TEAC FD-30A
Today (26. Aug. 2020) I got a nearly new TEAC FD-30A, bought from ebay UK.
What a cute 3" floppy disk drive. Just amazing!

And the best thing is. You can run it with MS/PC-DOS without any problems! Why? The TEAC FD-30A (3") is fully compatible with the TEAC FD-55A (5.25"). Both drives are single sided, but this is no problem with DOS. DOS supports both the single sided 160K (8 sectors/track, FEh) and 180K (9 sectors/track, FCh) logical format.
Another special feature, you can use the hard case 3" floppy on both sides. Just flip it over!
Although the FD-30A can be used in an IBM compatible PC, it was never used there. The FD-30A was used in the Tatung Einstein TC01 for example, see manual below.
Technical specifications

(Source: Brochure TEAC FD-3OA)

(Source: Brochure TEAC FD-3OA)
Pictures


Unlike the brochure of the FD-30 and FD 30A, my drive has only one LSI chip. Basically TEAC always has two LSI chips in its drives (FD-30, FD-55).
- TEAC 7358-01
- 2 x 15 pins, rectangular
- FD-30, U2
- FD-55, U9
- analog
- READ/WRITE CIRCUIT
- read amplifier
- waveform shaper
- write data input latch
- write and erase drivers
- TEAC 1922-00
- 4 x 12 pins, quadratic
- FD-30, U3 (but missing, see pic. 02, red circle)
- FD-55, U6
- digital
- CONTROL CIRCUIT: full logic controll over
- all operations of the drive
- the I/O signals
- the head positioning stepper motor
- the spindle motor
Why my drive has only one LSI chip is unknown to me. It originally comes from a Tatung Einstein TC01. It is possible that special drives were used for these computers. Who knows?


Manuals (M) and brochures (B)
- B: TEAC FD-30 (1983)
- B: TEAC FD-30A (9184)
- M: Tatung Einstein hardware manual