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Power not supplied

By LBSmusica2 ·
I guess it is back to the 533MHZ CPU 256MEG ram,Via Chipset,dual cpu support,Tyan S1854 Trinity 400 motherboard.It has a PPGA-370 Intel Celeron processor,ATX form factor and supports 8.4 gig and higher. The power supply was a power switch on front and on off switch in back it's gone,was 300 watts. I purchased an ATX power supply,inserted it, turned it on and no power.I purchased it from where I purchased the computer.They know me and my machine.I returned twice because of no power.There is no back switch.All pins are on the way they were before.

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Power not supplied

by arichart In reply to Power not supplied

This is probably already been looked at, but are the jumper settings for the power (LED, reset, etc.) in the correct places?

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Power not supplied

by LBSmusica2 In reply to Power not supplied

You see,when removing a power supply,there is no need to remove the front casing or the button switches from the board.

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by LBSmusica2 In reply to Power not supplied

Poster rated this answer.
Yes all the pins are indeed in the right places.Pinouts are:1,3 HD LED,2 POWER LED and 4 SLEEPLED,5 GROUND and 6 POWER ON/OFF,7 RESET and 8 GROUND.PIN 13 can be used if a 3 pin bicolor is available with power led.1,3,5 odd top,2,4,6 even is bottom.

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Power not supplied

by TheChas In reply to Power not supplied

Just for clarity, an ATX system uses a 20 pin double row connector to connect to the motherboard.
While there may be a power switch on the power supply itself, an ATX power supply does NOT connect to the front panel power switch.

Check the 120V 240V switch on the power supply, and verify that it is in the correct position.

Unless there is a power switch on the supply itself, an ATX power supply is part way on ALL the time.

There is a 5 volt standby power line that supplies power for the power control circuit and a few other functions on the motherboard.

For an ATX system, the front panel power switch is a momentary contact push-button switch that connects to the motherboard using a 2 pin header connector.

To check an ATX power supply, measure the voltage on the Purple wire (pin 9) to ground (any black wire)
With power applied, but the PC off, there should be 5 volts DC on the Purple line.

If there is no 5 volt standby voltage, there may be a short in your system that is blowing the fuse inside the power supply.

Chas

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Power not supplied

by LBSmusica2 In reply to Power not supplied

There is no need to check the old power supply it is finished.The new power supply works in another machine,but not the Tyan dual cpu machine.The hard drive blew as well with the old supply.The new supply carries the same pinout for the motherboard.The option of a 2 pin power con or a 3 pin if it had one.That was power switch on power supply back only.Not on front of machine.

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by LBSmusica2 In reply to Power not supplied

Poster rated this answer.
The 20 pin connector that connects to the motherboard fits snuggly with no signs of life,when the front power on switch is pressed.There is sufficiant power from the line that runs the 5 volt fans,but nothing works.What of reverse polarity or parity errors.Could this have happened to the board?

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Power not supplied

by sgt_shultz In reply to Power not supplied

well, the power supply is set to 110, not 220, right? does it have a fuse? does the fuse ohm out? if you just set the power supply on a bench, plugged in, with a hard drive plugged into it (becausde switching power supplies need to have a load before you can measure voltages), when you switch it on, can you measure any DC on any output pins? if so, chances lean towards power supply being ok. or, easier, maybe, can you try the power supply in another computer? if you have been thru two power supplies, i'd start looking at the motherboard instead as problem point...you getting any led's lit on motherboard? have you reseated the processor, RAM? have you taken out all cards and hard drives?
i have two dead motherboards here...the led's light up but they act just like the power supplies are dead. i know the power supplies are ok because i swap them into other pc's and they work...i have no idea how to approach troubleshooting the mboards beyond what i mentioned above so would like to hearhow you make out fixing yours...

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Power not supplied

by LBSmusica2 In reply to Power not supplied

Power supply is fine in another machine.All leads are fine as well.The day it went,I removed all items from the board and had put the board through all tests.It is fine.Maybe the Dual cpu,Riser one and the Ziff are needing more power to work.Meaningdual board.Yes it is 110-115v,no fuse.Only one cpu can be used at a time,up to 1.6 ghz.

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by LBSmusica2 In reply to Power not supplied

Poster rated this answer.
The bios has bit the big one.I sat in ahh as I watched my two year old boards bios turn black in the center.The crystal in the award bios has turned back to coal.I thought this time I had finally fix something.It seems peoples help has not been good today.I tried to set it up barebones,just the hard drive,motherboard,memory,cpu and video card.All attached to the wonder dok case it came with.The power connections were done right,the way the board read.I pluged the machine in,pushed the power button,nothing,again and saw the center of the bios blacken.I unplugged all,saaad.

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Power not supplied

by TheChas In reply to Power not supplied

Since you know the power supply works, I suspect that when the other supply went, it damaged the motherboard in addition to the hard drive.

When you start up an ATX system, the motherboard sends a signal to the power supply to turn on the main power.

If the power supply does not receive a power good signal shortly thereafter, it shuts down.

Further, 300 watts would be the bare minimum supply for a dual CPU system.
I would go to at least 500 watts.

Take a close look at the capacitors, resistors and transistors near the CPU sockets on the motherboard.
If ANY parts are bulged, charred, or singed, the motherboard is toast.

Chas

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