VTech 3.5" floppy drive compatiblity information

[SomeGuy]

A while back I acquired a VTech (Video Technology Computers Ltd) Laser 3.5" floppy disk drive. One would expect that a 3.5" floppy drive for an Apple II clone would work with other Apple II computers, but this is not the case.

The Apple II world of 3.5" drives are a confusing mess of incompatible models and controllers (some combinations of which can go boom!). Various Internet resources were not crystal clear about what this drive is compatible with, so I am posting my findings here.

There are two very good resources that discuss drive and controller compatibility, but they don't discuss clones or integrated controllers.

http://apple2.info/wiki/index.php?title=A2_Floppy_Controllers
http://apple2.info/wiki/index.php?title=3.5_Drive_Compatibility

The Vtech Laser 3.5" floppy drive is a clone of the Macintosh "Apple 800K External" M131, but has a manual eject button.

The Laser 3.5" floppy drive is compatible with:
II+/IIe/IIgs with Vtech UDC card
Laser 128 (later models)/128ex
Macintosh

The Laser 3.5" floppy drive is NOT compatible with:
II+/IIe/IIgs with any other 3.5" cards
IIc/IIc Plus
IIgs
Laser 128 early model (type with slits in the cover, reported may/may not work)

Yes, that's right, this drive is really for the Macintosh, but works with and was sold for the Laser 128/128EX Apple II clone.

The Laser 128 itself supports most Apple 3.5" drives. Its support is equivalent to the Vtech UDC card, a very powerful add-on for the Apple II+/IIe/IIgs.

Reportedly, the Laser 128 SmartPort supports:
Apple IIe/IIc UniDisks (3.5" and 5.25" models)
Macintosh 3.5" drives (the ones without the buttons)
Apple IIGS daisy-chainable 3.5" drives and Apple 5.25" disks
Chinook CT-series 20 MB to 100 MB SmartPort hard drives

(Although according to the resources above, mixing an Apple UniDisk 3.5" and VTech Universal Disk Controller card may go boom. Not the case for the Laser 128?)

The Laser 128 SmartPort can support two 800K 3.5" drives, two 140K 5.25" drives, and one 100 MB CT100 hard drive simultaneously daisy-chained to each other.

 

[njroadfan]

The Laser 3.5" drive lacks the logic found on the daisy chain board on the newer Apple 3.5" Drive that was included with the Apple IIgs, thus will be Macintosh compatible only.

 

[SomeGuy]

Just a little more information, the specific model is LASER FD-356. FCC ID is BNX84H80-2204. The possibly meaningless number "802" is printed on a large sticker.

Both the Laser 128 and UDC manual refer to this Laser floppy drive as the LASER FD-356 3.5" drive. There were apparently two versions, the FD-356 and FD-356DC. The latter would have daisy chain support. The regular one, like this one, has no daisy chain port on the back. Just a plastic break-out cover where the port would be.

The above resources fail to mention that the Apple IIc with the fist (version 255) ROM revision supports NO 3.5" floppy drives at all. This can be rectified by performing a ROM upgrade. But as far as I can tell, this still only supports the one UniDisk 3.5" model (intelligent drive). IIc Plus ROMs can not be used as the IIc Plus has significantly different hardware.

The Laser 128 manual says the Laser 128 computer officially supports:
- LASER FD-100c 5.25" drives or compatibles
- Unidisk 5.25 drives or compatibles
- LASER FD-356 3.5" drives or compatibles
- Unidisk 3.5 drives or compatibles

The Laser 128 tech manual then goes on to describe the two types of 3.5" drives:

The disk drives which are supported by the
computer can be classified into two
categories: intelligent and non-intelligent.
Intelligent disk drives have dedicated
microprocessor and hardware for controlling
the disk read/write operation and it only
receives high-level commands from the host
computer. These include the Unidisk
5.25/3.5 compatible disk drives.
All the other disk drives supported by the
computer are non-intelligent in the sense
that all or most of the disk read/write
operations have to be directly controlled by
the CPU.

Interfacing with non-intelligent 3.5" disk
drives

These refer to LASER FD-356 compatible
3.5" disk drives They are double-side,
double-density drives with a formatted
storage capacity of 800 K-bytes.

Interfacing with intelligent disk drives

Intelligent disk drives include the Unidisk
5.25 and Unidisk 3.5 compatible disk
drives. They have built-in microprocessor,
ROM, RAM and other circuitries for
controlling the disk read/write operations
and are effectively microcomputers on their
own. They only receive and process highlevel
commands (such as read status, format,
read block and write block etc.) from the
host computer.

 

[SomeGuy]

As it turns out these drives have a motorized eject like the Apple Mac drives, even though they have a manual mechanical eject button.

I was testing out Apple II Desktop on this drive, happened to click Eject from the menu, and was quite surprised when the disk popped out all by itself. Not much Apple II software uses that feature, obviously.

The genuine Apple II 3.5" drives I recall seeing before had motorized eject but an electrical eject button so you couldn't eject the disk if the power was off.

 

[VERAULT]

i have that drive. you need the universal floppy controller (i have the ftanklin version) to use that drive.

 

[SomeGuy]

I finally got up the nerve to open the case. As I suspected, it has three plastic latches on each side. So, after I removed the four screws that hold the drive assembly in place, and the two case screws underneath the back feet, I had to wiggle the top back and forth to the back with some effort.

Surprisingly none of them broke.

The drive assembly inside this one is a Chinon F-354 MC Rev b with a custom PCB.



Posted in that info in 2018? Darn everything takes too long.

 

[VERAULT]

dont feel bad. i have soms posts i havent finished i openes up years ago as well .as long as you intend to get back to them
.