>From: "Jules Richardson" <julesrichardsonuk at yahoo.co.uk>
---snip---
>
>I've been using sewing machine oil so far (which is the lightest stuff
>I've got). I just wonder if leaving it in a (slowly circulating /
>filtered?) bath of oil for a week or so would be useful for freeing
>stuff up and getting all the dirt out...
Hi
You might try first removing any rubber parts and then
soak the entire assembly in a pan of oil. You might use
straight weight motor oil and dilute it down with a little
kerosene. Let it sit for some time and then work it manually
while in the oil. This helps to wash things out, like rust
and little bits of abrasive material.
Tony might want to comment on this, he has worked on more
mechanical items than I have.
>
>
>> > So far I've found an acorn jamming up the works (!!) and lots of dirt,
>>
>> An Acorn... What, a System 1, or an Atom, or a Beeb or an Arch, or what...
>>
>> (sorry, couldn't resist...)
>
>:-)
>
>I have no idea how it got in there; there isn't really a sufficient gap
>anywhere for such a thing to fall inside. And it was *very* well buried
>inside the mechanism (almost as though someone stuck it in there for
>fun!)
---snip---
This was most likely done by a mouse. They like to stash these
nuts in some of the damnedest places. I had to clean a pile of
nuts from my IMSAI power supply and find the small opening my
little friend used to transport them in.
Dwight
>From: "Randy McLaughlin" <cctalk at randy482.com>
---snip---
>
>As I said my recommendation it to set it up then test it, change things and
>test again.
>
I have one of those nice Fluke multiple input meters
with several thermocouple wires. It makes it easy to
check things.
On covering the power supply side, I leave about 1/4
of the air slots open towards the front panel.
Randy is right that each installation requires a
little different approach. If the machine is
sparsely populated, one might even add some
blocking to parts of the card cage. Air flow is a real
funny thing. Air flow from a muffin fan is funnier
still.
Do remember, most power supply parts, such as diodes
and transformers are more tolerant to temperature
than your 20 year old memory chips.
Dwight
>From: "Brian Knittel" <brian at quarterbyte.com>
>
>> ... I recently read that operators would rub a bit of nose oil on
>> the sticky or unreadable spot on the tape
>
>Is that the expensive stuff you buy in a little bottle,
>they call it Attar of Noses?
Hi
This may have worked for reading but my experience is
that any finger or nose grease will make recording
fail on cassette tapes.
Dwight
Hi
One should note that unless the fan is blowing directly onto
some particularly hot item, you'll get really poor air flow
distribution by blowing with a muffin fan. First the fast moving
air tended to stick to the first surface it finds ( Coanda effect ).
Also the air is rotation that tends to cause it to find corners
to travel along.
When the air is pulls into the fan, it tends to have more
laminar flow from all directions.
For better all around cooling, I recommend taping or masking
off most of the slots on the power supply side, near the fan
( for a IMSAI or Atair ). These keep the air from cheating by
taking the path of least resistance. More air flows across the
boards and along the power supply.
Dwight
>From: "Dave Dunfield" <dave04a at dunfield.com>
>
>At 21:31 16/06/2005 -0400, you wrote:
>>All:
>>
>> OK, this is a stupid question. I'm fixing up the 8800b that I got
>>recently and I removed the fan to perform some work on the power supply.
>>Unfortunately I didn't mark which direction the air blows. Can someone tell
>>me if it blows inward or outward?
>>
>> Thanks.
>>
>>Rich
>
>Hi Rich,
>
>Both of my 8800s have the fan blowing out.
>
>The general rule is:
>
>If the fan has a filter, then it should blow in.:
>
> By maintaining positive internal pressure, and
> filtering the air that comes in, you keep dust
> from entering the box.
>
>If it does not have a filter, it should blow out:
>
> A fast moving stream of air will carry more dust
> than a slow one. If you blow the fan in, it will
> carry dust into the box which will drop out before
> it exits at slower speed (because of the much larger
> area of all the vents and other openings) - it also
> causes dust buildup to concentrate that certain
> points bacause of sudden changes in airflow (you can
> often see bands of thick dust in boxes with fans
> improperly installed). Going the other way reduces
> the entry speed (same reason) and thus the amount of
> dust that enters - what does get in tends to settle
> out in a more uniform distribution.
>
>Regards,
>Dave
>--
>dave04a (at) Dave Dunfield
>dunfield (dot) Firmware development services & tools: www.dunfield.com
>com Collector of vintage computing equipment:
> http://www.parse.com/~ddunfield/museum/index.html
>
>
>
> ... I recently read that operators would rub a bit of nose oil on
> the sticky or unreadable spot on the tape
Is that the expensive stuff you buy in a little bottle,
they call it Attar of Noses?
Hi,
I have a copy of Windows 3.0 for DOS, in its original
box. Not sure if it has a value on eBay, but just
wondered if anybody wanted it (paying the cost of
postage and packing) as I'm likely to bin it
otherwise.
Thanks,
Roger
___________________________________________________________
Yahoo! Messenger - NEW crystal clear PC to PC calling worldwide with voicemail http://uk.messenger.yahoo.com
Dwight:
Interestingly, on the IMSAI, the slotted vents on the power supply
side are blocked to prevent the "path cheating" you alluded to. Also the
inside of the IMSAI case was virtually spotless with an inward-blowing fan
(and no filter) while the Altair, which I believe had an inward-blowing fan,
was filthy.
Rich
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
On Behalf Of Dwight K. Elvey
Sent: Friday, June 17, 2005 1:08 PM
To: cctalk at classiccmp.org
Subject: Re: Altair Fan
Hi
One should note that unless the fan is blowing directly onto
some particularly hot item, you'll get really poor air flow
distribution by blowing with a muffin fan. First the fast moving
air tended to stick to the first surface it finds ( Coanda effect ).
Also the air is rotation that tends to cause it to find corners
to travel along.
When the air is pulls into the fan, it tends to have more
laminar flow from all directions.
For better all around cooling, I recommend taping or masking
off most of the slots on the power supply side, near the fan
( for a IMSAI or Atair ). These keep the air from cheating by
taking the path of least resistance. More air flows across the
boards and along the power supply.
Dwight
>From: "Dave Dunfield" <dave04a at dunfield.com>
>
>At 21:31 16/06/2005 -0400, you wrote:
>>All:
>>
>> OK, this is a stupid question. I'm fixing up the 8800b that I got
>>recently and I removed the fan to perform some work on the power supply.
>>Unfortunately I didn't mark which direction the air blows. Can someone
tell
>>me if it blows inward or outward?
>>
>> Thanks.
>>
>>Rich
>
>Hi Rich,
>
>Both of my 8800s have the fan blowing out.
>
>The general rule is:
>
>If the fan has a filter, then it should blow in.:
>
> By maintaining positive internal pressure, and
> filtering the air that comes in, you keep dust
> from entering the box.
>
>If it does not have a filter, it should blow out:
>
> A fast moving stream of air will carry more dust
> than a slow one. If you blow the fan in, it will
> carry dust into the box which will drop out before
> it exits at slower speed (because of the much larger
> area of all the vents and other openings) - it also
> causes dust buildup to concentrate that certain
> points bacause of sudden changes in airflow (you can
> often see bands of thick dust in boxes with fans
> improperly installed). Going the other way reduces
> the entry speed (same reason) and thus the amount of
> dust that enters - what does get in tends to settle
> out in a more uniform distribution.
>
>Regards,
>Dave
>--
>dave04a (at) Dave Dunfield
>dunfield (dot) Firmware development services & tools: www.dunfield.com
>com Collector of vintage computing equipment:
> http://www.parse.com/~ddunfield/museum/index.html
>
>
>
On Jun 17 2005, 7:47, Cini, Richard wrote:
> Rules-of-thumb like this are great to know. The fan, I'm sure,
was
> installed (like the IMSAI) blowing IN because the inside was caked
with
> dust. So, I made it an exhaust fan (no filter).
>
> As I work on the IMSAI, which has no filter either, I will swap
it
> around, too.
Don't do that. If it's designed to blow in, changing the direction to
blowing out will alter and probably reduce the cooling. Why? Because
turbulent air is lots better at cooling than a laminar flow, and will
reach more parts of the case. You get turbulent air from the "blow"
side of a fan, but laminar flow towards the inlet side. You may also
be directing the airflow away fom some component that previously was
cooled, eg a PSU. Moreover, if you alter the flow direction so that
air is being sucked in through all the other orifices, it will be
entering via the fronts of disk drives etc (well, probably not on this
machine but I'm thinking of the general case). That's the last place
you want the dust. Far better it drops on the motherboard where you
can vacuum it out. Better still, fit a filter.
--
Pete Peter Turnbull
Network Manager
University of York
>> You may want to compare your drive to the documentation on the
>> HP 88780 under bitsavers/pdf/hp/tape
>
> These 9 track SCSI tape drives (HP 88780) were AKA 7979A, 7980A,
7980XC/SX.
> The were OEMed by a LOT of manufacturers, including IBM, Sun, Tandem,
etc.
I've never seen a Tandem that wasn't HV Differential SCSI.
A lot of them have come through BDI.
Sun-labeled ones are what you should watch for.
They all seem to have the 800bpi option, and are SE SCSI.
I have 3 working RK05 drives on my PDP-11/40 and have used them to
successfully read and copy the data from RK05 packs that had not been
spun up since the 1970s and early 1980s, but I guess I'm on the wrong
side of the ocean.
Good luck with recovering the data. I know what it's like to finally recover
data from a pack that has been lying dormant for nearly 30 years. It's
quite an exciting feeling, especially if it's stuff that you or your associates
developed and you had once written it off as "lost forever".
Ashley
-----Original Message-----
From: Johnny Billquist <bqt at Update.UU.SE>
Sent: Jun 17, 2005 8:00 AM
To: cctalk at classiccmp.org, gtoal at gtoal.com
Subject: Re: Is this an RK05? Can anyone read it?
On Fri, 17 Jun 2005 Graham Toal <gtoal at gtoal.com> wrote:
Hi.
> There was once a student project to write a multi-tasking operating
> system for the PDP11. Written at Groeningen University in the
> Netherlands under the supervision of professor Harry Whitfield,
> this O/S had more than a passing resemblance to the classic
> mainframe O/S, EMAS, from Edinburgh.
>
> The O/S was thought to be lost apart from small excerpts that were
> documented in the project report (online at:
> http://history.dcs.ed.ac.uk/archive/scans/guts/ )
>
> but a disk pack has turned up which has a fair chance of containing
> a working binary and sources.
>
> We think this is an RK05 pack for a PDP11:
>
> http://www.gtoal.com/images/rk05.JPG
>
> Can anyone confirm that?
It's definitely an RK05. If it is for a PDP-11 is another issue.
RK05 packs are hard sectored. If you look at the bottom, you'll find a
metal edge with grooves in it. The grooves marks sectors. A PDP-11 RK05
will have 13 grooves. If it's for a PDP-8, it will have 17. I've also seen
packs with 32 (or if it was 33) grooves. Don't know what system that is
for.
The grooves are evenly spaced, except for one, which is two grooves rather
close together, which marks the start of a revolution.
> And is there anyone in the UK who could read the drive? It may be
> in a format that is backwards compatible with one of the DEC O/Ses,
> or it may be unreadable at the FS level, just readable at the
> block level. (Which shouldn't be an insurmountable problem, given
> the scan of the documentation; also a disk image should pop right
> in to one of Bob Supnik's emulators.)
>
> If someone trustworthy in the UK would like to have a go at
> reading this drive, the keeper of the disk pack (in Edinburgh,
> Scotland) will mail it to you. It would have to be someone who
> I recognise from the list or who would be vouched for by a
> list regular. As you can imagine we're a little squirrely
> about sending the only copy to a stranger, especially in view
> of an unfortunate experience we had last year.
>
> This drive probably has not been spun up since 1978 or 79.
>
> If anyone would like to help, please email me at gtoal at gtoal.com
Well, I'm not in England, and you probably don't know me. I probably do
have the ability to read the pack, but it would require some work on my
part. The PDP-11 I have with an RK11 controller is located 80 km from me,
and it don't have any RK05 drives attached today. I have PDP-8 systems at
home, which have RK05 drives. So it would mean getting an RK05 into a car,
drive to where the PDP-11 is, hook things up, and then run.
And I'm in Sweden.
Johnny
Johnny Billquist || "I'm on a bus
|| on a psychedelic trip
email: bqt at update.uu.se || Reading murder books
pdp is alive! || tryin' to stay hip" - B. Idol
