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Compaq Portable I Floppy Drive COntroller 601 Error

brain

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After buying a dual floppy (looks original inside) Compaq Portable I (but, I'm not an expert, so don't shoot me if I'm wrong :) at VCF East a few years back, trying to boot it, failing, and stowing it away for a better time to diagnose, I finally pulled it back out and started debugging.

Unit boots to a 601 error (FDC error). I have removed both drives and successfully booted MS-DOS on another machine with those drives (and a fresh 260kB disk), so I know the drives are good. Thus, I suspect the FDC is bad. I have read that an IBM PC FDC will work, so I found a used tested on and it is coming. That said, I think it is worth trying to get this FDC fixed:

  • Is there some specific component that often fails on these units? The drive lights up, so some of the signals are making it, but no track to track movement, if that helps
  • If not, is there someone around who would fix the card for a fee? I am out of my element and would much prefer to pay someone to bring the card back to life, or at least test it and ensure it is working
  • Failing either of those two options being reasonable, is there a replacement FDC I should look for? I don't know that I need this unit to be vintage pure, so am happy to replace portions with items of usefulness.

Jim
 

SomeGuy

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I'd consider it a little unusual for the floppy controller card to die.

Check that the ISA slot is OK. It should fit in another slot if you can get the cable to reach.

Also, check the floppy cable. If it was previously owned by an enthusiast, it might have been re-assembled with an incorrect or damaged cable. (I forget off hand, but I think that uses a twisted instead of flat cable?)

Perhaps check the dip switch setting on the motherboard.

I think an IBM PC FDC should indeed work, although those have a different style connector. If another ISA FDC works fine, and the cables test OK elsewhere, then that would point squarely to the controller.

Any low density ISA FDC card should be fine as long as it fits in that slot and the cable reaches.

If you wanted to add a 1.4mb drive, you could add an 8-bit high density controller. (Might need to check the motherboard BIOS in case it is an early version).

As far as repair, you might first ask around and see if anyone has an extra one of those. Broken Compaq Portables get parted out periodically.
 

Nevets01

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I think an IBM PC FDC should indeed work, although those have a different style connector. If another ISA FDC works fine, and the cables test OK elsewhere, then that would point squarely to the controller.

Any low density ISA FDC card should be fine as long as it fits in that slot and the cable reaches.

Can confirm, I use an IBM PC low-density controller in my Compaq, in order to have the external floppy connector.
 

brain

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I'd consider it a little unusual for the floppy controller card to die.

Check that the ISA slot is OK. It should fit in another slot if you can get the cable to reach.

Moved it to another slot. Same issue.
Also, check the floppy cable. If it was previously owned by an enthusiast, it might have been re-assembled with an incorrect or damaged cable. (I forget off hand, but I think that uses a twisted instead of flat cable?)
Used a different cable from my FD cable box. Still same error
Perhaps check the dip switch setting on the motherboard.
Checked. 2 drives, all other switches are correct.
I think an IBM PC FDC should indeed work, although those have a different style connector. If another ISA FDC works fine, and the cables test OK elsewhere, then that would point squarely to the controller.

Any low density ISA FDC card should be fine as long as it fits in that slot and the cable reaches.

If you wanted to add a 1.4mb drive, you could add an 8-bit high density controller. (Might need to check the motherboard BIOS in case it is an early version).
Seems like a late version, as it only has 1 set of switches.
As far as repair, you might first ask around and see if anyone has an extra one of those. Broken Compaq Portables get parted out periodically.

Will do.
 

ldkraemer

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REF:
http://www.vcfed.org/forum/showthre...ng-a-IBM-5150-601-code-at-POST-Need-some-help

Along with the above suggestions, are the switches on block 1 switches 7 and 8 set correctly for each configuration you are trying?


Switch 7,8
ON,ON = 1 floppy drive
off,ON = 2 flops
ON,off = 3 flops
off,off = 4 flops

Also, check the CMOS Battery.
About three hours later… Being the only removable part left, I figured I remove the CMOS battery and check it while I’ve it
remove. Turns out it’s dead. Replace it with a new CR2032 button cell and voila – system boots again as if nothing happened.


Larry
 
Last edited:

brain

Experienced Member
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Apr 24, 2009
Messages
148
Location
Iowa, USA
Switch 7/8 are set correctly. I don't see a coin cell or other battery on the COmpaq Portable I motherboard.
 

brain

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Location
Iowa, USA
IBM PC FDC came, and unit boots, so it's the COMPAQ FDC. I'll do some searching for a Compaq FDC to replace.

Jim
 
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