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switching Power Supplies_dangerous?

By maxpain ·

I want to switch power supplies to see if one of them causes the problem with my PC, but I'm not sure how relevant the differences of this 2 power supplies are.

PS 1: JNC Computer Corp. Switching Power Supply
Model: LC-235 ATX
(the one that might be defect, worked on a Intel PIII 700MHz/FSB 100 system)

Input: 115V/230V~ , 6/4A , 60/50HZ
Output: 235W

+ 3.3V = 10A
+5V = 19A
+12V = 8A
+5VSB = 1A
- 5V = 0.5A
-12V = 0.5A

PS2: EC Model: 200X/250X
(the one that's surely ok, worked on AMD Athlon 650 MHz Abit K7 Pro mobo)

AC Input: 200~240V, AC 3.5A, 50/60HZ
DC output 200W: (there is a mark beside "200W" so I think the label with the specs was made for 2 models, 'cause there are also details on "DC output 250W")

+ 3.3V = 12A
+5V = 20A
+12V = 6A
- 5V = 0.5A
-12V = 0.5A

the details for "DC output 250W" are:

+ 3.3V = 14A
+5V = 22A
+12V = 9A
- 5V = 0.5A
-12V = 0.5A

I don't know if the details above are of any use to you, I added them to make sure you know everything about the power supplies that I could find out.

I'd like to know if I can use the PS2 on the comp whre PS1 worked.

thx in advance, perhaps there are some technicians out there who know such stuff.

best regards,

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be careful

by cul8rm8e In reply to switching Power Supplies_ ...

i accidently switched supply, well all went ok for a split second then BANG, well the rest you can imagine.

good luck

if there aint a problem dont try to fix it.

what is the initial problem?

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the initial problem

by maxpain In reply to be careful

I'll copy-paste this for you as I've already asked for help somewhere else.
The problems started as the comp (without any hardware changes) started to turn itself off within 1-5 seconds after booting. So I got no beeps, but the power supply seemed to be ok since it gave power for all the HD's and fans - at least for a short time.
Now I thought that'll be the mobo. So I got a new one.

I dunno which mobo I had before, but my present configuration is:

CPU: P III 700MHz/FSB 100
mobo: Socket 370 Gigabyte GA-6VTXE
Video: NVIDIA Riva TNT2 Model 64 / Creative Labs CT6939 RIVA TNT2 Value
Sound: YAHAMA Corp YF724F DS-1 Audio
1x DVD-Rom
1x CD-RW

After 2 hours of putting it all together the problem is still there. It got even worse... sometimes the comp won't boot at all (no power) sometimes it boots like it did before: ~ 1-3 seconds power, then the comp turns itself off.

There is no dust, I checked the CPU and the CPU heat-sink/fan works and its fitted correctly as far as I can say (it's cold and it touches the CPU). I tried to remove the soundcard leaving only the 3D-card. All cables inside the comp are securely seated, I've also replaced the computer's electrical cord. Searched the mobo for metal pieces that might be touching other metal pieces (forgotten screws, etc.) All this to no avail.

Any ideas why the comp turns itself off so shortly after boot? What could possibly cause this?

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by maxpain In reply to the initial problem

after posting this I:

- put the CPU out and back again (the fan is touching the CPU chip so from my point of view I couldn't have done something wrong here)
- tried another Power Supply
- checked the wiring of the power cable that's connecting the power button of the case with the mobo (unfortunately I have no such spare cable to check if this one isn't working properly, but from the outside the cable seems to be ok, nothing damaged, after all I can turn the PC on for a few seconds, which means that the cable iself should be working... i guess)
- tried another RAM module
- unplugged all power cables leading to the 2 CD-ROM's the Floppy and left only the system fan, the HD and the mobo of course :) then tried to boot again... same thing.
- I also checked the wiring of various Power LED cables of the case (HDD LED, Power LED, Speaker.. etc.) just in case, and they do work also.

well.. what 'd you think of all this? Can someone help me out here? Any more ideas of what could cause the bootup failure?

If it is the CPU I can't test it, without buying a new one or paying a lot of money checking the hardware again, even though they will check also all the things I already checked and demand money for it

I'm kinda desperate...

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by pollard In reply to the initial problem

Try unplugging the floppy, DVD and CDROM. boot the system with a minimum of non-motherboard based hardware.

If this works, add one interface at a time. When it stops working, remove the last one added, then
add the others- still one at a time. If everything
works, you've identified the problem unit.

I had a similar problem due to a short in a floppy... It eventually damaged a voltage regulator on the mobo. CPUs and memory still tested out fine. Adding the extra peripherals caused the mobo to turn off....

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by crapaud ergo sum In reply to the initial problem

Assumptions always seem to leave something out so?

At what point during boot does it turn off?

If video does display is it correct?

Have you tried to enter bios during boot?

Have you jumpered a reset for the bios or removed the battery?
I have replaced two power switches for weird problems, that however is a long shot.

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