So after looking at the mess the mice had made of my third RL02 drive I
decided it would probably be better to pull the heads and put them in my
second drive (the one with the bad top head and plugged filter).
Getting heads out was simple, and I decided to put them side to side
with the heads in drive 2. The following images show some interesting
details.
https://i.imgur.com/tcmkUmO.jpg
Note that O is original (the heads from drive 2) and the top heads are
>from drive 3.
First, the heads on the third drive were in pretty good shape and looked
clean. Under the loupe though I could see some fragments of gunk that
needed to be removed. More importantly I did a side view comparison
between the bad top head in #2 and the top head in #3:
https://i.imgur.com/D6HOxND.jpg
This was a really tough picture to take, and you have to zoom in on the
heads in the upper right. But what you can clearly see here is that the
better head from #3 (left one) is pretty much rectangle shaped while the
crashing head from #2 (right one) is shaped like a wedge, with the top
part being narrower than the bottom.
https://i.imgur.com/fEGuOFE.jpg
And of course the filter removed from #2. Note the silicon sludge, I
think this is 100% blocked (and was why the drive made a lot of air/wind
noises when spun up, the fan was cavitating)
This sums it up: I think what happened is the unit was run in a very
dirty environment, the absolute air filter plugged up, and the heads
don't fly as well without that blast of clean air coming in. So they
dragged on the disk, and the ceramic rubbed off (and onto the packs)
which led to the eventual disk damage.
Moral: Change filters. I cleaned up the #3 heads, put the heads from #3
into unit #2, put the air filter from #3 into #2, and fired it up with
the test pack. Goes to ready no problem, will do a full dir/bad with
RT11 later this afternoon to see if I still have two errors on the pack.
It is interesting to note that the bottom head from drive 2 didn't look
too bad, and did not pick up any dirt/oxide from the disk after I
replaced the filter. It was probably flying very close to the platter
but had just enough airflow to make it fly. Still, I'll put it in the
spares pile and think about it for awhile...
Otherwise, back in business. I'll be checking the filter on #1 just to
be on the safe side. It was my RL02 drive from 30 years ago and was not
one of the Solarex ones. Then I'll put fixing this third RL02 on the
calendar (will need new wiring, long ribbon cable, filter, heads, and a
massive clean-up inside), and start working on restoring my darn RSX11M
4.2 disk packs...
I have a POST error on my VAXmate, which I think is related to the hard
disk. I get error codes 81 or 82 depending on whether my MFM emulator is
running or not. I suspect the hard disk controller itself may be faulty,
because I don't see much activity on the MFM emulator itself (it is the
David Gesswein one).
>From the table of contents in Volume 1 of the Technical Reference Manual it
looks like the error codes might be in Volume 2. Only Volume 1 appears to be
available online, does anyone have Volume 2, ideally scanned, or failing
that, who can tell me what those codes mean?
Thanks
Rob
It is called The History of the Personal Computer part 2
He goes to the Xerox building to find the first graphic interface. He walks around and then stops an puts his hand on a Dioblo 30 hard disk drive.
I think he might have missed something.
Dwight
So I got the third RL02 out of the shed this afternoon and after
cleaning the outside I brought it in to disassemble and check out. Being
in an outdoor shed for 15 years is not good for technology, I could see
debris behind the front panel and just knew that mice had gotten into
the unit. The question is how far...
Taking it apart gave me some clues. On the positive side there was no
infestations or dirt/debris/anything past the absolute air filter. As a
bonus, the filter was very clean and there was no debris past the motor
air impeller. This is good, and it gives me a clean air filter with
which to test the other drive to see if the heads will fly (my other
drive had a 100% clogged filter. I need to take some pics)
Bad news is I can see mouse debris down the four tubes on the intake. It
looks like they made a little house under the power supply, which is
where the intake is to the high pressure air system. So I think I'm
going to be pulling the whole AC/DC power supply out and do a major
cleaning.... Hopefully they did not chew the wires.
Never dull.
Trying to figure out a fair value for the following:
Altair 8800b with two Altair floppy drives. System is clean but hasn't
been turned on since the 70s. No software or manuals available. Contains
the follow boards:
1 CPU
2 Floppy disk controller
3 MITS 16k dynamic memory boards (48k ram total)
1 MITS 8800 Disk BD1 Rev 0 x4
1 SIO board with 2 serial ports
1 MITS 8800 PMC Rev01 2k Prom Board
Can reply off list.
Thanks.
David
https://www.team6502.org/
This was on the Team 6502 facebook page
====================================================================
I just received an email from Bill Mensch that Chuck Peddle has died.
He died on December 15. Chuck Peddle was one of the team of eight
Motorola employees and engineers who worked on the 6800 microprocessor
and left the company for MOS Technology in 1974 along with Harry
Bawcom, Wil Mathys, Rod Orgill, Ray Hirt, Mike Janes, Terry Holdt, and
Bill Mensch.
Peddle considered the $300 price point of the 6800 a disadvantage, and
urged Motorola management to pursue a more affordable microprocessor
that could be used in a wider array of applications. When they
refused, Peddle convinced seven other Motorola employees, including my
father Terry Holdt, to pack up their homes and move across the country
to begin work on what would become the 6502 microprocessor at MOS
Technology, a wafer-fab company in Valley Forge, PA founded by a
former colleague of his from General Electric, John Paivinen. After
Commodore Business Machines purchased MOS Technology in 1976, Peddle
oversaw the creation of the Commodore PET computer, the predecessor of
the Commodore 64, the best-selling personal computer of all time.
While curating the information for the team6502.org website, one of my
favorite anecdotes comes from MOS Technology employee, Frank Slattery,
who wrote:
"What a great bunch of guys the Motorola eight were. I was the manager
of the layout people and it was my duty to make sure that the Motorola
eight had every opportunity to do their design work with no problems.
I was standing next to Chuck Peddle when he said to Jack Tramiel, the
CEO of Commodore Business Machines, 'With this chip we can build a
personal computer.' It was the first time I ever heard the words,
'Personal Computer.'"
The rest, as they say, is history...
Chuck was one of the giants of the personal computing industry. Now he
belongs to the ages.
Hi All,
I have a copy of this Intel book, 8048 Family Applications Handbook, January 1980. Does anyone know if scans of this book are online anywhere? I did a quick Google search and didn't find this particular book. If it isn't available anywhere I would like to get it scanned and posted somewhere (bitsavers?), but the only way I have to do a decent scan is destructive.
A picture of the cover is here: http://wrcooke.net/DSC01633.JPG
Thanks,
Will
"A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away." -- Antoine de Saint-Exupery
"The names of global variables should start with // " -- https://isocpp.org
I wonder if there is any interest here...
-----Original Message-----
From: greenkeys-bounces at mailman.qth.net <greenkeys-bounces at mailman.qth.net> On Behalf Of John Lawson
Sent: 10 December 2019 17:41
To: greenkeys at mailman.qth.net
Subject: [GreenKeys] DURA Selectric ASR terminals free
Greetings List!
I have a couple of "DURA" Selectric ASR terminals. I also have some limited documentation on them. Neither of them work as far as I know. I tried to run the one in the pic when I first got it, but it's jammed - so on the shelf it went.
They appear to be an 8-level code, dunno if ASCII, EBCDIC, or what.
These are joining the ever-expanding list of "Projects Never to be Completed", so if anyone is interested, lemme know.
They are free, you pay shipping, they are about 50 pounds each and will require some thoughtful packing.
Local pickup is happily offered, and I could possibly be bribed into delivering them within a day's drive of Carson City (weather permitting).
Cheers
John KB6SCO
Carson City
So one of my RL02 drives (bought on Ebay years ago) is eating RL02
packs. Makes tings, then the disks have errors in my other RL02 drive.
Took a bit to figure out which drive was eating what, but I'm 100%
certain it's this newer drive.
So pulled the heads. The top one had significant gunk on it, the bottom
one a bit. Pics below.
Top: https://i.imgur.com/FELhF9X.jpg
Bottom: https://i.imgur.com/Tmsf5Nd.jpg
With alcohol and lintless swabs I managed to clean both of the heads up.
Top: https://i.imgur.com/gmACM4R.jpg
Bottom: https://i.imgur.com/SfZQV5F.jpg
Then put them back in the drive and mounted a scratch pack. With finger
on the load/run I let the drive spin up and when I heard tinging I
immediately spun down. Hopefully I didn't trash my scratch pack.
Top head has gunk, bottom one had a few flecks, but looks pretty ok.
Top: https://i.imgur.com/EAvgmuH.jpg
Bottom: (picture didn't upload)
Obviously the head is crashing, any idea why and if it's worth replacing
the head or should I put this drive out for parts? Yes I cleaned the
RL02 pack before putting it in.
Never dull.
CZ
Hi - I am looking for some help.
I have had a PDP 8e with RK05 drives that has run pretty reliably for many
years, but after moving it a strange symptom has come up, preventing it
>from operating correctly. I am hoping someone can advise.
Here is an example
1. Power up drives and PDP 8e
2. Load OS/8
3. Load ADVENT
4. Program loads, asks if I want instructions. I can enter Y or N and the
system responds. The familiar scrolling light pattern appears on the front
panel to indicate awaiting input
5. As soon as I attempt an action such as "S" (with no quotes) the front
panel freezes and I have to CTRL+C to exit ADVENT, dumping me to the dot
prompt.
Similar issue when running the MUSIC.SV program. I can load the program and
get up to the point of entering a song, but when I enter a song name the
system freezes on the first note.
BASIC works fine however. Which tells me that I have a CPU problem, not a
RAM problem but this is just my hunch.
Any ideas how to diagnose this? Running MAINDEC programs is always
frustrating. I am attempting to load the main DECX8 SYSTEM EXERCISER to see
if there are any clues from this as to the cause of the freezing system.
.
https://www.pdp8online.com/os/os8/os8_cmd.shtml#DECX8
Thanks
Bill
