Tried to install Floppy drive, and power supply fails?? 2

[Psyke]

Hey guys.

My Pc is a HP dc7100 Series. The workstation didn't come with a floppy drive installed, so i took it upon myself to install one.

Anyways i plugged in an OLD floppy drive, connected the ribbon cable and connected the power to the floppy.

And tried to boot..... The LED lights flicker, and the CPU and power supply fans run for about 2 seconds, then everything shuts down. After disconnecting the floppy totally the same thing happens.

I swapped out the power supply, and got my system running again.. I tried the "faulty" power supply on another pc and it gives the same results..

Question is how did i manage to kill the power supply? It shouldn't have been from installing the floppy...

Anyways, comments/ideas are welcome..

Just curious as to what the hell i did to cause this..

Thanks!

 

[KevinADC]

does the floppy drive work with the new power supply? It could have just been coincidence that the power supply took a dump when you tried to hook up the FD.

 

[garebo]

Unfortunately, you can kill a power supply if the cable isnt on perfectly right. You have the wrong voltage going to the wrong place. And that does happen a lot and sounds like what happened to you.

Does the floppy drive work now?


Good advice + great people = tek-tips

 

[Psyke]

Ok, thanks for the replies.

I've put the old floppy away for now, i dont wanna chance toasting another power supply..

Should it matter, that its an older floppy? If i order a specific floppy drive for this computer model type from Hp, aside from it fitting perfectly would it make a difference at all?

Again, i haven't tried attaching the floppy to this new power supply, i REALLY don't wanna get burned again here.

Thanks again guys.

 

[garebo]

Smart decision on that.

No, you should be able to get any floppy that is 3 1/4 size to fit in a 3 1/4 slot. They havent changed, a floppy drive from, say, a Pentium 1 or 2, will work on a P4 pc.




Good advice + great people = tek-tips

 

[Psyke]

Thanks again for your replies.

I was 99% sure on the Floppy drives not making a difference, but just wanted to make sure.

That being said, i'm still scratching my head as to what went wrong here... I've worked in IT for just over a year now.. (Still relatively green, but learning new stuff all the time!)

And i've installed countless floppys, cd/dvd drives and memory and the like, and ive never had a new power supply (only had it for 4 days!) decide to go belly up before..

Hah, of course it happens on MY workstation too!

Could it have been the way, i connected the cables? could it have been an OLD floppy ribbon cable?

Still scratching my head here, but at least my machine is back and running...

 

[BaudKarma]

Sounds odd to me. I can see how a bad cable or floppy drive would cause your power supply to blow up, but it wouldn't be easy. The fact that this was the first time you cracked open the system to do any work on it makes me think it's a problem with the power suppy.

Just the basics, did you perhaps accidentally nudge the voltage selector switch? Got any strange charred/burning odors coming from it?




I try not to let my ignorance prevent me from offering a strong opinion.

 

[Psyke]

Good point, about the voltage switch.. However this power supply dosent have one.

And no there wasn't any charred/burning of any kind, the fans would just spin for 2 seconds then stop... However if i held down the power button, the fans continue to spin continously (at a low speed) but the machine would still not boot.

Again, i've got my machine up and running by swapping out the power supply for a working unit.. And i've ordered a replacement unit from HP.

So all is well, just still wondering what i did to cause this.. (So i won't have this headache again in the future.)

Thanks for the ideas / info.

 

[KevinADC]

Check the power connector that plugs into the floppy and see if there is any damage to the insulation or anything that just looks like it might not be good. Make sure you are always grounded when working on the inside of a computer or handling sensitive equipment.

The ribbon cable would not damage the power supply as far as I know. The power cable might but it would have to be a dead short. And even then there is a fuse inside most power supplies, did you check the fuse? Sometimes they are soldered in unfortunately, making them difficult to replace.

I'm leaning to coincidence here. I've hooked up a few floppies wrong over the years and never killed a power supply, but I have had power supplies that were working, I shut down the computer, and the power supply no longer worked when trying to restart the computer. I was a field repair tech for a few years and this happend a couple of three times to computers that were on for extended periods of time, 3 to 6 months, without turning them off. The power supply worked but would not restart once shut off. I never tried to figure out why since it was cheaper and faster to just replace the power supply.

 

[edfair]

If you hook up a floppy power connector off by 1 pin you end up with either 12 or 5 shorted to 0 and the power supply should crowbar shutdown before it does any damage.
The crowbar is almost instantaneous, with maybe half a turn of the fans.
2 seconds of power before it shutdown sounds more like an internal problem with the PS that just happened while you were working on it.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[garebo]

I cant remember offhand the exact voltage in each wire, but i can tell you if you put the power connector on wrong from the power supply, or something gets grounded or shorted right around that area while you are working on it or installing it in the cage or bracket. Sometimes the breadboard hits something, lots of things can happen. Thats what i was referring to. And its happened to me, i shorted out a hard drive that way.



Good advice + great people = tek-tips

 

[edfair]

You really have to work to short out a hard drive by installing tha AMP connector backwards. But it can be done. Makes the most interesting white noise while it is self destructing.
The 3.5 floppy molex connector carries 12 on one end and 5 on the other with the 2 centers at 0. Offsetting 1 pin shorts one supply to 0. Installing it upside down, which takes some effort, shorts the 5&12 lines together.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[garebo]

edfair, thats not what i did. What happened was that i was testing so i didnt have the drive in the slot, just sitting near the case. Somehow it got nudged and the pcb board on the drive touched the steel edge of the case, that was the end of that pcb board. I later got another pcb board and repaired the drive.



Good advice + great people = tek-tips

 

[edfair]

Understand. I keep some of the cardboard boxes that seagate drives used to come in for insulators when I have drives loose on top of the cases.
And in those cases where the drives are loose in the cage I keep several cardboard squares available.

Ed Fair
Give the wrong symptoms, get the wrong solutions.

 

[garebo]

Thats a great idea. I have a few little "covers" i made out of that foam stuff you can buy to line your cupboards or put under a rug so it doesnt move around. It was there so i used it. So it hasnt happened again to me.
It was only an older, well-used 3.2 gig hard drive but im so cheap i cried for a week, lol.


Good advice + great people = tek-tips

 

[BaudKarma]

I just reread this thread... if that power supply is just a few days old (or is it the whole computer?) I'd take it back for a refund. Don't mention the floppy drive, just tell them you went to power your system up one morning and nothing happened.

I try not to let my ignorance prevent me from offering a strong opinion.

 

[Psyke]

Its the whole computer that is a couple of days old, but i got a replacement power supply from HP and everything is stable now..

Still haven't tried to install a floppy yet, i'm kind of leery about trying one of these old dinosaur floppys i have lying around..

I'm likely going to order one specific to this computer model..May not be for awhile though. I'll let you guys know how it turns out in the end.

 

[KevinADC]

You're lucking, opening the case of a new computer can invalidate the warranty. Good the hear HP didn't give you a hard time about it.

 

[micker377]

Will your case accept a standard floppy? Some cases have special mounting, or the floppy has to have the faceplate removed or the "eject" button made longer/shorter to fit.

 

[garebo]

I wouldnt be too worried about installing an older floppy.
And i dont think this was mentioned but you could have installed it wrong at the motherboard. Sometimes the "red" mark on the side of the floppy cable isnt too obvious or its not installed right. YOu have to do it so that the red mark on the side is on the same side as the ide cable, usually on the right, That puts pin 1 on pin 1 for ide and floppy.
And the power connector from the power supply onto the floppy should slide on nice and easy or its not on right. The red mark on the side of the floppy should be beside the red wire on the power connector for the floppy.
like this:

yellow black black red space red line on side of floppy

ide (red) - red mark on side of cable here on right
ide (red)- red mark on side of cable here on right
floppy (red) - red mark here on the right.

Really, you can use any spare floppy. Usually with HP you have to take the faceplate off the floppy but they are totally generic as far as wiring. I just hate to see you spend money you dont have to.
If you should have any probs, it appears you would know to perhaps just play dumb, dont mention you tried installing anything, lol.
Also, dont forget to enable floppy in the bios as it wont be enabled.










Good advice + great people = tek-tips