10 Mar
2005
10 Mar
'05
11:25 p.m.
I need some advice on finding a few expendables:
* non-lint swabs for cleaning hard disk heads. I've googled a
bunch of likely suspects, intended for the electronics industry,
of appropriate size, but does anyone use such a thing you've found
to be suitable, before I leap into the terrifying unknown (all of
$9.95's worth)? Obviiously to be dunked in 99% isopropyl.
* "Rotron Filtercoat". Sticky aerosol goo you spray onto aluminum
mesh filters to trap dust. My lab is really dusty. The rack has a
nice airbox at the bottom with noisy fan. Any suggestions as to a
replacement for this long-lost product or workalike?
11 Mar
11 Mar
1:11 a.m.
On Thu, 10 Mar 2005, Tom Jennings wrote:
I need some advice on finding a few expendables:
* non-lint swabs for cleaning hard disk heads. I've googled a
bunch of likely suspects, intended for the electronics industry,
of appropriate size, but does anyone use such a thing you've found
to be suitable, before I leap into the terrifying unknown (all of
$9.95's worth)? Obviiously to be dunked in 99% isopropyl.
Back in my film business days, we used boxes of a product called
"Kimwipes" - several varieties/sizes - some lint-free, and they were,
too!.
Cheers
John
1:43 a.m.
We use Kimwipes where I work. (General Dynamics AIS)
on 3/10/05 11:11 PM, John Lawson at jpl15 at panix.com wrote:
On Thu, 10 Mar 2005, Tom Jennings wrote:
I need some advice on finding a few expendables:
* non-lint swabs for cleaning hard disk heads. I've googled a
bunch of likely suspects, intended for the electronics industry,
of appropriate size, but does anyone use such a thing you've found
to be suitable, before I leap into the terrifying unknown (all of
$9.95's worth)? Obviiously to be dunked in 99% isopropyl.
Back in my film business days, we used boxes of a product called
"Kimwipes" - several varieties/sizes - some lint-free, and they were,
too!.
Cheers
John
4:28 p.m.
We use Kimwipes where I work. (General Dynamics AIS)
I have those too, I was thinking specifically about swabs for
hard-disk heads. Currently I wrap kimwipes around a popsicle stick
(aka craft sticks, very useful things to have in a lab!).
I should have been more specific; this is for Diablo-type
removable 14" cartridge type drives.
6:07 p.m.
>>>> "Tom" == Tom Jennings
<tomj at wps.com> writes:
> We use Kimwipes where I work. (General Dynamics
AIS)
Tom> I have those too, I was thinking specifically about swabs for
Tom> hard-disk heads. Currently I wrap kimwipes around a popsicle
Tom> stick (aka craft sticks, very useful things to have in a lab!).
That's how it was done. I don't remember any swabs; when heads needed
cleaning the FE's would wrap a Kimwipe (tm, presumably) around a stick
just as you described.
paul
11:23 p.m.
On Fri, 11 Mar 2005 18:07:56 -0500
Paul Koning <pkoning at equallogic.com> wrote:
I can remember that in the crude old days in the COM (Computer Output to
Microfilm) shop I worked in from 1978-84, operators would do things like
tape swatches of Kimwipes tightly over the head of the tape drive, to
get hold flaky tapes down tighter against the head. If you've never
held a Kimwipe pressed to the tape/head while the drive flitted back and
forth get a customer's flaky tape to read, you've not worked in data
processing hell. It actually worked.
(I worked as an operator in Computer Micrographics, basically as a
combination 'tape mounting monkey/film processor who operated the
machines that made microfiche from customer data delivered on big reels
of tape.' Fascinating operation it was, and hanging around the CEs was
what convinced me to enroll in Tech School. One of the brands of camera
we had used the PDP8 as the processor. I fondly remember that there was
one drive that was special because it would read the 6250 bpi tapes. We
also had drives with combo 7/9 track heads)
>>>> "Tom" == Tom Jennings <tomj at wps.com> writes:
> We use Kimwipes where I work. (General
Dynamics AIS)
Tom> I have those too, I was thinking specifically about swabs
for
Tom> hard-disk heads. Currently I wrap kimwipes around a popsicle
Tom> stick (aka craft sticks, very useful things to have in a lab!).
That's how it was done. I don't remember any swabs; when heads needed
cleaning the FE's would wrap a Kimwipe (tm, presumably) around a stick
just as you described.
paul
7:13 a.m.
On Thu, 2005-03-10 at 20:25 -0800, Tom Jennings wrote:
* "Rotron Filtercoat". Sticky aerosol goo
you spray onto aluminum
mesh filters to trap dust. My lab is really dusty. The rack has a
nice airbox at the bottom with noisy fan. Any suggestions as to a
replacement for this long-lost product or workalike?
Hmm, possibly spray-mount / photo-mount, or maybe spray-on automotive
carpet glue (latter will be much thicker). I've got a feeling that
they'll remain tacky, so might do the job.
Isn't about 60% of dust made up from dead skin cells? Yum. :-)
cheers
J.
6:37 p.m.
Hellos,
Something broke and I wasn't getting the list for several weeks.. so far, it appears
that I am 'back'..
On Fri, 11 Mar 2005 12:13:44 +0000
Jules Richardson <julesrichardsonuk at yahoo.co.uk> wrote:
On Thu, 2005-03-10 at 20:25 -0800, Tom Jennings
wrote:
You do not want to use a glue or adhesive for this; when time comes to clean & re-oil
the filter, you will never get it off..
I'd suggest using one of the aerosol air filter oils, like the stuff produced by
K&N or Spectro. These oils are bourne in solvent, and when the solvent evaporates, it
leaves behind a sticky oil film that traps dirt.
Like most cleanable filters, they filter best when slightly loaded up. The larger pieces
of trapped dust help to grab the smaller ones, etc. And when it is time to clean up, you
just use something like tri-clor or even kerosense to dissolve the old oil & dirt off
of it. Not easy if you had used an adhesive.
Hope this helps,
--
---------------------------------------------
-. William W. Layer .- -. St. Paul, MN USA .-
---------------------------------------------------
-. Cheif bottlewasher, Atma-Sphere Music Systems .-
-. http://www.atma-sphere.com .-
--------------------------------
* "Rotron Filtercoat". Sticky aerosol
goo you spray onto aluminum
mesh filters to trap dust. My lab is really dusty. The rack has a
nice airbox at the bottom with noisy fan. Any suggestions as to a
replacement for this long-lost product or workalike?
Hmm, possibly spray-mount / photo-mount, or maybe spray-on automotive
carpet glue (latter will be much thicker). I've got a feeling that
they'll remain tacky, so might do the job.
12 Mar
12 Mar
4:38 p.m.
On Fri, 11 Mar 2005, William Layer wrote:
You do not want to use a glue or adhesive for this;
when time comes to clean & re-oil the filter, you will never get it off..
I'd suggest using one of the aerosol air filter oils, like the stuff produced by
K&N or Spectro. These oils are bourne in solvent, and when the solvent evaporates, it
leaves behind a sticky oil film that traps dirt.
Oh yeah, glues would be bad, it needs to be water soluable.
The automotive K&N stuff -- great idea! Probably crappy old
AutoZone has it (the "tuner" kids by all that crap). Same problem,
right solution.
18 Mar
18 Mar
11:16 a.m.
* non-lint swabs for cleaning hard disk heads.
I've googled a
bunch of likely suspects, intended for the electronics industry,
of appropriate size, but does anyone use such a thing you've found
to be suitable, before I leap into the terrifying unknown (all of
$9.95's worth)? Obviiously to be dunked in 99% isopropyl.
We used Texwipe products for cleaning tape heads, the platter chambers
of removable drives, etc. in the mid-late 80's. Not sure we ever
actually used them on disk heads. They make swabs on sticks, as well
as wipes, a kazillion variations.
* "Rotron Filtercoat". Sticky aerosol goo
you spray onto aluminum
mesh filters to trap dust. My lab is really dusty. The rack has a
nice airbox at the bottom with noisy fan. Any suggestions as to a
replacement for this long-lost product or workalike?
We occasionally used Endust for this kind of thing.
De
11:12 a.m.
New subject: vt278
Hi people;
I found a couple of damaged/parts-scavenged qbus boards which
I was able to identify as vt278 (decmate) cpu boards. I searched
the web and came upon documentation at bitsavers and
elsewhere. So it is pdp8-based, using the Harris chips.
1) I found the parts-layout and parts list and have been able
to identify most of the missing chips, except for the
one labeled "E63" in the parts layout schematic,
near the center of the board. This chip is not explained
in the parts list. Does anybody know what it is?
(it is the 18 pin chip to the left of pin 1 of the lower D3-6121-9A
chip, which in turn is the lowermost of the four 40 pin DIP chips
by Harris; this is when looking at the component side with
the slot tabs pointing downwards)
2) Can one use this board to run older pdp8 software?
Can one connect a terminal to the printer port with
some special cable, supply power to the board and
have the thing come back alive and talk to the terminal?
I don't have a qbus backplane, so I was just thinking about
repairing the board, repopulate it and connect power at the
appropriate points.
(the diagrams are at http://www.bitsavers.org/pdf/dec/pdp8/cmos8/,
file MP00900_VT278_may81.pdf)
--
Carlos E. Murillo-Sanchez email: carlos_murillo at nospanners.ieee.org
Dean of Engineering, Universidad Autonoma de Manizales, Manizales, Colombia
----
"Western civilization... thought like the greeks, organized itself like
the romans and believed in itself like the hebrew." -- Ortega y Gasset.
1:14 p.m.
New subject: vt278
1) I found the parts-layout and parts list and have
been able
to identify most of the missing chips, except for the
one labeled "E63" in the parts layout schematic,
near the center of the board. This chip is not explained
in the parts list. Does anybody know what it is?
(it is the 18 pin chip to the left of pin 1 of the lower D3-6121-9A
chip, which in turn is the lowermost of the four 40 pin DIP chips
by Harris; this is when looking at the component side with
the slot tabs pointing downwards)
Mine has an empty socket there. Looks from how it is wired that it is meant
to take another m1-6322-9, like the three above it. (Perhaps an option
ROM?)
2) Can one use this board to run older pdp8 software?
Yes (some).
Can one connect a terminal to the printer port with
some special cable, supply power to the board and
have the thing come back alive and talk to the terminal?
I don't think it wants to talk there (without extensive firmware work). It
wants to plug into the terminal backplane (which I am sure is *not* qbus),
with a keyboard plugged into it.
I don't have a qbus backplane, so I was just
thinking about
repairing the board, repopulate it and connect power at the
appropriate points.
From what I have read, that could be a challenge. It
would probably be
easier to build a compatible video adapter and keyboard stuff for
it. The
floppy is an RX01 with a special cable, IIRC.
Vince
1:41 p.m.
New subject: vt278
On Fri, 18 Mar 2005, vrs wrote:
Good, then I was probably looking for a chip that was never there.
great, I will probably ask for more clarification on this later on..
Ok. It's been a while since I've had a Qbus card in
my hands and this card really looked like one. Too bad that
it won't accept a diagnostics terminal like the microvaxen.
Unfortunately I did not find the rest of the terminal.
There's a socket for a 5037 video crt controller in the card (which is
also missing). What is the 1/4" plug connector for?
Carlos.
by Harris;
this is when looking at the component side with
the slot tabs pointing downwards)
Mine has an empty socket there. Looks from how it is wired that it is meant
to take another m1-6322-9, like the three above it. (Perhaps an option
ROM?) 2) Can one use
this board to run older pdp8 software?
Yes (some). Can one connect a terminal to the printer port
with
I don't think it wants to talk there (without extensive firmware work). It
wants to plug into the terminal backplane (which I am sure is *not* qbus),
with a keyboard plugged into it. From what I
have read, that could be a challenge. It would probably be
easier to build a
compatible video adapter and keyboard stuff for it. The
floppy is an RX01 with a special cable, IIRC. 
5:42 p.m.
New subject: vt278
On Fri, 18 Mar 2005 13:41:50 -0500 (EST), Carlos E. Murillo-Sanchez
<carlos at jimulco.autonoma.edu.co> wrote:
Ok. It's been a while since I've had a Qbus
card in
my hands and this card really looked like one. Too bad that
it won't accept a diagnostics terminal like the microvaxen.
It may have the same shaped edge fingers as a Qbus card, but it's not Qbus.
Unfortunately I did not find the rest of the terminal.
That's a shame.
There's a socket for a 5037 video crt controller
in the card (which is
also missing).
Hmm... there you go... that answers my earlier question... it wants to
generate its own video... if you can find a replacement 5037, you
could probably tap off the other end of that circuit and feed it to a
VR201 or any other "standard" NTSC / RS-170 mono monitor.
What is the 1/4" plug connector for?
VT100 keyboard.
-ethan
5:40 p.m.
New subject: vt278
On Fri, 18 Mar 2005 10:14:57 -0800, vrs <vrs at msn.com> wrote:
The version of OS/8 for that board is termed "OS/278" - there are some
fundamental differences with how that design implements the console
IOT instructions and how those same instructions were implemented on
older machines. As a result, most code that talks to the console
terminal needs to be updated to work with any DECmate. It's a trivial
change to the code, but if it is not done, IIRC, old code either
clears the recently sent character or fails to notice that a new
character is available or something equally dire.
In any case, unmodified OS/8 will not work properly on a DECmate.
Not as far as I know... the console firmware expects a certain device
environment to be present. Now... unlike the later DECmates, it
_might_ be possible to tap off of the CPU board the right signals to
talk to an external terminal, but it won't be off the printer port.
It wouldn't be the right device pair (03/04), anyway, for applications
to work.
The part I don't remember is how much of the VT100 circuitry is on the
DECmate I CPU board... In the case of a VT103 (with a _real_ Qbus),
100% of a VT100 is present inside the case, and there's an optional
internal card to plug into an odd white socket on the VT100 board that
lets you reach internal signals, removing the requirement for external
serial cabling for the CPU in the VT103, but the DECmate I is not the
same design. If one establishes how much of the VT100 part is on the
CPU board, one could make a better determination about how much stuff
has to be hung off the DECmate I board to make it work. Since I think
the DEC keyboard plugs right into the CPU card, IIRC, I would expect
that one would at least have to use a VT100-compatible keyboard as a
start, but perhaps one could just attach a frequency-compatible mono
monitor to the CPU board and have a system.
There are other options possible, so many of those edge finger signals
are designed to talk to things like the communications option board (4
extra serial ports?) or the RL02 controller. I'd _love_ to get the
RL02 controller for my DM I, but I've never seen one for sale. :-(
The cable is well documented, and there are two types - one is
DC37-to-DB25 for a single drive, another is a Y cable with *two* DB-25
ends. One typically set the DM I on top of a pedestal-mount RX02
setup that has room for one or two complete RX02 mechanisms. It's
available with a hang-on-the-front keyboard tray, or a
hang-on-the-front (now the side) desktop bracket. I have the desk and
desktop bracket with mine. In that configuration, the RX02 drives
face the user. From my rummaging around years ago, I am fairly
certain that one can dismantle a rack-mount RX02 and install it in a
DM pedestal, but I haven't tried that personally. It _is_ all the
same parts, but it _might_ need a longer cable harness for internal
power.
AFAIK, DEC only had one pinout for RX02 signals over a DB25 cable...
There seems to be one DB25F-to-Berg 40 board, one or two of which can
be found in the DM pedestal, and one can be found in the MINC-11
tabletop RX02 enclosure. So if one has a MINC-11 with drives, one can
borrow the drives for use with a DECmate I.
WPS-8 was much more commonly used with the DECmate I than any other OS
that I am aware of. If you don't need to read WPS disks, I can't
imagine why one would subject oneself to such a product for modern
production use, but twenty years ago, people did write papers,
letters, etc. with WPS-8, and it will still do so today. I would only
recommend it as an exercise for the curious... it is not even close to
WYSIWYG, and the manuals are quite thick.
If you do determine that you could provide power (probably +5VDC and a
couple alternate voltages for RS-232 like +/-12VDC at low amperage),
and it's possible to tap off some sort of RS-170-compatible video
signal, it's likely that you could put this bare board to use as an
expansionless DECmate I... if there are any active video circuits in
the remander of the DECmate I, though, you'd have to provide them
somehow. I suppose one could recode the firmware, but that wouldn't
be a simple task to reverse-engineer the ROMs to the point that one
could make the necessary changes.
-ethan
2) Can one use
this board to run older pdp8 software?
Yes (some). Can one
connect a terminal to the printer port with
some special cable, supply power to the board and
have the thing come back alive and talk to the terminal?
I don't think it wants to talk there (without extensive firmware work). It
wants to plug into the terminal backplane (which I am sure is *not* qbus),
with a keyboard plugged into it. I don't
have a qbus backplane, so I was just thinking about
repairing the board, repopulate it and connect power at the
appropriate points.
From what I have read, that could be a challenge.
It would probably be
easier to build a compatible video adapter and keyboard stuff
for it. The
floppy is an RX01 with a special cable, IIRC. 
21 Mar
21 Mar
12:49 a.m.
New subject: vt278
On Fri, 18 Mar 2005 11:12:49 -0500, Carlos Murillo
<cmurillo at manizales.autonoma.edu.co> wrote:
Hi people;
I found a couple of damaged/parts-scavenged qbus boards which
I was able to identify as vt278 (decmate) cpu boards...
Can one connect a terminal to the printer port with
some special cable, supply power to the board and
have the thing come back alive and talk to the terminal?
(the diagrams are at http://www.bitsavers.org/pdf/dec/pdp8/cmos8/,
file MP00900_VT278_may81.pdf)
Carlos,
From looking at the prints, I can see where the video
chip pumps out H
sync, V sync, and video to the edge fingers... the board also
needs
+5, +12 and -12 (for the DRAMs, among other uses). It's been years
since I tore apart a VT100 (was turning two dead ones into one live
one), but there's nothing magical about them... the video board
schematic is in the VT278 drawings. If you didn't want to muck around
inside a real VT100, you'd need a mono video monitor that can handle
the sync rates for 80 col and 132 col, whatever they happen to be
(never poked at the video signals with an o-scope, so can't even
hazard a guess).
If you decide that it would be too much trouble to get that 'naked'
VT278 board working, feel free to let me know... I wouldn't mind a
spare for my DECmate I.
-ethan
6:53 p.m.
New subject: vt278
From looking at
the prints, I can see where the video chip pumps out H
sync, V sync, and video to
the edge fingers... the board also needs
+5, +12 and -12 (for the DRAMs, among other uses). It's been years
since I tore apart a VT100 (was turning two dead ones into one live
one), but there's nothing magical about them... the video board
schematic is in the VT278 drawings. If you didn't want to muck around
inside a real VT100, you'd need a mono video monitor that can handle
the sync rates for 80 col and 132 col, whatever they happen to be
(never poked at the video signals with an o-scope, so can't even
hazard a guess).
7058
days inactive
7068
days old
17 comments
14 participants
participants (14)
-
ard＠p850ug1.demon.co.uk -
carlos＠jimulco.autonoma.edu.co -
chenmel＠earthlink.net -
cmurillo＠manizales.autonoma.edu.co -
drb＠msu.edu -
eric＠brouhaha.com -
ethan.dicks＠gmail.com -
jpl15＠panix.com -
julesrichardsonuk＠yahoo.co.uk -
pkoning＠equallogic.com -
tomj＠wps.com -
vrs＠msn.com -
william.layer＠comcast.net -
willisjo＠zianet.com