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Microsolutions Backpack 5.25" External Parallel Floppy Drive - Immaculate condition

halp said:
Does it support 8" drives? I am looking for good way read old 5.25 and 8 inch media in either DOS or Windows. Have a few ISA/PCI motherboards and bunch of 8 inch drives I think still work.
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Hi, halp,

Sorry: what does 'it' mean? Not sure what you're seeking. If you already have the media and the drives, you can probably find an old Radio Shack computer in which to mount them. If my memory is accurate, I remember doing word processing on a old Trash-80 with one 8" internal drive that was side (vertically) mounted.
 
The Backpack does support 8" floppies. I believe that I posted some source code for a real-mode BP driver some time ago. This was the result of some very tedious reverse-engineering.
 
Chuck(G) said:
If you need a parallel 5.25" backpack (for use, not just to have something pretty on the shelf), you can take a standard 5.25" drive (or better yet, a dual 3.5"/5.25" drive)), supply your own power supply to the drive and connect it to the board from a 3.5" Backpack and use it that way. Every Backpack floppy drive has a NVRAM/EEPROM on it to hold configuration information for up to 4 drives. Simply use the SETID utility that comes with the drive and add the command-line switch "/DRIVETYPE".

Bingo--you're in business. Supply your own 5.25" enclosure.
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I've been looking for the 5.25" floppy drive adaptor unit for my PS/1 for about 20 years and have finally sourced one. Woohoo!
 
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Does anyone have the info for the power supply of this drive? Polarity and output voltage and power/amps?

I have the same drive - minus power supply - and need to use it fairly urgently. There is no info on the inside or outside of the casing so I guess it must all be on the supply itself...

Thanks
 
There are at least 4 versions of this drive. The latest take a 5VDC power supply; earlier ones take a 9VAC; still earlier ones take something like 13.8VAC. To be 100% sure, you have to look at the innards, if you can't find any voltage rating on the outside.

Opening one of these things is a little tricky. But fear not, there are some ways around the problem.

  • If it's an all-metal-cased unit with a permanently attached cable, either a 13.8VAC or 9VAC power supply will work, if it's a 3½" unit. If it's a 5¼" drive, you need the 13.8VAC supply.
  • If it's a plastic-housed 3½" drive, look at the back plate, near the power switch and power connector. If, slightly above and to the left of the power connector, there's a screw head, you need a 9VAC power supply.
  • If, instead you see a hole in the aluminum plate, not filled with a screw, you need to use a 5VDC power supply.

As far as the ratings, if you've got a 5¼" unit, you should have at least a 1200 mA supply current. The 3½" units will work fine with 800 mA. The 5VDC supply is 1600mA with center pin positive/shell negative.

Hope this helps.
 
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Chuck(G) said:
There are at least 4 versions of this drive. The latest take a 5VDC power supply; earlier ones take a 9VAC; still earlier ones take something like 13.8VAC. To be 100% sure, you have to look at the innards, if you can't find any voltage rating on the outside.

Opening one of these things is a little tricky. But fear not, there are some ways around the problem.

  • If it's an all-metal-cased unit with a permanently attached cable, either a 13.8VAC or 9VAC power supply will work, if it's a 3½" unit. If it's a 5¼" drive, you need the 13.8VAC supply.
  • If it's a plastic-housed 3½" drive, look at the back plate, near the power switch and power connector. If, slightly above and to the left of the power connector, there's a screw head, you need a 9VAC power supply.
  • If, instead you see a hole in the aluminum plate, not filled with a screw, you need to use a 5VDC power supply.

As far as the ratings, if you've got a 5¼" unit, you should have at least a 1200 mA supply current. The 3½" units will work fine with 800 mA. The 5VDC supply is 1600mA with center pin positive/shell negative.

Hope this helps.
Click to expand...

Thanks very much for the above - mine is a all-metal-casing 5.25inch drive, model number 1231, serial 31219483. So I guess that means 13.8VAC supply..?

Is it definitely AC input though?

I guess that may be why no polarity is on the power input pin - I just don't remember using AC inputs directly into these things!

Thanks again for the help.
 
It's easy enough to open the casing--4 screws on the sides. You'll see a small PCB with a heatsink and a TO-220 voltage regulator on each side of it.

The reason for AC input on the earlier Backpacks is that both a 5VDC and 12VDC supply is necessary to run 5¼" drives and some 3½" drives. The easy way to do this was to put a bridge rectifier and two voltage regulators inside the metal box rather than inside a wall wart (better heat dissipation as well).

13.8VAC should be a minimum; you'll probably be okay up to about 15VAC without things getting too warm. It's the I²R losses in the 5V regulator that creates most of the heat.
 
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