k7502 Chassis Ground

the5er

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Hey guys,

Trying to get a look at running a championship sprint on a 27" k7502 monitor i found... thinking I may do a custom project cab to house the bigger monitor if it looks cool.

Anyway, game runs on the traditional combo of the Atari Power Brick and the 5v switching PS.

Looking the k7502, the AC input has a 3 input terminal (to include ground). whereas the current k4915 runs only from the line/hot which is just a two wire terminal.

Should I be concerned with adding the ground wire to the 3 terminal input connector? If so, where should that ground wire come from? The FG on the switching PS?

Or can I get by with just the line/hot?

Thanks guys, really appreciate some guidance.

5er
 

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The ground is advised, but not necessary. Yes, you can run a wire from the Earth Ground at the power supply (assuming you have one feeding it from the Earth Ground of the cabinet). If you don't, then you CAN get by with just the hot and neutral inputs.

Hey guys,

Trying to get a look at running a championship sprint on a 27" k7502 monitor i found... thinking I may do a custom project cab to house the bigger monitor if it looks cool.

Anyway, game runs on the traditional combo of the Atari Power Brick and the 5v switching PS.

Looking the k7502, the AC input has a 3 input terminal (to include ground). whereas the current k4915 runs only from the line/hot which is just a two wire terminal.

Should I be concerned with adding the ground wire to the 3 terminal input connector? If so, where should that ground wire come from? The FG on the switching PS?

Or can I get by with just the line/hot?

Thanks guys, really appreciate some guidance.

5er
 
monitors with the 3 pin plugs are actually intended to plug straight into a wall outlet. no isolation transformer needed (the power supply on the chassis handles all of that). the inclusion of the earth ground pin I assume is because you can tap your power source from something not inside the cabinet... where the game manufacturers ordinarily had their own earth ground that clips to the monitor frame.

you'll also observe that Line and Neutral are clearly defined on these, because there's a hot and a neutral pin coming out of the wall outlet. with an isolation transformer there's actually no polarity because the transformer is made to eliminate neutral. which is why you normally see 2 black wires on a chassis that requires isolation, not different colors.

if you're using a screw terminal power supply you'll almost always notice a ghosting effect in the picture with the earth ground hooked up. that's why it's somewhat fashionable to run these without them. you CAN run an earth ground and eliminate the ghosting by using a piece of wire to bridge the earth and logic grounds on the power supply. if Buffett endorses no earth ground, then well... but I've read other horror stories of things that can happen without them.

you don't necessarily need to tap it into the middle pin on the power plug. you can get away with clipping it to the frame like before.
 
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