| WARNING!!
It can be very dangerous to fiddle around inside any monitor.
The monitor and the flyback transformer can hold up to 30,000
volts. Do not attempt any modification if you don't know what
you are doing. |
| After looking at many example projects and
playing MAME on the PC, I decided that I would try to use the
arcade monitor I already had in the cabinet. The PC monitors
were expensive and I already had sunk a lot of money into this
project, plus it just didn't look the same on a PC monitor.
So I looked into interfacing the PC to the original 18 year
old Defender monitor I had. It is a 19" Electrohome GO7-CBO.
To improve that picture, I first installed a 'Cap kit'. This
is basically just replacing all the capacitors on the monitor
main board. I first discharged that monitor then removed that
main board and replaced the capacitors. DISCHARGING THE MONITOR
IS DANGEROUS! BE CAREFUL! Learn more about installing a cap
kit from Al's guide to installing a cap kit. Cap
kit installation 101. This actually helped the picture quite
a bit. The screen had very little burn in so I was lucky. |
| VGA to arcade monitor interface |
|
Arcade monitors cannot handle the frequencies of standard
VGA output. Because of this we need to provide a signal that
the monitor can handle. I use ArcadeOS as my MAME frontend.
It is perfect for an arcade cabinet because it supports arcade
monitor frequencies and also passes the settings to MAME.
ArcadeOS was developed by Brian
Lewis for his PC2JAMMA project. Check out his page and
ArcadeOS HERE.
A list of video card that are known to work with ArcadeOS
and an arcade monitor is HERE.
I am using an ATI Expert98 video card.
Now that we can provide the proper signal we need to make
the connection from the PC to the monitor. To do this is actually
very simple. The GO7-CBO has pinouts on the monitor for RED,
GREEN, BLUE, GROUND, H-SYNC, and V-SYNC. These are the only
signals we care about. Here are the pinouts of a standard
VGA cable:
|
| Pin |
Signal |
| 1 |
Red |
| 2 |
Green |
| 3 |
Blue |
| 4 |
- |
| 5 |
Ground |
| 6 |
Red
Return |
| 7 |
Green
Return |
| 8 |
Blue
Return |
| 9 |
- |
| 10 |
Ground |
| 11 |
Ground |
| 12 |
- |
| 13 |
Horizontal Sync |
| 14 |
Vertical Sync |
| 15 |
- |
|
We only care about pins 1, 2, 3, 5, 13, and
14. These pins need to be connected to the correct pins on the
monitor. To do this, I got a generic video cable from Radio
Shack, and then cut the end off of one side. I then cut the
wires from the original video connection to the arcade monitor
leaving about 8 inches of wire remaining. Looking at the connector
of the VGA cable I identified the wires by the little tiny numbers
on it. I then soldered the wires to the wires of the arcade
cable and wrapped it in electrical tape. If the monitor only
has one sync wire, it may work by attaching both the V-sync
and H-SYNC together. This is what my cable looks like. |
| I have a ZIP file available of
all the monitor rotation pics from this site as well as many
others not contained here. Download
saltypics_zip (5376) 2.1
meg |
| Monitor page II, Monitor connection
& adjustment |
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|
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