for true 16.7-million color conversion
  • Supports all VGA monitors, including CRT, LCD, PDP, and projectors


In addition to this GBS-8200 manual, the following items are included in the box:

  • The main GBS-8200/GBS-8220 PCB
  • Power Cable (2 pin, +5V)
  • TGB Cable (8 pin, 6 wire)

GBS-8200 Menu Control

MENUOpens the on-screen-display (OSD) and works as the “enter” key.
UPup / increase
DOWN/AUTOdown / reduce

When not in the OSD menu:
Press this key to auto scan for a CGA or EGA signal.
Press and hold for 5 seconds, then release to reset the system.
SWWhen not in the OSD menu:
Switches input signal between YUV / RGBS / RGBHV.
Clamp sp / Clamp stThis is for adjusting the output if your picture has black spots or discolorations.

Power Supplies

  • Power cable (2 Pin Connector)
  • Multi-Voltage Power Supply:
    • Switching Power Supply (Center Positive)
    • Input: 100-240VAC
    • Output: 5V DC 2.0A

GBS-8220 Board Layout and Diagram

No GBS-8200 manual would be complete without a board layout and diagram! The board is laid out as follows:

GBS-8220 Manual: Basic Configuration and Installation

Connect the output monitor (your VGA monitor) to:

  • The VGA OUT connector (sometimes labeled P4), if your monitor uses a 15-pin DSUB connector.
  • To the 12 pin VGA header if your monitor has a ribbon cable.

Connect the CGA, EGA, or YUV output from your JAMMA connection to:

  • The 5 pin RGB input header if your JAMMA connector already has one wired up (most common).
  • Or, use the included 5 pin RGB adapter cable and make the following connections:
    • Red Video to Red Wire/P11 (R)
    • Green Video to Green Wire/P11 (G)
    • Blue Video to Blue Wire/P11 (B)
    • H. Sync to Gray Wire/P11 (S)
    • V. Sync to Yellow Wire/P11 (VS)
    • Ground Ref to Black Wire/P11 (GND)

For more information on the JAMMA Pinout go here.

Connect the GBS-8220 PCB to your +5VDC Power Source:

  • Connect the RED wire of the power cable to the +5VDC source and the BLACK wire to the DC GROUND source. connect the 2-pin.
  • Connector the power cable to P9 on the GBS-8220 converter PCB.

Note: The power requirement for the GBS-8220 is +5VDC +/- .5VDC @ 2A. If the power supply is unable deliver 2amps, the GBS-8200 will behave erratically.

Power up the GBS-8220 Converter

  • Power up the GBS-8220 converter and wait 5 seconds.
  • Press the AUTO button on the GBS-8200/8220 PCB. This should self-adjust and lock-in the picture on your VGA output monitor.

If you don not see a picture:

  • Remove the P11 wire harness from the converter P11 connector.
  • Move the GRAY wire over one position on the connector (so it is next to the YELLOW wire).
  • Connect back into the converter and power up then try the AUTO button again.

GBS-8200/GBS-8220 Troubleshooting FAQ

In addition to providing a GBS-8200 manual, the following are some common troubleshooting questions and answers:

Q: No signal displayed on monitor
Check that both the input and output cables are connected and that the power to the GBS-8200/8220 is on. Try pressing the SW button to change input sources.

Q: “Input not supported” is displayed on the screen.
Your monitor may not support all resolutions. Lower the output resolution. You can also reset the GBS-8200 to its default 800×600 resolution by pressing DOWN/AUTO for 5 seconds and releasing.

Q: Image does not fill the screen.
Use the position and zoom controls to adjust.

Q: Image shakes or freezes
Press DOWN/AUTO to initiate an auto scan. This should restore the image.

Q: Black area on the screen, screen is too dark, or colors are not correct.
Adjust “Clamp sp” and “Clamp st” while keeping “Clamp st” less than “Clamp sp”. Generally “Clamp st” set to 3 and “Clamp sp” sett to 4 will be optimal.

Q: Image color not right
Use RGB ADJUST potentiometers to correct colors.

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3 Responses

  1. Hi Mike, Can you confirm: Will this convert the output from an old IBM PC CGA (Color graphics adapter) (9-pin TTL) to VGA? I need to test several older PC… THANKS!
    Regards, Terry King terry@terryking.us
    …In The Woods In Vermont
    The one who dies with the most Parts LOSES! WHAT DO YOU NEED??

  2. I too wish to know if my old 1988 MCGA monitor can be replaced by something like this for VGA.
    The pin out for the MCGA monitor is as follows:
    Pin1: Composite H & V sync
    Pin2: Intensity
    Pin3: GND
    Pin4: Black
    Pin5: Green
    Pin6: Blue
    Pin7: GND
    Pin8: Red
    Thank you for any help.

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