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And then it went POW!!!

C

Chromedome45

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So here I was trying to make a standard floppy work in my Model 70. Well I had made the cable and soldered on a 34 pin header onto a 40 conductor card edge connector from a butchered old ISA card. I soldered on a 3-1/2" power connector to pins 40 for 12 volts and pin 38 for 5 volts and the 2 ground wires onto pins 37 and 39. I then ran a length of 34 pin ribbon to from this connector to the floppy drive. Everything looked good so I hooked up the card edge to the drive "B" side of the floppy/HD riser and powered up the computer. After about 2 seconds I heard a loud pop like something blew. I'm think oh crap there went the power supply. So I take it out open it up and check fuses. Of course there good so I check voltages. All good there to. Some now I'm shaking real bad. I removed the drive platfom (Not sure the actual name but I think you all know what I mean) and start
looking around the motherboard. Well I see this big chip with part number 72x8299 with a hole blown in it. Kinda like the asteroid that killed the Dinosaurs. Well it turns out that this chip is the I/O controller. Well as you can guess the motherboard is now toasted. So I look on ebay and find a 25Mhz version of the board and went ahead and got it. Well now I'm wondering what I did wrong with my cable. Well it turns out that one of the feed through hole on my ISA connector was shorted to one the the control lines on top of the connector. Motor on I think shorting it to ground. Moral of my story is get the right part if you can so ya don't kill your computer. :) Attached picture is of replacement MOBO.
 

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Do you still have the old dead model 70 floppy?

I am thinking about ordering capacitors to redo 4 or so of my PS/2 floppy drives and will have some extra if you want me to redo one of yours. These are the ones with the big square eject buttons (seems like they are different for newer machibes in the PS/2 line).
 
I did the same thing to an old P1 HP Vectra. I got one of those $3 POST cards that come with instructions that say you can plug it into an ISA slot backwards and it won't hurt anything?

Don't believe it! I tried that and turned the nice white lettering on the southbridge chip brown. Most expensive $3 I ever spent.
 
i've had something similar to this happen. was trying to make a cable for a 2.88mb floppy that drew power from the cable aswell as date. I forgot to cut the line leading to the MB that the 12v was going to. smelled really nice. i got lucky with it though, it only took out the floppy controller part of the super i/o chip. a week later i found a 2.88mb with data and power cables. still have the drive, still cranking out custom boot disks for it..
 
Chuck(G) said:
I did the same thing to an old P1 HP Vectra. I got one of those $3 POST cards that come with instructions that say you can plug it into an ISA slot backwards and it won't hurt anything?

Don't believe it! I tried that and turned the nice white lettering on the southbridge chip brown. Most expensive $3 I ever spent.
Click to expand...

I tried it once, just kept the AT PS from switching on (means something is shorted I asume).
 
My original floppy is still good I think. I should get the replacement mobo by Friday to test it out. My little experiment was trying to make a "B:" floppy drive. :) And in my opinion I think with a short like that the PS should not have received a power good and should have never even powered on. Blame it on IBM I guess.
 
The Amstrad PCWs take 3.0" floppy drives. The power connector to them is identical with a standard 3.5" power connector, but the +12 and +5 lines are interchanged. Yep, you guessed it--I toasted a 3.5" drive but good.
 
Decided to upload a picture so you can see what happened. Nice crater there :) excuse the blurry picture.
 

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