Looking for RGB to JAMMA Help

Discussion about displays and related hardware including MiSTer filters and video settings.
Sumolx
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Joined: Sun Jun 07, 2020 1:50 am
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Looking for RGB to JAMMA Help

Unread post by Sumolx »

I have purchased Antonio's Jamma adapter in the hopes that I could connect the Mister to my Arcade Cabinet and while it works there are issues with the RGB levels. Specifically Red and Green are very low when performing a color bar comparison where blue looks correct. I have tested the jamma interface with both the Analog IO 6.1 output and HDMI to VGA adapter using direct video option. If i use the vga scaler I can verify both IO and HDMI to VGA adapters produce the proper RGB levels on my TV. I can also confirm that all my JAMMA boards are of equal levels on my arcade cabinet. I have performed the following resistance measurements of the video amplifier and associated resistors for each color channel.

I'm hoping someone could also perform the same measurements with either their own Antonio's JAMMA adapter or against the THS7374 video ampifier. Here are the following measurements I have performed:

Resistor Array 330 Ohms:
RIN - 332.93
GIN - 333.87
BIN - 332.82

Resistor Array 220 Ohms:
ROUT - 216.99
GOUT - 218.05
BOUT - 218.19

THS7374 video amp pins:
Pin 1 - 2 = 660 (RG IN)
Pin 1 - 3 = 660 (RB IN)
Pin 2 - 3 = 660 (BG IN)

Pin 14 - 13 = 19K (RG OUT)
Pin 14 - 12 = 19K (RB OUT)
Pin 13 - 12 = 38K (BG OUT)

Pin 1 - 14 = 658 (RIN/ROUT) <- Not sure why this one reads so low
Pin 2 - 13 = 19.2k (GIN/GOUT)
Pin 3 - 12 = 19.2k (BIN/BOUT)

Resistance between ground and the following jamma video pins:
R: 542 <- Not sure why this one reads so low
G: 19.1K
B: 19.1K
S: 386K

Attachments
Antonio's Jamma Adapter
Antonio's Jamma Adapter
antonio-jamma.jpg (366.32 KiB) Viewed 7310 times
Analog IO 6.1
Analog IO 6.1
analog-io-rgb.jpeg (756.81 KiB) Viewed 7311 times
Sumolx
Posts: 68
Joined: Sun Jun 07, 2020 1:50 am
Been thanked: 20 times

Re: Looking for RGB to JAMMA Help

Unread post by Sumolx »

Antonio sent a replacement board and the issue is now resolved. It was a bad video amplifier. Excellent support by him and I'm enjoying the Jamma adapter immensely.

This thread can be closed as resolved.

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