Arcade Collecting > Merit/JVL Touchscreen

Trying to power up a Megatouch motherboard

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gio_aus:
so would i need a jumper over the PWR SW pins on the motherboard?

lilshawn:
no...because the older AT boards don't have a "soft"  switch... they just powered on when the power supply was turned on.

normally with an AT power supply, the 110 (or 220 depending) was fed into the back of the power supply where you plugged in the cord.... the line was brought OUT the front of the supply inside the computer to the power switch out front of the case where it was switched off and on with the user power switch... then fed  BACK IN the power supply and used to power the power supply with mains 100/200 volt power.

TL;DR - the power switch on an AT power supply ACTUALLY turns the power off and on to the supply.

in a newer ATX supply, it's powered all the time... even if the computer is off. this (called "+5vSB") is often used to power USB devices and whatnot so you can use them to "wake up" the computer from an off state. when the the "soft" power switch is pressed the computer sends a ground signal down the "pg" wire on the supply, and the power supply powers up the rest of the power rails (+3.3v/+5v/+12v etc) on the supply to power up the computer.

TL;DR - ATX power supplies are switched internally with a signal from the computer.

when you try and mix and match, you simply need to supply switched 120 volt power to the ATX supply (from the power switch of the megatouch) and then trick the power supply into thinking it's received the "PG" signal from the computer (by grounding the PG" line to the supply)

the harness you linked, while it will work, isn't really necessary as you already switch the power to the supply on the back of the machine.

gio_aus:
ok so just got the adapter and hooked it up to the power supply and motherboard, still no response. I know the power supply is definitely working so am I to assume either the motherboard or cpu is dead?

ed12:
u may need to soft start the mother board.
reason is because if the bios batt has been changded ? or is just flat,
your bios setting's would be knocked out

ed

lilshawn:
...but if this is an old AT board, it should just power up. no soft start here.

take a volt meter and double check you are getting 3.3v, 5v, and 12v on the orange/red/yellow wires (respectively) if the board is getting power, it should startup (barring a catastrophic failure in the past)

if the old power supply was no good and failed in a most spectacular way, it may have taken out the regulators on the motherboard, in which case, it may be junk.

double check you are indeed getting juice out there first though.

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