11/02/88 Installing a TEAC 3.5 inch, 1.44 Meg floppy disk drive Rich Skalsky 10/20/88 An excellent deal right now for 3.5 inch floppy disk drives is the 1.44 Meg TEAC FD-235HF-117. It will reliably format, read and write both 720K and 1.44 Meg 3.5 inch diskettes, is very quiet, and installation is a breeze. I am including some information in this text file which will make the installation in an AT clone or compatible a breeze. This information is only applicable for those using an AT clone, PC or MS-DOS 3.3, and a Bios that recognizes 1.44 Meg, 3.5 inch diskette drives. Since I am using DOS 3.3 and my bios is Award 3.03 which does recognize this type of drive, I can only attest to the installation under those parameters. The TEAC 3.5 inch micro floppy disk drives (often referred to as the FDD) come in 4 different models, 2 720K models and 2 1.44 Meg models. The capacities and part numbers are: Unformatted Formatted TEAC Model Bezel Capacity Capacity Number Color 1. 1 MB 720 K FD-235F-100 Black 2. 1 MB 720 K FD-235F-112 Gray - AT 3. 2/1 MB 1.44 M FD-235HF-101 Black 4. 2/1 MB 1.44 M FD-235HF-117 Gray - AT The TEAC complete kit part numbers are CS-235-00 for numbers 1 and 3 above, and CS-235-03 for numbers 2 and 4 above. I purchased the complete kit with the box and manual part number of TEAC CS-235-03, "5.25 inch Adapter Kit for FD-235 Series Mounting Instructions". The kit came with the following Part Numbers, Names, and Quantities: Part Nos. Parts Name Q'ty 16153616-00 Chassis 5" 1 16788123-03 Front bezel 5", Gray-AT 1 15532119-00 PCBA 5" adapter 1 13189135 Terminal, Faston 187 1 13061957-00 Power Cable Assembly 1 16787587-00 Slide rail A (R) 1 16787587-01 Slide rail B (L) 1 16410305 Screw, 3 x 5 SZMC 9 16499142-00 Screw, UNC 6-32 4 FD-235HF-117 2/1 MB, 3.5 inch drive 1 The chassis is used to secure the 3.5 inch drive and fits into your standard 5.25 inch drive bay. The PCBA adapter plugs into the new drive which has a narrower plug, and adapts it to plug into your standard cable connector. The first thing you do for assembly is attach the front bezel to the chassis, securing it with the supplied 6-32 UNC screws. Next you slide the drive into the chassis and secure it with the supplied 3 x 5 SZMC screws. DO NOT TOUCH THE SPINDLE MOTOR, STEPPING MOTOR OR PRINTED CIRCUIT BOARD. You then attach the slide rails A and B to the sides of the chassis using the UNC 6-32 screws. These rails are only used for assembling the kit for installation in an AT type computer. Now you connect the PCBA 5 inch adapter to the drive's pin header connector. Be sure the adapter plug matches the 2 rows of pins, then secure with 2 3 x 5 SZMC screws. Use 1 3 x 5 SZMC screw to secure the Faston (grounding) terminal to the chassis. Connect the power cable connector to the new drive's power connector, and the kit assembly is complete. The PCBA adapter has the following 3 jumper pins on the top of it: OP ------+---- ------+---- ST ------+---- The middle pin goes "to" host side through the adapter PCBA pin #34. The ST pin runs "from" FD-235 pin #34. When the ST strap is on-state, the output signal from interface pin #34 of FD-235 is connected to the same pin number of the PCBA 5 inch adapter. When the OP strap is on-state, pin #34 of the PCBA 5 inch adapter keeps an open condition. The strap setting at delivery is the ST side shorted. I did not need to change this for my AT type computer. One last step before sliding the drive into your computer is to check the straps (short bars) on the FD-235 drive itself. For the 1.44 Meg drive (FD-235HF-101/117), the jumpers are: + + HH0 +--+ OP + + LHI + + HHI +--+ D1 + + D0 For AT type machines, only OP and D1 must be shorted. This is how is came out of the box, so again, I did not need to change these. If you have the 720 K drive )FD-235F-100/112), the jumpers are: + + MS + + IR + + RY | + + DC +--+ D1 + + D0 Here, for AT type machines, D1 and RY/DC(left) must be shorted. Since I did not test these drives, I cannot say how they come out of the box. That's it, you are now ready to plug and play. Slide the drive into the drive bay of your computer, hook up the power connector adapter, plug in your drive cable to the PCBA 5 inch adapter, ground the Faston terminal and you are ready for testing. Make sure that you plug your drive cable in correctly. Make sure that pin #1 of your cable connector is attached closest to the notch in the PCBA adapter. The first time I plugged my B drive cable into the PCBA adapter, I had it backwards, and when I powered my system up, both my 1.2 Meg A drive and the new 1.44 Meg B drive lights came on and stayed on and I could not access either drive. Once I removed the masking tape which was keeping my A and B drive cables nice and neat, I was able to see the error of my ways and reorient the connector. Then everything worked fine. I replaced my TEAC 360 K B drive with the new TEAC 1.44 Meg drive, and now I was in business. My 1.2 Meg A drive can read and write 360 K and 1.2 Meg 5.25 inch floppy disks, and my new B drive can read and write 720 K and 1.44 Meg 3.5 inch floppy disks. I powered up my system, ran the built-in Setup of my Award 3.03 bios, told setup that my B drive was now a 1.44 Meg drive instead of a 360 K drive, rebooted, and tested my new drive. The first time I inserted a high density 3.5 inch floppy disk and ran format b:, I thought the drive was broke because I didn't hear anything. But the light was on, and my screen showed the familiar format head and cylinder counts changing, so I waited until it said format completed successfully, and then ran NSWP on it and it said 0K in 0 files, 1423K free. Now I was in business. It is the quietest floppy drive I have ever experienced. I next tried a regular 3.5 inch floppy disk like those used by Macintoshes which are not high density, but they are double sided, double density. When I tried to format that disk, I received a format failure, so I looked in my trusty dos manual and saw that to format a 720 K floppy on a 1.44 Meg drive, I had to give the format command some parameters. The correct syntax to use is: format b: /N:9 /T:80 What this does is format the disk to 9 sectors per track, with 80 tracks formatted. You could also specify /V (for adding a volume label) and /S (for copying the operating system files to the floppy disk to create a bootable disk) to the /N and /T parameters if you desire. So there you have it. The TEAC 3.5 inch micro floppy drive I purchased and installed is very quiet, and quite easy to install. I purchased mine at a Silicon Valley computer show/swap for $85 which is very reasonable. The manual is small, 5 x 8 inches, and is only 11 pages, but most likely, its a plug and play situation if you have an AT type computer with Dos 3.3 and the appropriate bios. Have fun. s a plug and play situation if you have an AT type computer with Dos 3.3 and the appropr