12 May
2020
12 May
'20
12:15 a.m.
Hi all --
I'm restoring a Xerox Alto and I started going over the system's Diablo 30
drive. The heads are in bad shape; the bottom one is actually missing both
parts of the erase poles (so the black portion of the head no longer makes
a "t", it's just a black line). This means the head (in addition to not
being able to erase) also won't float due to the head having small cavities
in them. The upper head looks a little better but I'd love to find a set
of upper and lower heads if anyone has spares.
Then I get to learn how to align these things.
Thanks!
- Josh
12 May
12 May
1:18 a.m.
On 5/11/2020 9:15 PM, Josh Dersch via cctalk wrote:
Hi all --
I'm restoring a Xerox Alto and I started going over the system's Diablo 30
drive. The heads are in bad shape; the bottom one is actually missing both
parts of the erase poles (so the black portion of the head no longer makes
a "t", it's just a black line). This means the head (in addition to not
being able to erase) also won't float due to the head having small cavities
in them. The upper head looks a little better but I'd love to find a set
of upper and lower heads if anyone has spares.
This guy has had several of many of
the types of heads you need. This is
for a Microdata or Western Dynex of either the 2.5m / platter or 5m /
platter variety.? Might bug him
MICRODATA-PN-20012187-3-NSN-1560-00-121-8703-DISK-HEAD-NEW-ORIG-BX-selectvintage/
https://www.ebay.com/itm/192169612454
Here's the list of stuff he has with all the heads.? There may be
equivalents in there, don't know.
https://www.ebay.com/sch/Computers-Tablets-Networking/58058/m.html?item=192…
selectvintage is vendor.
Then I get to learn how to align these things.
I've got one that would fit an
RL02 and possibly an RL01, does work with
Dynex or Microdata.
you might have to find an exerciser, and option the drive to the # of
sectors.
You can get it playing with a recorded but expendable pack.? That is
with a Microdata drive.? Maybe someone can also record some ones and
zeros for the amp calibrations.? I don't know if they are doing the
embedded servo thing or not, or the drive might choke on something.
I've gotten them going by setting up the basic drive function w/o
alignment, so it can pass a formatting tests (again, not with embedded
servo) on a blank pack.
Then you use the tester and the alignment and analog section with a data
pack (not necessarily alignment) that has good data on it.? You can get
by w/o an alignment pack that way.
thanks
jim
Thanks!
- Josh
9:10 a.m.
On 5/11/2020 11:15 PM, Josh Dersch via cctalk wrote:
Hi all --
I'm restoring a Xerox Alto and I started going over the system's Diablo 30
drive. The heads are in bad shape; the bottom one is actually missing both
parts of the erase poles (so the black portion of the head no longer makes
a "t", it's just a black line). This means the head (in addition to not
being able to erase) also won't float due to the head having small cavities
in them. The upper head looks a little better but I'd love to find a set
of upper and lower heads if anyone has spares.
Then I get to learn how to align these things.
Thanks!
- Josh
I don't know if they would be compatible or not, but my inventory lists
Diablo part number 15428, Model 31 / RK03 Carriage + Heads Assembly.
(Perhaps I didn't want to remove the heads themselves). I suspect that
I got the part number off the assembly itself somewhere - I don't have
record of any illustrated parts breakdown for the diablo drive in my
manual database.
As I seem to have two of these assemblies, you could certainly have one
of them, say for something like shipping plus $25.
I don't know the differences between the model 30 and model 31 - but as
the capacity of the model 31 was apparently twice that of the model 30
(2.5MB vs 1.25MB) - with both being referred to as Series 30, with the
model 30 apparently short-lived production wise. The Series 30
maintenance manual, on the other hand, lists "Standard" and
"HI-Density"
of 12 million bits and 24 millions bits, respectively.
From what I read of the Alto online, its disk capacity
was 2.5MB -
implying the drive is a model 31 / hi density.
I don't remember now if these parts I have were from drives originally
on a DEC or DG system. If they really were from RK03's, then they would
be the high density flavor.
The box they are in are off-site in my storage unit (but well stored),
and I could retrieve them in a day or so if you are interested, but at
present I don't know if this is the entire assembly shown on page 5-3 of
the maintenance manual, or just a portion.
PS: I seem to recall a "Curious Marc" YouTube video featuring these
beasties along with the Alto they were part of.
JRJ
10:26 a.m.
On 5/12/20 6:10 AM, Jay Jaeger via cctalk wrote:
I don't remember now if these parts I have were
from drives originally
on a DEC or DG system.
The easy way to tell is the low density heads have metal instead of ceramic disks.
If anyone has the older metal style, Carl Claunch is trying to find some.
13 May
13 May
3:26 a.m.
I have Diablo 30 or 31 and 2 RK11-C backplanes here. If anyone here is
interested, please contact me off list.
2:49 p.m.
i've uploaded what the high density heads look like to
http://bitsavers.org/pdf/diablo/photos/heads
9:28 p.m.
On 5/12/2020 9:26 AM, Al Kossow via cctalk wrote:
On 5/12/20 6:10 AM, Jay Jaeger via cctalk wrote:
It turns out mine a metal, and perhaps came off of a DG system (my
RK03's on a PDP-11 have ceramic heads.)
Carl, feel free to contact me off list.
JRJ
I don't remember now if these parts I have
were from drives originally
on a DEC or DG system.
The easy way to tell is the low density heads have metal instead of
ceramic disks.
If anyone has the older metal style, Carl Claunch is trying to find some.
14 May
14 May
10:43 a.m.
I wonder if a high density head could be used on a low density machine. I'd think the
main difference would be track width. If the signal levels were similar it might work.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Jay Jaeger via cctalk
<cctalk at classiccmp.org>
Sent: Wednesday, May 13, 2020 6:28 PM
To: cctalk at classiccmp.org <cctalk at classiccmp.org>
Subject: Re: ISO: Diablo 30 heads
On 5/12/2020 9:26 AM, Al Kossow via cctalk wrote:
On 5/12/20 6:10 AM, Jay Jaeger via cctalk wrote:
It turns out mine a metal, and perhaps came off of a DG system (my
RK03's on a PDP-11 have ceramic heads.)
Carl, feel free to contact me off list.
JRJ
I don't remember now if these parts I have
were from drives originally
on a DEC or DG system.
The easy way to tell is the low density heads have metal instead of
ceramic disks.
If anyone has the older metal style, Carl Claunch is trying to find some.
10:57 a.m.
On 5/14/20 7:43 AM, dwight via cctalk wrote:
I wonder if a high density head could be used on a low
density machine. I'd think the main difference would be track width.
It wouldn't work well at all for interchange with a real IBM 1130 disk drive, which
would be what Carl would need them for
11:46 a.m.
On 05/14/2020 09:43 AM, dwight via cctalk wrote:
I wonder if a high density head could be used on a low
density machine. I'd think the main difference would be track width. If the signal
levels were similar it might work.
A high density head should be able to READ a pre-written
low-density pack, assuming the bit rate is the same, just
the track density is the difference.
And, you could probably format and write a pack on a low
density drive with high-density heads.
But, you definitely would have trouble trying to write to a
low-density pre-written pack with high-density heads, as the
erase head would not completely erase the older, wider,
track data. Unless the head positioning was incredibly
reproducible, the old data would contaminate the
newly-written data.
Jon
20 May
20 May
3:46 p.m.
New subject: VT240 and LK201BA available
I have a VT240 with LK201BA available in the St. Louis, MO
area, if anyone is interested.
I do not have the monitor that originally went with it.
But, I think it will take any generic
RS-170 monochrome monitor. It did work last time I used it,
which was at least a decade
ago.
Jon
3:45 p.m.
I just emailed him an hour ago and he replied. I suspect he is fine.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Al Kossow via cctalk
<cctalk at classiccmp.org>
Sent: Thursday, May 14, 2020 9:54 AM
To: cctalk at classiccmp.org <cctalk at classiccmp.org>
Subject: Re: ISO: Diablo 30 heads
On 5/13/20 6:28 PM, Jay Jaeger via cctalk wrote:
Carl, feel free to contact me off list.
Has anyone heard anything from Carl?
I'm a bit concerned since there have been no updates on his 1130 page for a while.
6:31 p.m.
I chatted with him on FB earlier in the day and he's doing fine.
TTFN - Guy
On Thu, 2020-05-14 at 19:45 +0000, dwight via cctalk wrote:
I just emailed him an hour ago and he replied. I
suspect he is fine.
Dwight
________________________________
From: cctalk <cctalk-bounces at classiccmp.org> on behalf of Al Kossow
via cctalk <cctalk at classiccmp.org>
Sent: Thursday, May 14, 2020 9:54 AM
To: cctalk at classiccmp.org <cctalk at classiccmp.org>
Subject: Re: ISO: Diablo 30 heads
On 5/13/20 6:28 PM, Jay Jaeger via cctalk wrote:
Carl, feel free to contact me off list.
Has anyone heard anything from Carl?
I'm a bit concerned since there have been no updates on his 1130 page
for a while.
1473
days inactive
1481
days old
13 comments
8 participants
participants (8)
-
aek＠bitsavers.org -
cube1＠charter.net -
derschjo＠gmail.com -
dkelvey＠hotmail.com -
elson＠pico-systems.com -
ggs＠shiresoft.com -
jwsmail＠jwsss.com -
useddec＠gmail.com