HX20 questions

From: PDP11 Hacker ..... <ard_at_siva.bris.ac.uk>
Date: Tue Aug 5 21:08:03 1997

I've just been given an Epson HX20 laptop - it was not working when I got it,
but it didn't take long to kludge over the damaged conductor in the keyboard
flexiprint cable...

Anyway, it came with some rather nice bits :

The microcassette drive and 8 tapes

A TF20 floppy drive unit and cable

A pile of manuals - user manuals for the HX20 and TF20, BASIC reference manual,
and _Technical_ manaul for the HX20. The latter is quite a find, and includes
schematics of the machine, the tape unit and the ROM cartridge.

I am lacking the systems disk for the TF20 - does anyone have one that they
could make a copy of. I can supply a blank disk and pay postage, of course. I
suspect that as I have the machine, I am entitled to have such a disk.

I assume schematics for the TF20 don't exist anywhere...

The TF20 contains a pair of 1/3 height voice-coil drives (like those in the
QX10), and a controller board. The latter contains a Z80, 2K EPROM, 64K DRAM,
the 765 disk controller chip, and TTL glue. There's a daughterboard with the
serial chip on it to communicate with the HX20.

This reminds me of another Epson object I have - a BM5 floppy drive. This looks
like the TF20 (it's a white box, very deep from front to back, with a
vertically mounted drive on the front). However, this drive seems to link to
the internal controller using an ST506-like interface (34 pin and 20 pin
cables), and the controller chips are hard disk controllers. Somebody told me
that it stored 5 Mbytes/disk

Does anyone know anything about this object?

-tony
Received on Tue Aug 05 1997 - 21:08:03 BST