Question about Arcadeshop MCR Power Supply Conversion

nocashvalue

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Question about Arcadeshop MCR Power Supply Conversion

I've got a question about the arcadeshop MCR power supply conversion kit. I've used the kit before with no problems on a Spy Hunter. However, when I tap into the monitor power on my Tron, the lowest my +5 can go it 6V which is too high. I've tested it with a load and without a load on the +5.

I would say the Happ switching power supply I used was bad, but it is brand new and I tried another brand new one and a used one both with the same results. I confirmed the power supplies themselves as good by hooking them up to another power source.

Where can I hook in to power on a Tron so I don't get this whack reading? I don't want to fry my board. Thanks!
 
I was lazy one day and hacked it into my interlock switch on the back door. (I've been meaning to move it)

Now I haven't tested the voltages (looks like I may need to) but it runs fine, and I've had it on for hours.

The drawback of this is the game has to be unplugged to be truly off. I notice the game gets power but the monitor isn't on if I have it plugged in, the way I wired it.
 
Your isolation xformer could be upping the input voltage

No reason to use it for the switcher, just wire it to your 110vac before the transformer and after both switches (like the input side of the xformer)
 
I've tested it with a load and without a load on the +5.
With a typical switching power supply it's invalid to measure the voltage without a load. Without a load it cannot regulate the voltage properly the value will drift high. Recheck your belief about the voltage not adjusting with a load properly connected (ie. the PCB).

Where you're pulling the AC from will have no effect on the value of +5v. It's not ideal to pull from the monitor wires because that puts unnecessary extra load on the monitor's transformer, but it should still work fine.
 
Furthermore, yer not supposed to power a switcher (or anything else) off the secondary of the iso xfmr. *Just* the monitor. From the primary is fine, but you need to up the fuse in line with the primary so it doesn't pop with the extra load on that circuit.
 
most modern switchers have an isolation transformer built into them.
 
Just tossing this out......did your meter (maybe) lose calibration or low batteries.

Edward
 
THIS!!!!!

Nailed it. New batteries showed proper voltages. Hooray!

Do yourself a favor and throw that meter in the trash, and spend the bucks to buy a nice one. I used to use cheapies too but I got burnnnnt.

Imagine if your meter would have said everything was 4 volts, and no matter how HIGH you turned the knob, you couldn't get it over 4 volts. You would have sent 6.5 or so to the chips and possibly fried half of them.

Flukes stay the correct reading right up until they won't turn on anymore... I've heard most of the 30 dollar or so ones are good too, but I don't have one, I just bought a used Fluke.
 
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