[sebhc] H89s

[Lee Hart]

Pi3cubed at aol.com wrote:
> I have, I believe, four H89 computers. The nameplate on one of
> them states this, but the three others have a nameplate that just
> says "Heathkit Computer".

The exact designations are a little confused. Technically,

H means it was sold by Heath as a kit
Z means it was sold by Zenith (assembled)
WH means it was sold by Heath not as a kit, but assembled

19 is the terminal only
88 is the computer with no disk drives (cassette storage)
89 is the computer with a hard-sector (H17 format) floppy controller
90 is the computer with a soft-sector (H37 format) floppy controller

So an "H19" is a Heath kit terminal; a "WH89" is a Heath assembled
computer with H17 controller; a "Z90" is a Zenith assembled computer
with H37 controller. However, the various models were constantly being
modified and upgraded by both the factory and the end-users; so what it
says on the outside frequently does not reflect what hardware has been
installed inside.

There were two types of front-panel nameplates. The early style was
orange, yellow, and blue background with "Heathkit" and the model number
"H19", "H88", or "H89" printed on it in black letters. The later style
was black, and said only "Zenith Data Systems" or "Heathkit Computer".

> I believe the floppy drives use hard-sectored disks.

You can confirm this by looking at the disk controller board in the
right-most slot on the CPU board. If it is mostly empty, it is a
hard-sector board. If it is very full of parts and has a dangling
rainbow-colored cable running down to the CPU board, it is the
soft-sector board.
-- 
"Never doubt that a small group of committed people can change the
world. Indeed, it's the only thing that ever has!" -- Margaret Meade
--
Lee A. Hart  814 8th Ave N  Sartell MN 56377  leeahart_at_earthlink.net

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