The Two Iso Wires... - Does it matter which way they go?

Thomas

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The Two Iso Wires... - Does it matter which way they go?

I built this power center today. It doesn't have all the bells and whistles but will do nicely for my new Burgertime project. On the top of the transformer I have...

Left Side: OV
Right Side: 115V 1Amp

Does it matter which way those two wires go to the monitor?

Side note: What does OV stand for?

Thanks
 

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Nice work. Looks good.

I notice your isolation xformer is rated for 1A. This should be fine for any 19" CRT monitor I've seen, but larger monitors might draw more than that. You mentioned a Burgertime... I guess it's not real likely you'll be putting a 25" in that, but just thought I'd mention it.
 
Zero Volts, Thank you.

One more question please...

The adjustment knob on the switcher. Can you explain how to get that dialed in with my meter the correct way?

My jrok is acting a little funky...

I did search for terms like

Switcher adjustment, Dial In Switcher, Power supply adjustment. I know I have see this before but my search nets nothing.

Thanks
 
The adjustment knob on the switcher. Can you explain how to get that dialed in with my meter the correct way?

I'd recommend placing your meter leads on the GND and +5VDC lines ON THE PCB. Maybe the traces just inside of where the edge connector sits. Adjust PS knob to make this about 5.1V or so. Different games may be more/less sensetive, and different people may have slightly different "target" values, but 5.1 seems as good as any for starters.

If you want to get fancy, you might check the power level at a few ICs distant from the edge connector. If they're dropping much below 4.8, you might need to crank up a little more. Generally, TTL ICs are rated for operation between 4.75 and 5.25VDC, so you shouldn't crank the input up beyond 5.25, and you don't want the far end to lag below 4.75. That said, most ICs will happily operate outside of the spec range... that's just the "guaranteed" operation range.

After you've got it adjusted for proper PCB voltage, you might go back and see what the output AT THE POWER SUPPLY is. If its much higher than what you just set the PCB to, you have bad/old/dirty connectors. How much higher is too much? Heck if I know, but I'd probably be concerned if it was a volt or two (or more) higher.
 
Nice work. Looks good.

I notice your isolation xformer is rated for 1A. This should be fine for any 19" CRT monitor I've seen, but larger monitors might draw more than that. You mentioned a Burgertime... I guess it's not real likely you'll be putting a 25" in that, but just thought I'd mention it.

Thank you... I just copied from another one I have.

However I am glad you said something about 1A for 19 inch monitors. I have this old pit-fighter power center that I am gonna clean up and bolt it to another square of plywood.

This one ran a wells 25 inch so it should be good to go for my Nba conversion.

This thing needs some paint...
 

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I'd recommend placing your meter leads on the GND and +5VDC lines ON THE PCB. Maybe the traces just inside of where the edge connector sits. Adjust PS knob to make this about 5.1V or so. Different games may be more/less sensetive, and different people may have slightly different "target" values, but 5.1 seems as good as any for starters.

If you want to get fancy, you might check the power level at a few ICs distant from the edge connector. If they're dropping much below 4.8, you might need to crank up a little more. Generally, TTL ICs are rated for operation between 4.75 and 5.25VDC, so you shouldn't crank the input up beyond 5.25, and you don't want the far end to lag below 4.75. That said, most ICs will happily operate outside of the spec range... that's just the "guaranteed" operation range.

After you've got it adjusted for proper PCB voltage, you might go back and see what the output AT THE POWER SUPPLY is. If its much higher than what you just set the PCB to, you have bad/old/dirty connectors. How much higher is too much? Heck if I know, but I'd probably be concerned if it was a volt or two (or more) higher.

Thanks for taking the time Darren to hammer all that out. I am up to speed again on the power. You know when you don't do this for a living or old or burnt or all the above. Its easy to forget this stuff.
 
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