Re: Flex Disc options for the HP 9825

[Curious Marc]

Same here, count me in for extra PCBs.

Marc

 

From: cctech <cctech-boun...@classiccmp.org> on behalf of Craig Ruff 
<cr...@ruffspot.net>
Reply-To: "cct...@classiccmp.org" <cct...@classiccmp.org>
Date: Saturday, December 10, 2016 at 10:24 AM
To: "cct...@classiccmp.org" <cct...@classiccmp.org>
Subject: Re: Flex Disc options for the HP 9825

 

Excellent news!  I eagerly look forward to this so I can get my 9825T talking 
to my 9895A!  If you spin a PC board, I will be willing to purchase one or two 
if you end up with extras or are willing to coordinate an order.

RE: Flex Disc options for the HP 9825

[Rik Bos]

> -Oorspronkelijk bericht-
> Van: cctech [mailto:cctech-boun...@classiccmp.org] Namens Paul Berger
> Verzonden: zaterdag 10 december 2016 1:37
> Aan: General Discussion: On-Topic and Off-Topic Posts
> Onderwerp: Re: Flex Disc options for the HP 9825
> 
> Some time ago there was a discussion about the elusive 98228A ROM that
> supports both the 9885 and 9895 diskette drive units on a 9825T, well good
> news!  A fellow MoHPC member David Ramsey very kindly loaned me his, and
> with a little careful reading of the service manual along with studying
Tony
> Duell's schematic I got a good idea of how it work, and observing the
memory
> bus using a logic analyzer confirmed how it worked.  I was able to dump
the
> ROM using GPIO cards in a 9920 to simulate the memory bus, I actually went
on
> and dumped all the ROMs in the 9825T as well as a couple other I had.  I
have
> successfully created a clone of the ROM and have even fit it into a a ROM
shell.
> I am going to try creating a PCB for it too, what I have now is just hand
wired,
> but it works.  In the end the ROM module did not turn out to be very
> complicated.  I am just in the process of documenting my project and will
> release a package soon with full documentation and most importantly the
ROM
> image.  I plan to donate my package along with all of my ROM images to
> hpmuseum.net.
> 
> Paul.

Great work Paul.

-Rik

Re: Flex Disc options for the HP 9825

[Craig Ruff]

Excellent news!  I eagerly look forward to this so I can get my 9825T talking 
to my 9895A!  If you spin a PC board, I will be willing to purchase one or two 
if you end up with extras or are willing to coordinate an order.

Re: Flex Disc options for the HP 9825

[Curious Marc]

Fantastic! Can't wait for the info.
Marc

> On Dec 9, 2016, at 4:36 PM, Paul Berger  wrote:
> 
> Some time ago there was a discussion about the elusive 98228A ROM that 
> supports both the 9885 and 9895 diskette drive units on a 9825T, well good 
> news!  A fellow MoHPC member David Ramsey very kindly loaned me his, and with 
> a little careful reading of the service manual along with studying Tony 
> Duell's schematic I got a good idea of how it work, and observing the memory 
> bus using a logic analyzer confirmed how it worked.  I was able to dump the 
> ROM using GPIO cards in a 9920 to simulate the memory bus, I actually went on 
> and dumped all the ROMs in the 9825T as well as a couple other I had.  I have 
> successfully created a clone of the ROM and have even fit it into a a ROM 
> shell.  I am going to try creating a PCB for it too, what I have now is just 
> hand wired, but it works.  In the end the ROM module did not turn out to be 
> very complicated.  I am just in the process of documenting my project and 
> will release a package soon with full documentation and most importantly the 
> ROM image.  I plan to donate my package along with all of my ROM images to 
> hpmuseum.net.
> 
> Paul.

Re: Flex Disc options for the HP 9825

[Paul Berger]

Some time ago there was a discussion about the elusive 98228A ROM that 
supports both the 9885 and 9895 diskette drive units on a 9825T, well 
good news!  A fellow MoHPC member David Ramsey very kindly loaned me 
his, and with a little careful reading of the service manual along with 
studying Tony Duell's schematic I got a good idea of how it work, and 
observing the memory bus using a logic analyzer confirmed how it 
worked.  I was able to dump the ROM using GPIO cards in a 9920 to 
simulate the memory bus, I actually went on and dumped all the ROMs in 
the 9825T as well as a couple other I had.  I have successfully created 
a clone of the ROM and have even fit it into a a ROM shell.  I am going 
to try creating a PCB for it too, what I have now is just hand wired, 
but it works.  In the end the ROM module did not turn out to be very 
complicated.  I am just in the process of documenting my project and 
will release a package soon with full documentation and most importantly 
the ROM image.  I plan to donate my package along with all of my ROM 
images to hpmuseum.net.


Paul.

Re: Flex Disc options for the HP 9825

[curiousmarc3]

Thanks. That's a very clean mod!
Marc

> On Aug 15, 2016, at 7:35 AM, Rik Bos <hp-...@xs4all.nl> wrote:
> 
> 
> https://flic.kr/p/L8SNPJ
> 
> Done.
> 
> -Rik
> 
>> -Oorspronkelijk bericht-
>> Van: cctech [mailto:cctech-boun...@classiccmp.org] Namens Curious Marc
>> Verzonden: zondag 14 augustus 2016 21:08
>> Aan: General Discussion: On-Topic Posts
>> Onderwerp: Re: Flex Disc options for the HP 9825
>> 
>> Would you pictures of it and where it sits in the machine by any chance?
>> Marc
>> 
>> Sent from my iPad
>> 
>>> On Aug 14, 2016, at 10:22 AM, Rik Bos <hp-...@xs4all.nl> wrote:
>>> 
>>> Paul,
>>> 
>>> It is a small extra pcb( with hp logo). Both my machines are build in 
>>> Germany,
>> which is logic because I’m living in the Netherlands and aquired both in 
>> Europe.
>>> So it could be a local modification made by the Boeblingen factory or even 
>>> HP
>> Netherlands.
>>> I’m happy with it
>>> 
>>> -Rik
>>> 
>>> Van: Paul Berger
> 

Re: Flex Disc options for the HP 9825

[Ian S. King]

On Mon, Aug 15, 2016 at 9:25 AM, Rik Bos  wrote:

> No, they just blow the main fuse.
> The thyristor is a 2N4441.
>
> -Rik
>
> Van: Paul Berger


In my experience, 'blow the main fuse' is the usual approach with a crowbar
- in other words, trigger the protection device that already exists.

-- 
Ian S. King, MSIS, MSCS, Ph.D. Candidate
The Information School 
Dissertation: "Why the Conversation Mattered: Constructing a Sociotechnical
Narrative Through a Design Lens

Archivist, Voices From the Rwanda Tribunal 
Value Sensitive Design Research Lab 

University of Washington

There is an old Vulcan saying: "Only Nixon could go to China."

RE: Flex Disc options for the HP 9825

[Rik Bos]

No, they just blow the main fuse.
The thyristor is a 2N4441.

-Rik

Van: Paul Berger

Re: Flex Disc options for the HP 9825

[Paul Berger]

Wow that is a nicely done add-on,  It looks like it monitors +5 and +12 
and crowbars the RAW +20.   Did they insert any fuses? or do they rely 
on that blowing the main fuse?  That should be easy to duplicate even on 
a breadboard


Paul

On 2016-08-15 11:35 AM, Rik Bos wrote:

https://flic.kr/p/L8SNPJ

Done.

-Rik


-Oorspronkelijk bericht-
Van: cctech [mailto:cctech-boun...@classiccmp.org] Namens Curious Marc
Verzonden: zondag 14 augustus 2016 21:08
Aan: General Discussion: On-Topic Posts
Onderwerp: Re: Flex Disc options for the HP 9825

Would you pictures of it and where it sits in the machine by any chance?
Marc

Sent from my iPad


On Aug 14, 2016, at 10:22 AM, Rik Bos <hp-...@xs4all.nl> wrote:

Paul,

It is a small extra pcb( with hp logo). Both my machines are build in Germany,

which is logic because I’m living in the Netherlands and aquired both in Europe.

So it could be a local modification made by the Boeblingen factory or even HP

Netherlands.

I’m happy with it

-Rik

Van: Paul Berger

RE: Flex Disc options for the HP 9825

[Rik Bos]

https://flic.kr/p/L8SNPJ

Done.

-Rik

> -Oorspronkelijk bericht-
> Van: cctech [mailto:cctech-boun...@classiccmp.org] Namens Curious Marc
> Verzonden: zondag 14 augustus 2016 21:08
> Aan: General Discussion: On-Topic Posts
> Onderwerp: Re: Flex Disc options for the HP 9825
> 
> Would you pictures of it and where it sits in the machine by any chance?
> Marc
> 
> Sent from my iPad
> 
> > On Aug 14, 2016, at 10:22 AM, Rik Bos <hp-...@xs4all.nl> wrote:
> >
> > Paul,
> >
> > It is a small extra pcb( with hp logo). Both my machines are build in 
> > Germany,
> which is logic because I’m living in the Netherlands and aquired both in 
> Europe.
> > So it could be a local modification made by the Boeblingen factory or even 
> > HP
> Netherlands.
> > I’m happy with it
> >
> > -Rik
> >
> > Van: Paul Berger

RE: Flex Disc options for the HP 9825

[Rik Bos]

Paul,

It is a small extra pcb( with hp logo). Both my machines are build in Germany, 
which is logic because I’m living in the Netherlands and aquired both in Europe.
So it could be a local modification made by the Boeblingen factory or even HP 
Netherlands.
I’m happy with it

-Rik

Van: Paul Berger

Re: Flex Disc options for the HP 9825

[Curious Marc]

Would you pictures of it and where it sits in the machine by any chance?
Marc

Sent from my iPad

> On Aug 14, 2016, at 10:22 AM, Rik Bos  wrote:
> 
> Paul,
> 
> It is a small extra pcb( with hp logo). Both my machines are build in 
> Germany, which is logic because I’m living in the Netherlands and aquired 
> both in Europe.
> So it could be a local modification made by the Boeblingen factory or even HP 
> Netherlands.
> I’m happy with it
> 
> -Rik
> 
> Van: Paul Berger

Re: Flex Disc options for the HP 9825

[curiousmarc3]

Thanks!
Marc

> On Aug 13, 2016, at 1:19 PM, Rik Bos <hp-...@xs4all.nl> wrote:
> 
> Marc,
> 
> Building a crowbar is easy, just take a Zener a little higher than the psu
> voltage eg 5.2V for 5V rail put a resistor of 1k in series take a Thyristor
> big enough to take about 150% of the schort current and connect it to the
> zener through a small resistor. I suppose you can do the math  ;) 
> Be sure to put a crowbar on both the +12V and +5V and you could consider one
> on the -12V rail but that voltage doesn't have a pass transistor but a 320K
> voltage regulator which has a reasonable protection for over voltage.
> The -5V is connected to the -12V through a zener.
> Tony reverse engineered the schematics, you can download them a the HP
> Museum website or become a member of the HPCC and order the CD with all
> Tony's diagrams (a lot of eexcellent work).
> 
> -Rik
> 
>> -Oorspronkelijk bericht-
>> Van: cctech [mailto:cctech-boun...@classiccmp.org] Namens
>> curiousma...@gmail.com
>> Verzonden: zaterdag 13 augustus 2016 12:15
>> Aan: General Discussion: On-Topic Posts
>> Onderwerp: Re: Flex Disc options for the HP 9825
>> 
>> Thanks for the info. Any schematics of the modification?
>> Marc
>> 
>> 
>>> On Aug 13, 2016, at 2:37 AM, Rik Bos <hp-...@xs4all.nl> wrote:
>>> 
>>> 
>>> For what it's worth a small warning about the HP 9825 series computers.
>>> The power supply doesn't have a crowbar(over voltage protection), so a
>>> transistor failure in the Psu can be catastrophic.
>>> On the other hand the two 9835's I have, which uses the same form
>>> factor and almost the same power supply layout are HP modified with
>> crowbars added.
>>> It seems to be good practice to add some ov-protection to the HP 9825
>>> supply because the switching transistor and 723 voltage regulators
>>> don't have the eternal life.
>>> And there no certain prediction in how they fail, short or open
>>> circuit, I found out the hard way several years ago.
>>> 
>>> -Rik
> 

Re: Flex Disc options for the HP 9825

[Paul Berger]

I wonder if the crowbars might have been a later revision of of the 
power supply.  After the accident with my 9835A I had to completely 
rebuild the +12V regulator both the 723 and the pass transistor as well 
as a few passive components.  I did not see any evidence of crowbars, 
and  the power supply in my 9835A seems to match the diagram in the 9835 
service guide.  If I was to add crowbars to this power supply I would be 
temped to monitor the voltages and crowbar the raw DC when an 
overvoltage is detected, in my case it was the -20V raw that did all of 
the damage.


Paul.

On 2016-08-13 6:37 AM, Rik Bos wrote:

For what it's worth a small warning about the HP 9825 series computers.
The power supply doesn't have a crowbar(over voltage protection), so a
transistor failure in the Psu can be catastrophic.
On the other hand the two 9835's I have, which uses the same form factor and
almost the same power supply layout are HP modified with crowbars added.
It seems to be good practice to add some ov-protection to the HP 9825 supply
because the switching transistor and 723 voltage regulators don't have the
eternal life.
And there no certain prediction in how they fail, short or open circuit, I
found out the hard way several years ago.

-Rik

RE: Flex Disc options for the HP 9825

[Rik Bos]

Marc,

Building a crowbar is easy, just take a Zener a little higher than the psu
voltage eg 5.2V for 5V rail put a resistor of 1k in series take a Thyristor
big enough to take about 150% of the schort current and connect it to the
zener through a small resistor. I suppose you can do the math  ;) 
Be sure to put a crowbar on both the +12V and +5V and you could consider one
on the -12V rail but that voltage doesn't have a pass transistor but a 320K
voltage regulator which has a reasonable protection for over voltage.
The -5V is connected to the -12V through a zener.
Tony reverse engineered the schematics, you can download them a the HP
Museum website or become a member of the HPCC and order the CD with all
Tony's diagrams (a lot of eexcellent work).

-Rik

> -Oorspronkelijk bericht-
> Van: cctech [mailto:cctech-boun...@classiccmp.org] Namens
> curiousma...@gmail.com
> Verzonden: zaterdag 13 augustus 2016 12:15
> Aan: General Discussion: On-Topic Posts
> Onderwerp: Re: Flex Disc options for the HP 9825
> 
> Thanks for the info. Any schematics of the modification?
> Marc
> 
> 
> > On Aug 13, 2016, at 2:37 AM, Rik Bos <hp-...@xs4all.nl> wrote:
> >
> >
> > For what it's worth a small warning about the HP 9825 series computers.
> > The power supply doesn't have a crowbar(over voltage protection), so a
> > transistor failure in the Psu can be catastrophic.
> > On the other hand the two 9835's I have, which uses the same form
> > factor and almost the same power supply layout are HP modified with
> crowbars added.
> > It seems to be good practice to add some ov-protection to the HP 9825
> > supply because the switching transistor and 723 voltage regulators
> > don't have the eternal life.
> > And there no certain prediction in how they fail, short or open
> > circuit, I found out the hard way several years ago.
> >
> > -Rik
> >

Re: Flex Disc options for the HP 9825

[Jos Dreesen]

On 13.08.2016 11:37, Rik Bos wrote:


For what it's worth a small warning about the HP 9825 series computers.
The power supply doesn't have a crowbar(over voltage protection), so a
transistor failure in the Psu can be catastrophic.
On the other hand the two 9835's I have, which uses the same form factor and
almost the same power supply layout are HP modified with crowbars added.
It seems to be good practice to add some ov-protection to the HP 9825 supply
because the switching transistor and 723 voltage regulators don't have the
eternal life.
And there no certain prediction in how they fail, short or open circuit, I
found out the hard way several years ago.

-Rik



The same is true of the PDP8/L. I also found out the hard way
That L is still not running, but the PS now has a crowbar !


Jos

RE: Flex Disc options for the HP 9825

[Rik Bos]

For what it's worth a small warning about the HP 9825 series computers.
The power supply doesn't have a crowbar(over voltage protection), so a
transistor failure in the Psu can be catastrophic.
On the other hand the two 9835's I have, which uses the same form factor and
almost the same power supply layout are HP modified with crowbars added.
It seems to be good practice to add some ov-protection to the HP 9825 supply
because the switching transistor and 723 voltage regulators don't have the
eternal life.
And there no certain prediction in how they fail, short or open circuit, I
found out the hard way several years ago.

-Rik

Re: Flex Disc options for the HP 9825

[curiousmarc3]

Thanks for the info. Any schematics of the modification?
Marc


> On Aug 13, 2016, at 2:37 AM, Rik Bos  wrote:
> 
> 
> For what it's worth a small warning about the HP 9825 series computers.
> The power supply doesn't have a crowbar(over voltage protection), so a
> transistor failure in the Psu can be catastrophic.
> On the other hand the two 9835's I have, which uses the same form factor and
> almost the same power supply layout are HP modified with crowbars added.
> It seems to be good practice to add some ov-protection to the HP 9825 supply
> because the switching transistor and 723 voltage regulators don't have the
> eternal life.
> And there no certain prediction in how they fail, short or open circuit, I
> found out the hard way several years ago.
> 
> -Rik
> 

Re: Flex Disc options for the HP 9825

[Paul Berger]

The cable will come with the GPIO, the one you want is the 98032A option 
085, but if you cannot find one of them any 98032A could be reconfigured 
to support  a 9885. Diskettes are going to be a bigger issue, as per 
hpmuseum.net you will need a 9895 to be able to transfer their image to 
a physical diskette.


Paul.



On 2016-08-12 5:30 AM, curiousma...@gmail.com wrote:

I got the HP 9885 single sided disk unit that was at Weird Stuff, thanks for the 
heads up! Now I just need a parallel interface for the 9825, a cable, the right 
8" diskettes, and get my HP-IB 9895 to work... That's a lot of stars to align 
but that should be fun to try.
Marc


On Jul 24, 2016, at 3:30 AM, David Collins <davidk.coll...@bigpond.com> wrote:

Guys, I've looked for a 98228A ROM in the HP Computer Museum but haven't
been able to find one - but it looks like we've had one at some stage
judging by the photo.

If I come across it I'll come back to you.

David Collins
Curator


-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of CuriousMarc
Sent: Saturday, 23 July 2016 5:40 PM
To: 'General Discussion: On-Topic and Off-Topic Posts'
<cctalk@classiccmp.org>
Subject: RE: Flex Disc options for the HP 9825

Thanks, I didn't know, I grabbed the image. That offers a path if I can ever
get an 9885 and single sides 8" discs...
Marc


-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul
Berger On the hpmuseum.net page for the 98217A ROM here is an image of
what is reputed to be an initialized diskette for use with 9825 and
98217A http://www.hpmuseum.net/display_item.php?hw=166. When I get my
9825T I will look into 9885 emulation, I don't think it will be too

difficult but

you may still need a GPIO unless I build the whole thing onto a
plug-in card I don't think the GPIO would be too difficult to clone.
But ideally I would still like to get access to a 98228A ROM to dump
and

clone

it, even though it is bank switched it should still be possible.

Paul.

Re: Flex Disc options for the HP 9825

[curiousmarc3]

I got the HP 9885 single sided disk unit that was at Weird Stuff, thanks for 
the heads up! Now I just need a parallel interface for the 9825, a cable, the 
right 8" diskettes, and get my HP-IB 9895 to work... That's a lot of stars to 
align but that should be fun to try.
Marc

> On Jul 24, 2016, at 3:30 AM, David Collins <davidk.coll...@bigpond.com> wrote:
> 
> Guys, I've looked for a 98228A ROM in the HP Computer Museum but haven't
> been able to find one - but it looks like we've had one at some stage
> judging by the photo. 
> 
> If I come across it I'll come back to you. 
> 
> David Collins 
> Curator
> 
> 
> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of CuriousMarc
> Sent: Saturday, 23 July 2016 5:40 PM
> To: 'General Discussion: On-Topic and Off-Topic Posts'
> <cctalk@classiccmp.org>
> Subject: RE: Flex Disc options for the HP 9825
> 
> Thanks, I didn't know, I grabbed the image. That offers a path if I can ever
> get an 9885 and single sides 8" discs...
> Marc
> 
>> -Original Message-
>> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul 
>> Berger On the hpmuseum.net page for the 98217A ROM here is an image of 
>> what is reputed to be an initialized diskette for use with 9825 and 
>> 98217A http://www.hpmuseum.net/display_item.php?hw=166. When I get my 
>> 9825T I will look into 9885 emulation, I don't think it will be too
> difficult but
>> you may still need a GPIO unless I build the whole thing onto a 
>> plug-in card I don't think the GPIO would be too difficult to clone.
>> But ideally I would still like to get access to a 98228A ROM to dump 
>> and
> clone
>> it, even though it is bank switched it should still be possible.
>> 
>> Paul.
> 
> 

Re: Flex Disc options for the HP 9825

[curiousmarc3]

Thanks for looking!
Marc

> On Jul 24, 2016, at 3:30 AM, David Collins <davidk.coll...@bigpond.com> wrote:
> 
> Guys, I've looked for a 98228A ROM in the HP Computer Museum but haven't
> been able to find one - but it looks like we've had one at some stage
> judging by the photo. 
> 
> If I come across it I'll come back to you. 
> 
> David Collins 
> Curator
> 
> 
> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of CuriousMarc
> Sent: Saturday, 23 July 2016 5:40 PM
> To: 'General Discussion: On-Topic and Off-Topic Posts'
> <cctalk@classiccmp.org>
> Subject: RE: Flex Disc options for the HP 9825
> 
> Thanks, I didn't know, I grabbed the image. That offers a path if I can ever
> get an 9885 and single sides 8" discs...
> Marc
> 
>> -Original Message-
>> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul 
>> Berger On the hpmuseum.net page for the 98217A ROM here is an image of 
>> what is reputed to be an initialized diskette for use with 9825 and 
>> 98217A http://www.hpmuseum.net/display_item.php?hw=166. When I get my 
>> 9825T I will look into 9885 emulation, I don't think it will be too
> difficult but
>> you may still need a GPIO unless I build the whole thing onto a 
>> plug-in card I don't think the GPIO would be too difficult to clone.
>> But ideally I would still like to get access to a 98228A ROM to dump 
>> and
> clone
>> it, even though it is bank switched it should still be possible.
>> 
>> Paul.
> 
> 

RE: Flex Disc options for the HP 9825

[David Collins]

Guys, I've looked for a 98228A ROM in the HP Computer Museum but haven't
been able to find one - but it looks like we've had one at some stage
judging by the photo. 

If I come across it I'll come back to you. 

David Collins 
Curator


-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of CuriousMarc
Sent: Saturday, 23 July 2016 5:40 PM
To: 'General Discussion: On-Topic and Off-Topic Posts'
<cctalk@classiccmp.org>
Subject: RE: Flex Disc options for the HP 9825

Thanks, I didn't know, I grabbed the image. That offers a path if I can ever
get an 9885 and single sides 8" discs...
Marc

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul 
> Berger On the hpmuseum.net page for the 98217A ROM here is an image of 
> what is reputed to be an initialized diskette for use with 9825 and 
> 98217A http://www.hpmuseum.net/display_item.php?hw=166. When I get my 
> 9825T I will look into 9885 emulation, I don't think it will be too
difficult but
> you may still need a GPIO unless I build the whole thing onto a 
> plug-in card I don't think the GPIO would be too difficult to clone.
> But ideally I would still like to get access to a 98228A ROM to dump 
> and
clone
> it, even though it is bank switched it should still be possible.
> 
> Paul.

RE: Flex Disc options for the HP 9825

[CuriousMarc]

Thanks, I didn't know, I grabbed the image. That offers a path if I can ever
get an 9885 and single sides 8" discs...
Marc

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul
> Berger
> On the hpmuseum.net page for the 98217A ROM here is an image of what is
> reputed to be an initialized diskette for use with 9825 and 98217A
> http://www.hpmuseum.net/display_item.php?hw=166. When I get my
> 9825T I will look into 9885 emulation, I don't think it will be too
difficult but
> you may still need a GPIO unless I build the whole thing onto a
> plug-in card I don't think the GPIO would be too difficult to clone.
> But ideally I would still like to get access to a 98228A ROM to dump and
clone
> it, even though it is bank switched it should still be possible.
> 
> Paul.

Re: Flex Disc options for the HP 9825

[Paul Berger]

On 2016-07-22 9:17 PM, CuriousMarc wrote:

Unfortunately, I have the older ROM, the HP 98217A. Says 9885 Flexible Disk
Drive on it (duh). Only this 9885, single side low density 8" drive,
connected with the parallel interface and a special cable is supported. And
indeed as Tony says, to start from a blank disk, you need a tape cartridge
that has the "disc system" on it and run an initialize program to copy files
on the first disc sectors. If you don't have a copy of that cartridge then
you are hosed even with that ROM. So I am hosed twice: I don't have a 9885
drive and I don't have the cartridge. And I suspect a cartridge that's
readable doesn't exist anymore.

The newer ROM is the HP 98228. Which can ONLY work in a later HP 9825T (not
the A nor the B), and can drive the aforementioned 8" 9885 with the parallel
interface, and also the 9895 double sided double density double drive via
the HP-IB interface. But only with the "revised" HP-IB interface, not the
original interface. Very picky that ROM.  Bu for the 9885 disc, it does not
have the cartridge requirement (yeah!). I have the 9825T, the 9895 drive,
the revised interface, but not the right ROM. Hosed again.

The details are in the 9825 Disc ROM Manual:
http://www.hpmuseum.net/document.php?hwfile=1864

Marc
On the hpmuseum.net page for the 98217A ROM here is an image of what is 
reputed to be an initialized diskette for use with 9825 and 98217A 
http://www.hpmuseum.net/display_item.php?hw=166. When I get my 9825T I 
will look into 9885 emulation, I don't think it will be too difficult 
but you may still need a GPIO unless I build the whole thing onto a 
plug-in card I don't think the GPIO would be too difficult to clone.   
But ideally I would still like to get access to a 98228A ROM to dump and 
clone it, even though it is bank switched it should still be possible.


Paul.

RE: Flex Disc options for the HP 9825

[CuriousMarc]

Unfortunately, I have the older ROM, the HP 98217A. Says 9885 Flexible Disk
Drive on it (duh). Only this 9885, single side low density 8" drive,
connected with the parallel interface and a special cable is supported. And
indeed as Tony says, to start from a blank disk, you need a tape cartridge
that has the "disc system" on it and run an initialize program to copy files
on the first disc sectors. If you don't have a copy of that cartridge then
you are hosed even with that ROM. So I am hosed twice: I don't have a 9885
drive and I don't have the cartridge. And I suspect a cartridge that's
readable doesn't exist anymore.

The newer ROM is the HP 98228. Which can ONLY work in a later HP 9825T (not
the A nor the B), and can drive the aforementioned 8" 9885 with the parallel
interface, and also the 9895 double sided double density double drive via
the HP-IB interface. But only with the "revised" HP-IB interface, not the
original interface. Very picky that ROM.  Bu for the 9885 disc, it does not
have the cartridge requirement (yeah!). I have the 9825T, the 9895 drive,
the revised interface, but not the right ROM. Hosed again.

The details are in the 9825 Disc ROM Manual:
http://www.hpmuseum.net/document.php?hwfile=1864

Marc

> > Probably a question for Tony's encyclopedic knowledge. I just scored
> > two HP 9825, one a later "T" option and one "B" version with all the
> > fixings (i.e ROM packs). They both seem to work save the usual tape
> > drive which I have not gotten to yet. Both have the flexible disc ROM.
> > What kind of discs can I hook up?
> 
> Which flexible disk ROM? There are 2. The older one, AFAIK supports the
> HP9885 8" drive which has a 16 bit parallel interface and needs the right
> version of the 98032 to hook it up. The later disk ROM supports the HP9895
> on HPIB.
> 
> The older ROM needs a disk with various programs on it to work, it is
> essentially just a bootstrap. Have any such disks survived?
> 
> -tony

Re: Flex Disc options for the HP 9825

[Curious Marc]

Great info. I'm on travel but I will check which ROMs I have when I come back 
on Friday. 
Marc

> On Jul 19, 2016, at 2:06 PM, tony duell  wrote:
> 
> 
> 
>> Probably a question for Tony's encyclopedic knowledge. I just
>> scored two HP 9825, one a later "T" option and one "B" version 
>> with all the fixings (i.e ROM packs). They both seem to work
>> save the usual tape drive which I have not gotten to yet. Both
>> have the flexible disc ROM. What kind of discs can I hook up?
> 
> Which flexible disk ROM? There are 2. The older one, AFAIK 
> supports the HP9885 8" drive which has a 16 bit parallel interface
> and needs the right version of the 98032 to hook it up. The later
> disk ROM supports the HP9895 on HPIB.
> 
> The older ROM needs a disk with various programs on it to
> work, it is essentially just a bootstrap. Have any such disks
> survived?
> 
> -tony

Re: Flex Disc options for the HP 9825

[Paul Berger]

On 2016-07-19 2:25 PM, tony duell wrote:

There was only ever support for 8" diskette drives, and to support 9895
you need the second version of the Diskette ROM which appears to be very
rare.  I t sure would be nice if someone who has one of these ROMs would
dump the contents or loan it to someone who could dump it, so that we
might be able to clone the ROM module.

It's not totally trivial. The later version module is so large that part of the
ROM is bank-switched. So you would have to make sure you copied the
entire ROM and the copied the bank-switching circuitry in the cloned
module.

-tony
Yes I saw your schematic, it does not seem too big of a challenge, but 
on the other hand it may be bank switched just because it supports both 
diskette drives and both halve may not be required to support only 9895, 
but without a dump that is only speculation.


Paul.

Re: Flex Disc options for the HP 9825

[Paul Berger]

On 2016-07-19 1:25 AM, Curious Marc wrote:

Probably a question for Tony's encyclopedic knowledge. I just scored two HP 9825, one a later "T" 
option and one "B" version with all the fixings (i.e ROM packs). They both seem to work save the 
usual tape drive which I have not gotten to yet. Both have the flexible disc ROM. What kind of discs can I 
hook up? I think the HP 9895 8" floppy would work. What about the HP 82901 5.25" floppy drive? How 
do I read/write program files from the disc interface?
Marc

Sent from my iPad
There was only ever support for 8" diskette drives, and to support 9895 
you need the second version of the Diskette ROM which appears to be very 
rare.  I t sure would be nice if someone who has one of these ROMs would 
dump the contents or loan it to someone who could dump it, so that we 
might be able to clone the ROM module.


Paul.

Re: Flex Disc options for the HP 9825

[Paul Berger]

On 2016-07-19 2:06 AM, tony duell wrote:



Probably a question for Tony's encyclopedic knowledge. I just
scored two HP 9825, one a later "T" option and one "B" version
with all the fixings (i.e ROM packs). They both seem to work
save the usual tape drive which I have not gotten to yet. Both
have the flexible disc ROM. What kind of discs can I hook up?

Which flexible disk ROM? There are 2. The older one, AFAIK
supports the HP9885 8" drive which has a 16 bit parallel interface
and needs the right version of the 98032 to hook it up. The later
disk ROM supports the HP9895 on HPIB.
The only difference between the different versions of 98032A is the 
cable and some jumpers inside but it appears to all be documented so 
even if you don't have the option 085 98032A, the 50 pin D shell 
connector used on the 9885 is pretty common.


The older ROM needs a disk with various programs on it to
work, it is essentially just a bootstrap. Have any such disks
survived?

There is an image of one on the hpmuseum.net site.


-tony

Paul.