The Extremely Uncommon Texas Instruments Model HX5102, Hexbus 5.25" Floppy Drive (I really hate the word RARE!)
|Okay, so here's what it looks like from the front.
Not so impressive is it?
Well, it's not supposed to be. It's supposed to be a fully functional 360K DSDD floppy drive. And it is.
|The back is pretty typical for the hexbus
line of peripherals, with 2 exceptions.
1. Normally hexbus peripherals are battery powered. Ain't no way this baby is. The power supply is an 18 V AC power supply adapted from the 99/4A. More on that later.
2. There's an additional peripheral interface besides the 2 hexbus ports. It's designed for an additional floppy drive. Not sure if this will work or if it was designed to be a direct interface for the 99/8. More to come.
|I've taken the front off here. Note the steel cage above the floppy drive. This is a Faraday cage. It's designed to reduce/eliminate any EMI that might be generated by the device. This sort of set up is extremely effective, but I suspect if the drive had gone into production, this probably would've been replaced with the metalized paper we see so often inside of older computers.|
|Now here's an oddity. It's kinda hard
to see, but there's no serial number, date code, or Assembled in
indicators. However, it's common knowledge that the hexbus drives
were built in Lubbock, TX and the date was in late 1983.
I didn't take a close up, but underneath the power plug and switch, the FCC ID is blank!
|Here's a shot of the drive opened up. Note the cage around both the drive AND the circuit board. I would wager that if you were to hold an EMI detection meter right next to this thing, it would be sense hardly anything! Yep, the Texas Instruments engineers definitely knew their business. Heck, this is so secure it would probably pass military requirements!|
|The circuit board. This looks pretty much like a finished product. The drive I had many years ago was a nightmare of kludge wiring. The case was also more like a Commodore 1541 rather than the case on this unit.|
|Here's the part number and date code on the circuit board. 4083 indicates this particular motherboard was manufactured in the 40th week of 1983.|
|All the other chips on the motherboard are
pretty standard stuff. Here is the 2 chips that make this so
special. If we were to read these out and burn new images, there
probably wouldn't be too many difficulties in duplicating or even
improving upon the original system. Heck, some enterprising person
could probably update the code to allow for higher density drives like a
720K 3.5" drive. I think that would definitely solve the mass
storage problem on the CC-40.
Next step would be to reduce the size of the board and make it battery operated.
|Yeah, I know it looks ugly. What the TI engineers did was to hack a 99/4A power supply. Simply cut out the 1 upper contacts and tap only the 18V AC supply and you're good to go. It doesn't really matter which way you plug in since it's AC voltage, but it's still nice to leave the upper chunk of rubber in there as a alignment "key."|