RGB voltage levels

aha2940

AH, A, COLUMBIAN!,
Joined
Dec 15, 2013
Posts
2,527
Hey guys

So, I got a little 13" PVM recently and I connected my supergun to it. It works fine, it looks beautiful. However, for whatever reason, I read that typical RGB voltage output from a JAMMA board is about 3-5V on the RGB lines. But reading my PVM instruction manual, it says that the PVM expects 0.7V p-p (peak-to-peak?) on the RGB inputs. These inputs are 75-ohm terminated (whatever that means). So am I feeding too much voltage to the RGB inputs of the PVM? can/will it get damaged? should I put resistors between the JAMMA RGB outputs and the PVM inputs?

Thanks for the guidance, searching for this on google was not very conclusive.
 

skate323k137

Professional College Dropout
10 Year Member
Joined
Jan 7, 2013
Posts
3,771
Most superguns have the resistors built in. I use 220 ohm for JAMMA boards on my PVMs. One resistor each on R G B and sync.
 

mikejmoffitt

Mickey's Coach
Joined
Feb 6, 2014
Posts
578
Hey guys

So, I got a little 13" PVM recently and I connected my supergun to it. It works fine, it looks beautiful. However, for whatever reason, I read that typical RGB voltage output from a JAMMA board is about 3-5V on the RGB lines. But reading my PVM instruction manual, it says that the PVM expects 0.7V p-p (peak-to-peak?) on the RGB inputs. These inputs are 75-ohm terminated (whatever that means). So am I feeding too much voltage to the RGB inputs of the PVM? can/will it get damaged? should I put resistors between the JAMMA RGB outputs and the PVM inputs?

Thanks for the guidance, searching for this on google was not very conclusive.

It will just be too bright in the worst case.

The PVM terminates inputs to 75 ohms (sinking to ground), and many "standard" RGB outputs expect 75 ohm series termination to match it (on most consoles).

RGB outputs made for arcades are seldom terminated this way, and often use a higher value (like 220 ~ 330 ohms). With the wrong termination, a different voltage divider is created.

If it's too bright, you can throw resistors in series.
 

aha2940

AH, A, COLUMBIAN!,
Joined
Dec 15, 2013
Posts
2,527
It will just be too bright in the worst case.

The PVM terminates inputs to 75 ohms (sinking to ground), and many "standard" RGB outputs expect 75 ohm series termination to match it (on most consoles).

RGB outputs made for arcades are seldom terminated this way, and often use a higher value (like 220 ~ 330 ohms). With the wrong termination, a different voltage divider is created.

If it's too bright, you can throw resistors in series.

Thanks for the help, guys. Now I am sure the monitor will not get damaged. The image looks fine to me, so I do not think I need the extra resistors, just wanted to be sure.
 
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