At 19:17 07-05-98 +0100, Tony Duell <ard_at_p850ug1.demon.co.uk> wrote:
>>
>> At 02:34 07-05-98 +0100, ard_at_p850ug1.demon.co.uk (Tony Duell) wrote:
>>
>> >BTW, is a Z-88 (Zenith, not Sinclair for the UK people here) related to
>> >this machine? Is it the cassette version or something?
>>
>> The H-88 (not Z-88) was a converted H-/Z-19 terminal. I never heard of a
>> 'Z'-88. Do you own or have seen a H/Z-89-90-like machine marked Z-88?
>
>I've never seen a Z-88, so I guess it may not have existed. But the H-88
>is very similar to the H-89/Z-90 etc machines...
>
>The Z-89 is also a converted Z-19, at least at the hardware level. Or at
>least there seems to be a Z-19 logic board in there.
Never was a 'Z'-89. The differentiation between Heath/Zenith using the 'H'
or 'Z' in the model name is thus: Only Heath-branded items, whether they
be kit or factory assembled, had an 'H' model number (H-77, H-89, H-19,
H-110, etc,). Zenith-branded items on the other hand had a 'Z' model number
(Z-77, Z-90, Z-19, Z-110, etc.) and were exclusively factory assembled and
sold through third-party retailers or more usually, VARs (Value Added
Retailers). VARs had either exclusive or shared rights to sell ZDS
equipment in a certain geographic region. Heath Company stores handled
Heath-branded items along with, of course, their catalog sales and rarely
ZDS-branded items.
Now notice that there is an 'H'-89 and a 'Z'-90. These were machines that
were mostly the same except for a few changes in the floppy disk hardware,
etc. mentioned previously in this thread. Hence, the usage of the -89 and
-90 numbers to apparently help differentiate between the two systems as far
as available software media is concerned.
Refering to Tony's statement again: ">The Z-89 is also a converted Z-19, at
least at the hardware level. Or at
>least there seems to be a Z-19 logic board in there.", the converted H-19
should have been the H-88 but I'm trying to recall from increasingly fuzzy
memory on that. I will look that up sometime soon as I was quite interested
at one time to get one of the last available conversion kits from Heath to
convert an extra Z-19 terminal I had then (actually, still have) to an
H-89-like machine. Still have the catalog, I think, which shows that kit.
>>
>> Recall I stated that the H-89/Z-90 was built in the same case as the H/Z-19
>> essentially making a single-unit computer with terminal. Kind of handy
>> since the Z-90 machines were often sold to business owners who had
>> small-size offices or whatever. Anyway, Heath Company offered a kit (have
>> to lookup the model number in my old Heath catalog collection -think it was
>> H88-1) consisting of boards, sheet metal, cables, etc. to make a bare-bones
>> H-89, typicaly dubbed H-88. Yes, a cassette interface was available, maybe
>> with this bare-bones thing and/or a stipped down actual H-89.
>
>I _think_ an H-88 is the cassette version. Actually, there were different
>ROMs depending on whether you had cassette or 2 disk controllers (my
>machine couldn't take a cassette interface even if I had one)
I do vaguely recall something about ROM differences between the very early
H-89's and later ones and this cassette thing was the major diff. IIRC.
>
>>
>> The earliest floppy disk system for the 8-bitters was the model H-17 used
>> with the H-8. Used the hard sectored Siemens 5.25" floppy drives (1,2 or 3
>> drives in the case) with an H-17 controller. The H/Z-77 was the
>> soft-sectored 5.25" floppy disk system with 1 or 2 drives and was offered
>> first with the H-89 and Z-90.
>
>I think I've got both of those. I've got a single internal Siemens drive
>linked to a hard sectored controller (only) - a PCB with a USRT and some
>TTL on it. Then I've got a 'double density' controller board using the
>FD 1797 chip linked to the 2 external drives.
>
>> Anyway, the H-8 could use any of these drive systems and the H/Z-89/90 the
>
>Yes, the H-8 is mentioned in my manuals (I have a PAM-8 monitor ROM
>source listing in the HDOS manual, for example..)
Yes, Heath provided virtually *everything*! I think even PAL listings were
provided with the H/Z-100 machines along with its thick monitor ROM
listing. Will have to check my H/Z-100 technical manuals on this too. (Boy,
I'm piling up a bunch of notes of stuff to look up based on this thread.)
Regatds, Chris
-- --
Christian Fandt, Electronic/Electrical Historian
Jamestown, NY USA
Member of Antique Wireless Association
URL:
http://www.ggw.org/freenet/a/awa/
Received on Fri May 08 1998 - 08:13:02 BST