21 Jul
2012
21 Jul
'12
2:21 p.m.
It looks like I'm back in business collecting vintage computers. I went to the town
dump today and found what looks like an H89 but the model number tag on the back says
NN89-29. I haven't tried opening it up to see what's inside yet but it has a
floppy drive so I assume it isn't just a H19 terminal. Also, on the front it says
"Heathkit Computer". Even though I've had vintage computers before I've
never followed good procedures when trying to bring them up. Usually, I just plug in the
power cord and hope for the best. I'd like to do a little better this time. Can anyone
suggest an approach to bringing this beast to life that minimizes the chances that
I'll fry it the first time I power it on?
Thanks,
David
21 Jul
21 Jul
2:40 p.m.
One method I've heard involves powering up slowly with a variac.
Sent from my iPad
On 2012-07-21, at 5:21 PM, David Betz <dbetz at xlisper.com> wrote:
It looks like I'm back in business collecting
vintage computers. I went to the town dump today and found what looks like an H89 but the
model number tag on the back says NN89-29. I haven't tried opening it up to see
what's inside yet but it has a floppy drive so I assume it isn't just a H19
terminal. Also, on the front it says "Heathkit Computer". Even though I've
had vintage computers before I've never followed good procedures when trying to bring
them up. Usually, I just plug in the power cord and hope for the best. I'd like to do
a little better this time. Can anyone suggest an approach to bringing this beast to life
that minimizes the chances that I'll fry it the first time I power it on?
Thanks,
David
2:45 p.m.
With the power supply disconnected from the computer, I hope
---
Enviado do meu Motorola PT550
Meu site: http://www.tabalabs.com.br
----- Original Message -----
From: "Paul Anderson" <wackyvorlon at me.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Saturday, July 21, 2012 6:40 PM
Subject: Re: Heathkit H89 maybe?
One method I've heard involves powering up slowly
with a variac.
Sent from my iPad
On 2012-07-21, at 5:21 PM, David Betz <dbetz at xlisper.com> wrote:
> It looks like I'm back in business collecting vintage computers. I went
> to the town dump today and found what looks like an H89 but the model
> number tag on the back says NN89-29. I haven't tried opening it up to see
> what's inside yet but it has a floppy drive so I assume it isn't just a
> H19 terminal. Also, on the front it says "Heathkit Computer". Even though
> I've had vintage computers before I've never followed good procedures
> when trying to bring them up. Usually, I just plug in the power cord and
> hope for the best. I'd like to do a little better this time. Can anyone
> suggest an approach to bringing this beast to life that minimizes the
> chances that I'll fry it the first time I power it on?
>
> Thanks,
> David
22 Jul
22 Jul
11:39 a.m.
With the power supply disconnected from the computer, I hope
Actually, with a linear PSU you nmight get away without having to
disconenct the PSU. Put a votlmeter on each of the main outputs, and
slowly crank up the mains input on the Variac. Stop aif any of the
outputs shows signs of going too high.
I think the H89/Z90 PSU would behave reasoably like that.
-tony
21 Jul
21 Jul
9:51 p.m.
From: dbetz at xlisper.com
It looks like I'm back in business collecting vintage computers. I went to the town
dump today and found what looks like an H89 but the model number tag on the back says
NN89-29. I haven't tried opening it up to see what's inside yet but it has a
floppy drive so I assume it isn't just a H19 terminal. Also, on the front it says
"Heathkit Computer". Even though I've had vintage computers before I've
never followed good procedures when trying to bring them up. Usually, I just plug in the
power cord and hope for the best. I'd like to do a little better this time. Can anyone
suggest an approach to bringing this beast to life that minimizes the chances that
I'll fry it the first time I power it on?
Thanks,
David
Hi David
We have a mail group that
is an active group that specializes in H8/H89s. It is a Googles group SEBHC.
One of the group members has our disk archives. Depnding on the format you need,
we have several different achive formats.
If you have hard sectored, determined by having a H27 controller ( might be
the wrong number ), I wrote a boot strap a number of years ago that can
get you started. It works through the serial ports and the PC end uses a DOS
program. One of the other fellows wrote a windows program for the PC
end.
The soft sectored card has a uP on it. One can create disk if you mount a
360K disk drive in your PC.
You can try to bring it up slow but I suggest disconnecting the video board.
It may still pop a tantalum or two. I recommend removing the cover so you
can spot the source of the smoke before shutting the power.
Also watch out for the unfused and unswitched line filter, that has been known
to blow ( don't leave it plugged in when not around ).
If you have a hard sectored disk, you'll need 10 sectored disk. I had a number
of manual punches made but sold out ( I still have a couple of the 16 sectored
punches if anyone else want one ).
One can still buy new disk at about $5 each. I use old 360K and my punch
to make what I need.
Diwght
10:19 p.m.
Hi Dwight,
Thanks for your suggestions.
I just opened up my H89 and there are a bunch of modules plugged into a backplane. The
backplane itself is labeled "mako data products MH89 plus 3". I guess it's a
third party module. Plugged into it were the following modules:
DISK I/O 85-2601-1
DOUBLE DENSITY 85-2597-1
SERIAL/PARALLEL I/O BOARD
N.O.G.D.S HA-89-3-B
ATRA H-101-A with a H-201-B daughterboard
The last two seem like they have something to do with sound generation and the N.O.G.D.S.
board also has a video chip on it.
Beyond that, there are six toggle switches mounted between the main keyboard and the
numeric keypad and another toggle switch mounted on the floppy drive along with a second
LED.
Do you have any idea what any of this stuff is? In particular, do you know if the two disk
controller boards are for hard or soft sectored drives?
Thanks,
David
On Jul 22, 2012, at 12:51 AM, dwight elvey wrote:
From: dbetz at xlisper.com
It looks like I'm back in business collecting vintage computers. I went to the town
dump today and found what looks like an H89 but the model number tag on the back says
NN89-29. I haven't tried opening it up to see what's inside yet but it has a
floppy drive so I assume it isn't just a H19 terminal. Also, on the front it says
"Heathkit Computer". Even though I've had vintage computers before I've
never followed good procedures when trying to bring them up. Usually, I just plug in the
power cord and hope for the best. I'd like to do a little better this time. Can anyone
suggest an approach to bringing this beast to life that minimizes the chances that
I'll fry it the first time I power it on?
Thanks,
David
Hi David
We have a mail group that
is an active group that specializes in H8/H89s. It is a Googles group SEBHC.
One of the group members has our disk archives. Depnding on the format you need,
we have several different achive formats.
If you have hard sectored, determined by having a H27 controller ( might be
the wrong number ), I wrote a boot strap a number of years ago that can
get you started. It works through the serial ports and the PC end uses a DOS
program. One of the other fellows wrote a windows program for the PC
end.
The soft sectored card has a uP on it. One can create disk if you mount a
360K disk drive in your PC.
You can try to bring it up slow but I suggest disconnecting the video board.
It may still pop a tantalum or two. I recommend removing the cover so you
can spot the source of the smoke before shutting the power.
Also watch out for the unfused and unswitched line filter, that has been known
to blow ( don't leave it plugged in when not around ).
If you have a hard sectored disk, you'll need 10 sectored disk. I had a number
of manual punches made but sold out ( I still have a couple of the 16 sectored
punches if anyone else want one ).
One can still buy new disk at about $5 each. I use old 360K and my punch
to make what I need.
Diwght
10:49 p.m.
Hi Dwight,
Thanks for your suggestions.
I just opened up my H89 and there are a bunch of modules plugged into a backplane. The
backplane itself is labeled "mako data products MH89 plus 3". I guess it's a
third party module. Plugged into it were the following modules:
DISK I/O 85-2601-1
DOUBLE DENSITY 85-2597-1
This is a soft sectored board. I think the other is hard sectored. It sounds like
it was setup to use either. I'd have to check as my machines are in storeage
right now.
It sounds like an unusual machine.
Dwight
SERIAL/PARALLEL I/O BOARD
N.O.G.D.S HA-89-3-B
ATRA H-101-A with a H-201-B daughterboard
The last two seem like they have something to do with sound generation and the N.O.G.D.S.
board also has a video chip on it.
Beyond that, there are six toggle switches mounted between the main keyboard and the
numeric keypad and another toggle switch mounted on the floppy drive along with a second
LED.
Do you have any idea what any of this stuff is? In particular, do you know if the two
disk controller boards are for hard or soft sectored drives?
Thanks,
David
On Jul 22, 2012, at 12:51 AM, dwight elvey wrote:
From: dbetz at xlisper.com
It looks like I'm back in business collecting vintage computers. I went to the town
dump today and found what looks like an H89 but the model number tag on the back says
NN89-29. I haven't tried opening it up to see what's inside yet but it has a
floppy drive so I assume it isn't just a H19 terminal. Also, on the front it says
"Heathkit Computer". Even though I've had vintage computers before I've
never followed good procedures when trying to bring them up. Usually, I just plug in the
power cord and hope for the best. I'd like to do a little better this time. Can anyone
suggest an approach to bringing this beast to life that minimizes the chances that
I'll fry it the first time I power it on?
Thanks,
David
Hi David
We have a mail group that
is an active group that specializes in H8/H89s. It is a Googles group SEBHC.
One of the group members has our disk archives. Depnding on the format you need,
we have several different achive formats.
If you have hard sectored, determined by having a H27 controller ( might be
the wrong number ), I wrote a boot strap a number of years ago that can
get you started. It works through the serial ports and the PC end uses a DOS
program. One of the other fellows wrote a windows program for the PC
end.
The soft sectored card has a uP on it. One can create disk if you mount a
360K disk drive in your PC.
You can try to bring it up slow but I suggest disconnecting the video board.
It may still pop a tantalum or two. I recommend removing the cover so you
can spot the source of the smoke before shutting the power.
Also watch out for the unfused and unswitched line filter, that has been known
to blow ( don't leave it plugged in when not around ).
If you have a hard sectored disk, you'll need 10 sectored disk. I had a number
of manual punches made but sold out ( I still have a couple of the 16 sectored
punches if anyone else want one ).
One can still buy new disk at about $5 each. I use old 360K and my punch
to make what I need.
Diwght
22 Jul
22 Jul
11:47 a.m.
Hi Dwight,
Thanks for your suggestions.
I just opened up my H89 and there are a bunch of modules plugged into
a backplane. The backplane itself is labeled "mako data products MH89
plus 3". I guess it's a third party module. Plugged into it were the
following modules:
That does not sound like a 'stock' H89. The original layout was somethign
like :
At hte back are 2 large-ish PCBs. The rearmost one is the H19/Z19
terminal (Z80 baseed). In front of it is another Z80 processor board that
runs the user software (CPM, etc). There are 6 (IIRC) connectors o nthis
board for add-ones, 3 each side of the CRT neck. They are not all the
same by any means. One of the ones on the left is normally ued for an
eaxta 16K RAM card (which is bank-switched with the boot ROM, etc). The
ones on the right normally hold a triple RS222 port card and 1 or 2
floppy controllers.
DISK I/O 85-2601-1
DOUBLE DENSITY 85-2597-1
SERIAL/PARALLEL I/O BOARD
N.O.G.D.S HA-89-3-B
ATRA H-101-A with a H-201-B daughterboard
The last two seem like they have something to do with sound generation
and the N.O.G.D.S. board also has a video chip on it.
WHich video chip?
Wheee is the processor in all this? Do you have the H89 docuemntation? If
so, is there any similarly between your machine and the docs?
Beyond that, there are six toggle switches mounted between the main
keyboard and the numeric keypad and another toggle switch mounted on the
floppy drive along with a second LED.
Cerainly non-standerd. Whare are the switches and LED connected to?
Do you have any idea what any of this stuff is? In particular, do you
know if the two disk controller boards are for hard or soft sectored
drives?
The drive are the same, there's no index/sector pulse seapration don in
5.25" drives.
IRIC, the oriignal Heathkit controlelr was for hard sectored disks, and
used a synchronous serial chip and soem glue logic. Nothing that screams
'floppy controller'. The double-desnity card ad a Western Digital
(WD179x?) chip on it, and used soft-sectoroed disks.
I'd look at the cards you have, see if you vna identify any of the ICs.
-tony
5:21 p.m.
On Jul 22, 2012, at 2:47 PM, Tony Duell wrote:
This one seems to have a third party backplane that will accept six boards on the right
side. There is also a module plugged into one of the slots on the left side that looks
like extended memory.
TMS9918
I don't see any way to discover what they're connected to without doing a major
disassembly.
I've tried to disassemble as little as possible so far. The disk controllers I believe
are standard Heathkit ones. I've looked up the board numbers and they seem to
correspond to the hard-sectored controller and the double density soft-sectored
controller. The double density board has a floppy controller chip on it.
Hi Dwight,
Thanks for your suggestions.
I just opened up my H89 and there are a bunch of modules plugged into
a backplane. The backplane itself is labeled "mako data products MH89
plus 3". I guess it's a third party module. Plugged into it were the
following modules:
That does not sound like a 'stock' H89. The original layout was somethign
like :
At hte back are 2 large-ish PCBs. The rearmost one is the H19/Z19
terminal (Z80 baseed). In front of it is another Z80 processor board that
runs the user software (CPM, etc). There are 6 (IIRC) connectors o nthis
board for add-ones, 3 each side of the CRT neck. They are not all the
same by any means. One of the ones on the left is normally ued for an
eaxta 16K RAM card (which is bank-switched with the boot ROM, etc). The
ones on the right normally hold a triple RS222 port card and 1 or 2
floppy controllers.
DISK I/O 85-2601-1
DOUBLE DENSITY 85-2597-1
SERIAL/PARALLEL I/O BOARD
N.O.G.D.S HA-89-3-B
ATRA H-101-A with a H-201-B daughterboard
The last two seem like they have something to do with sound generation
and the N.O.G.D.S. board also has a video chip on it.
WHich video chip?
Wheee is the processor in all this? Do you have the H89 docuemntation? If
so, is there any similarly between your machine and the docs?
Sorry, I failed to mention that the normal CPU and terminal boards are behind the CRT at
the back of the case.
Beyond that, there are six toggle switches mounted between the main
keyboard and the numeric keypad and another toggle switch mounted on the
floppy drive along with a second LED.
Cerainly non-standerd. Whare are the switches and LED connected to?
Do you have any idea what any of this stuff is? In particular, do you
know if the two disk controller boards are for hard or soft sectored
drives?
The drive are the same, there's no index/sector pulse seapration don in
5.25" drives.
IRIC, the oriignal Heathkit controlelr was for hard sectored disks, and
used a synchronous serial chip and soem glue logic. Nothing that screams
'floppy controller'. The double-desnity card ad a Western Digital
(WD179x?) chip on it, and used soft-sectoroed disks.
I'd look at the cards you have, see if you vna identify any of the ICs. -tony
23 Jul
23 Jul
12:20 p.m.
At the back
are 2 large-ish PCBs. The rearmost one is the H19/Z19
terminal (Z80 baseed). In front of it is another Z80 processor board that
runs the user software (CPM, etc). There are 6 (IIRC) connectors o nthis
board for add-ones, 3 each side of the CRT neck. They are not all the
same by any means. One of the ones on the left is normally ued for an
eaxta 16K RAM card (which is bank-switched with the boot ROM, etc). The
ones on the right normally hold a triple RS222 port card and 1 or 2
floppy controllers.
This one seems to have a third party backplane that will accept six boards on the right side. There is also a module
plugged into one of
the slots on the left side that looks like extended memory.
[...]
N.O.G.D.S HA-89-3-B
ATRA H-101-A with a H-201-B daughterboard
The last two seem like they have something to do with sound generation
and the N.O.G.D.S. board also has a video chip on it.
WHich video chip? Beyond that, there are six toggle switches mounted
between the main
keyboard and the numeric keypad and another toggle switch mounted on the
floppy drive along with a second LED.
Cerainly non-standerd. Whare are the switches and LED connected to? I've tried to disassemble as little as possible so
far. The disk
It's looks tight, but remember it was assmeble,d and even designed ot be
assembled by a hobbyist. So it is possible to work on.
controllers I believe are standard Heathkit ones.
I've looked up the
board numbers and they seem to correspond to the hard-sectored
controller and the double density soft-sectored controller. The double
density board has a floppy controller chip on it.
That sounds right. Having the 2 controllers is not uncommon.
-tony
22 Jul
22 Jul
11:37 a.m.
It looks like I'm back in business collecting vintage computers. I
went to the town dump today and found what looks like an H89 but the
model number tag on the back says NN89-29. I haven't tried opening it up
to see what's inside yet but it has a floppy drive so I assume it isn't
just a H19 terminal. Also, on the front it says "Heathkit Computer".
If it is an H89/Z90, then it will be quite tightly packed inside and not
easy to work on. From memroy, the floppy drive comes out easily, and
it's best to that that out early on to have better acess to the other bits.
Even though I've had vintage computers before
I've never followed good
procedures when trying to bring them up. Usually, I just plug in the
power cord and hope for the best. I'd like to do a little better this
time. Can anyone suggest an approach to bringing this beast to life that
minimizes the chances that I'll fry it the first time I power it on?
The PSU is linear, and mostly jsut behind the floppy drive. But something
is tellign me that there are voltage regulators on at least one of the
logic boards (the H19 terminal board?) so it's not totally trivial to
test the PSU on dummy load. Iseem to rememer when I brought my Z90 to
life, I started by temporarily tuning it into an Z19 terminal and gettign
that to work first.
I certainyl did test the bare PSU on its own, that may include the
regualtors for the comptuer section. I also seem to rememebr that many,
if not all, of the ICs on the terminal board were socketed, so I pulled
those, at least the hard-to-find or expensive ones, and powered up at
litte as I could co check votlages.
-tony
12:26 p.m.
I certainyl did test the bare PSU on its own, that may
include the
regualtors for the comptuer section. I also seem to rememebr that many,
if not all, of the ICs on the terminal board were socketed, so I pulled
those, at least the hard-to-find or expensive ones, and powered up at
litte as I could co check votlages.
I'm afraid I broke my own rule again and just plugged in the H89 to see what would
happen. Fortunately, nothing dramatic happened. The display came up with the text rolling
but it stabilized as it warmed up. I ended up with an incrementing clock in the lower
right corner and a cursor in the upper left. If I put it in local mode I can type on the
keyboard and see the correct characters appear on the monitor so the terminal board seems
to work. I don't have a boot floppy so I can't get much further.
4535
days inactive
4537
days old
11 comments
5 participants
participants (5)
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