Restored floppy drive, made diskette copies of my images, IMLed the 3174 from floppy

 RESTORING THE 1.2MB 5.25" FLOPPY DRIVE FROM MY 3174

The Hitachi floppy drive used in my 3174 controller is installed in a plastic enclosure that in turn is bolted into the drive frame in the controller. I removed the drive, then opened up the enclosure to remove the drive mechanism.

Hitachi 1.2MB drive in IBM plastic enclosure

I carefully inspected the mechanism and the PCBs for signs of wear or damage. I applied +5 and +12V carefully to check for issues with the power supply, regulators or other circuitry. Everything looked good. I next used alcohol wipes to carefully clean the heads, as well as verifying smooth movement of the head assembly from track 00 to 79. 

Bottom of the drive

Top of the drive mechanism

At this point I checked for correct operation when a diskette was inserted - permitting the lever to rotate and pushing the drive clamp and heads onto the magnetic surface. That too worked well so it was time to place the mechanism in the plastic enclosure and mount that back into the 3174

Testing the mechanism with media inserted

BUYING APPROPRIATE MEDIA FOR THE DRIVE

The 1.2MB drives require a specific floppy media - double sided high density - in order to achieve the data density. I found some New-Old-Stock (NOS) media on eBay and had it ready to write diskette images onto. 

Polaroid NOS media

USING UTILITIES TO COPY THE GOTEK IMAGE TO THE PHYSICAL DRIVE

I had the real floppy drive cabled into the drive 1 position and one of the Gotek emulators cabled as drive 2. I set the Gotek to mount the Utility diskette image and IMLed from drive 2. This gave me the utilities menu.

Choice 3 is the Copy utility, which supports a range of copy activities include a fully disk to disk copy which is what I wanted. It will format a diskette as it writes, so no prep was needed for my new media. I told it to copy from drive 2 to drive 1, changed the Gotek to mount the Control image and let it rip.

The copy utility started at track 79 and worked its way down to 00 rather quickly and silently. In the picture above you can see the Gotek LCD peeking out in the upper slot, where it showed the track being accessed. The physical drive is lit as it has just read a track from the Gotek and was writing its contents to the same track number on the new media.

Copy utility doing full copy, currently on track 62

TESTING IML FROM THE FLOPPY DRIVE

After having copied the Control diskette image to one of my new floppies, I started a new copy and wrote the Utility diskette image to a second floppy. These sit in the tray on the controller in between the positions for floppy drives 1 and 2. 

I hit the IML button on the controller, which causes it to attempt to IML from images starting with drive 1, then drive 2, then the hard drive if it exists. Since the Control floppy was mounted in drive 1, that began reading and the controller completed its boot sequence and self tests, ending about two and a quarter minutes after it began with the magic status number 3174 displayed on the front panel.

This is a video of the 3174 doing an IML from the floppy, continuing through all its configuration and self test before it becomes fully operational, which is indicated by the code 3174 displayed on the front operator panel. You can see a 3178 terminal attached to the controller running the online test here.