How to test an ATX Power Supply? + Misc.

[Bob-NB]

I've got a problem with a "dead" computer. It has ATX power supply.

When I attempt to start the computer, it does nothing, just as if there was no power to it at all. All connections to the computer have been checked and also tried with a different power cord.

Since ATX power supplies start with the case switch powering through the board to run, how does one test the PS to see if its working?

Can you unplug the unit from the mobo and jump across a couple of the wires to test the unit by itself?

I do not have access to another ATX power supply to test by switching the units.

With AT cases it is very easy to check, since they have a direct power on switch to the PS.

The problem arose when the guy pulled a PCI modem card without powering down (its a long story). The computer simply shut off.

Now I'm trying to see if he fried the mobo, or if its just a PS problem, but it's completely dead.

If its not the PS, are there any "fuses" or relays on the mobo that can be checked? I don't see where there is any electrical damage on the board itself. (I could see the damage from a lightning strike on my bro-in-laws modem card earlier this year, but it did not hurt the mobo on a previous repair job on a different computer)

The unit is a P11 450 HP 8396 with what they say is a "Leopard" motherboard made in taiwan. I'm sure its made by someone especially for HP since I can't find the manufacturer nor the specs on the board other then the limited specs from the HP site.

Since the board is "tatooed" by HP, if I have to replace the board, none of the recovery disks (including the HP win98 special set-up) will be able to be re-loaded.

Any help would be appreciated.

(Since this post covered covered two topic areas I was unsure where to post)

[bdog]

There are two wires on the conector that goes from the ps to the mobo that you can jumper that will turn on the ps. I am NOT sure which ones they are, but if I remember right they are the two green wires near the middle of the connector, but you had better wait to get someone else to confirm this, or until I can look it up again to be sure. I don't have the book o it here at home, but I will check later at work.

[kwai]

i'd like to know which pins on the mb connector to "short" too. the info has been on this BBS before, but i couldn't find it by searching.

anyone? anyone?

make sure you charge that guy a lot of money -- its high on the user stupidity scale.

[800XL]

Just an FYI, that motherboard is likely made by Intel. 'Leapord' sounds like it would fit into their board naming scheme. If you want/need I could do some research to confirm that and maybe get a bit more info about the board.

I'm not totally familiar with HPs more recent recovery disks, but you can likely fire off the Win98 setup executable without using their bootdisk or booting from the CD. A standard Win98 Startup floppy should allow you to run setup from the cd without calling HP's batch inf files.

[Bob-NB]

Problem solved. There must be an internal curcuit breaker on the PS or on the board because when going to the bench to test it I hit the "on" switch and it fired-up and started running.

Further testing shows no apparent problems. If anyone has comments regarding the issues I raised in the post, I would welcome your comments.

Thanks bdog for your speedy reply. I welcome the information you can find on the subject.

[Bob-NB]

Thanks 800XL. Any additional information you could dig up would be appreciated.

I work on alot of HP's but there has never been a problem when changing hard drives or anything else...except if you change the mobo.

Up until now, I haven't had to do that (and apparently do not have to do now).

I too have an HP with the darn special HP win98 disc.

It's my understanding that they are not the complete win98 disc. I'm unsure what is lacking. I will play with a regular win98 start-up disc and see if I can activate the disc without the HP inf file.

Are you aware of the "tatooing" process? How do they tag the mobo so it will only run on one of their boards? I'm sure it must be somewhere in a chip on the board.

It seems totally unfair to pay for all the programing (of course included in the cost of the computer but at what I'm sure are nearly give away prices)and then not be able to use that same software if you were to change the mobo.

HP wanted about 390.00 for the new board and about 325.00 for a re-built board....simply outrageous!!!!

HP support even told me that the replacement board would not be tatooed and that I would have to take it to an authorized service center to have it done to work with the recovery discs. They must be crazy.