2 Jun
2009
2 Jun
'09
10:58 p.m.
I've got a VAX-11/750 and DEC RK07 that I picked up from a friend a few
months ago, which I need to divest myself of.
Both have some issues; I'm not sure what the issue is with the RK07
(though I do have the service manual for the drive), and the 11/750 has
some sort of issue with its console. I haven't touched either one,
this is what the previous owner has told me.
They're available free for pickup, or I can deliver them within about an
hour's drive of here for some gas money.
The machines are in West Lafayette, IN 47906, USA.
If they aren't gone by Sunday, June 14th, they'll go on ebay.
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
2 Jun
2 Jun
11:16 p.m.
And, they've been claimed.
That was fast.
Pat
On Tuesday 02 June 2009, Patrick Finnegan wrote:
I've got a VAX-11/750 and DEC RK07 that I picked
up from a friend a
few months ago, which I need to divest myself of.
Both have some issues; I'm not sure what the issue is with the RK07
(though I do have the service manual for the drive), and the 11/750
has some sort of issue with its console. I haven't touched either
one, this is what the previous owner has told me.
They're available free for pickup, or I can deliver them within about
an hour's drive of here for some gas money.
The machines are in West Lafayette, IN 47906, USA.
If they aren't gone by Sunday, June 14th, they'll go on ebay.
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
3:52 p.m.
On Thu, Jun 4, 2009 at 3:26 PM, e.stiebler <emu at e-bbes.com> wrote:
Patrick Finnegan wrote:
Indeed. 15 years ago, I was able to save the 11/750 from work, but
could not find room for a pair of RK07s and a pickup-truck-load of
RK07 cartridges. Those were good drives - easy to repair, decent
amount of storage for the day, fast. Just don't get your fingers
behind the ears on the voice coil during a power-down - those heads
snap back *fast*! (when the NiCd pack is good, that is).
Someone just got a fun little system to play with. Hopefully we'll
hear what it's running and how it's loaded before too long.
-ethan
And, they've been claimed.
That was fast.
Yes, I can imagine. I gave mine away, and now I'm missing it ;-) 
4:27 p.m.
On Jun 4, 2009, at 3:52 PM, Ethan Dicks wrote:
Indeed. 15 years ago, I was able to save the 11/750
from work, but
could not find room for a pair of RK07s and a pickup-truck-load of
RK07 cartridges. Those were good drives - easy to repair, decent
amount of storage for the day, fast. Just don't get your fingers
behind the ears on the voice coil during a power-down - those heads
snap back *fast*! (when the NiCd pack is good, that is).
*SLAM!* Yes, I nearly got my finger caught in one of those.
It's a shame you weren't able to grab those RK07s. They're pretty
thin on the ground nowadays. I agree that they're really, really
nice drives.
Someone just got a fun little system to play with.
Hopefully we'll
hear what it's running and how it's loaded before too long.
Did it go to someone here? If not, perhaps that person should be
invited to join.
That said...I've been sorta halfway thinking of starting a VAX-11
"registry" of sorts, as there aren't huge numbers of those machines
left. They're not super-rare, I know, but there seem to be far fewer
of them than, say, Kaypros.
-Dave
--
Dave McGuire
Port Charlotte, FL
5 Jun
5 Jun
5 a.m.
On Thu, 2009-06-04 16:27:14 -0400, Dave McGuire <mcguire at neurotica.com> wrote:
That said...I've been sorta halfway thinking of starting a VAX-11
"registry" of sorts, as there aren't huge numbers of those machines
left. They're not super-rare, I know, but there seem to be far fewer of
them than, say, Kaypros.
Unfortunately, I only have a 6320. But if anybody wants to get rid of
their VAX gear (anything sized from VXT to 9000, maybe with the
exception of the most common 4000/60, /90 and /90A models), I'll give
them a good, new home!
MfG, JBG
--
Jan-Benedict Glaw jbglaw at lug-owl.de +49-172-7608481
Signature of: Wenn ich wach bin, tr?ume ich.
the second :
1:27 p.m.
Date: Thu, 4 Jun 2009 15:52:40 -0400
Subject: Re: For pickup: VAX-11/750 and RK07
From: ethan.dicks at gmail.com
To: cctalk at classiccmp.org
On Thu, Jun 4, 2009 at 3:26 PM, e.stiebler wrote:
Definitely good advice to keep your fingers away from the heads
and carriage near the voice coil! I have a movie clip on my site
showing the loading of the heads on an RK07. Moving in *fast* from the
rest position (far rear) to track 00 and then slowish to the inner
track and then back to track 00. After that the READY light will lit.
The movement from the far rear to the edge of the platter is quite
fast ... But I wanted to see what would happen if you disconnect the
head that reads the servo track ... pity that I do not have a movie
of that, but I sure don't want to repeat that just for a movie.
The heads move from the far rear at full speed all the way to the
inner track and then at that same fast speed back outward.
Having your fingers there would certainly hurt a lot. Now, without
control, just by NiCad pack at brute force, I can imagine that the
movement will be even more deadly for your fingers.
If you have an RK07 drive, open the rear top lid, use a piece of wood
to push down the lock mechanism of the head carriage and carefully
try to pull the heads out of their far rear position. If the NiCads
are still OK, you will need a lot of force the moment the microswitch
clicks. At that point I stopped. I don't know how good the NiCads in
that drive are (still need to check that), but it was impressive.
I guess the RK05 will behave similar with a good NiCad pack.
I have five (!) RK07 drives. I want to keep 3 of them, so sooner or
later two drives will have to go (in The Netherlands).
I plan to connect them all to the RK07 Field Test Box to see in what
shape they are. They should all be OK ...
- Henk.
Patrick Finnegan wrote:
Indeed. 15 years ago, I was able to save the 11/750 from work, but
could not find room for a pair of RK07s and a pickup-truck-load of
RK07 cartridges. Those were good drives - easy to repair, decent
amount of storage for the day, fast. Just don't get your fingers
behind the ears on the voice coil during a power-down - those heads
snap back *fast*! (when the NiCd pack is good, that is).
Someone just got a fun little system to play with. Hopefully we'll
hear what it's running and how it's loaded before too long.
-ethan
And, they've been claimed.
That was fast.
Yes, I can imagine. I gave mine away, and now I'm missing it ;-)
1:46 p.m.
On Fri, Jun 5, 2009 at 1:27 PM, Henk Gooijen <henk.gooijen at hotmail.com> wrote:
I have five (!) RK07 drives. I want to keep 3 of them,
so sooner or
later two drives will have to go (in The Netherlands).
I plan to connect them all to the RK07 Field Test Box to see in what
shape they are. They should all be OK ...
They probably are... in my experience, they are very sturdy
mechanically and electrically.
I was cleaning and prepping for sale a pair of them about 21 years
ago.. one was just fine, but when I flipped the breaker on the second
one, *huge* amounts of thick black smoke poured out of the PSU. I
slapped the breaker off and tipped back the PSU to see what happened -
two of the rectifier diodes (1N4007 or similar) were charred and
perforated. A few minutes with a DVM narrowed down the problem to a
completely-shorted filter cap. It was great that it was held in with
#8 bolts, not solder. The "hard part" of the repair was replacing the
diodes.
Lots of smoke + two $0.07 diodes + one C-battery-sized filter cap ==
working drive!
It was one of the easiest DEC repairs I ever had.
-ethan
6 Jun
6 Jun
1:17 p.m.
I plan to
connect them all to the RK07 Field Test Box to see in what
shape they are. They should all be OK ...
They probably are... in my experience, they are very sturdy
mechanically and electrically.
I was cleaning and prepping for sale a pair of them about 21 years
ago.. one was just fine, but when I flipped the breaker on the second
one, *huge* amounts of thick black smoke poured out of the PSU. I
slapped the breaker off and tipped back the PSU to see what happened -
two of the rectifier diodes (1N4007 or similar) were charred and
perforated. A few minutes with a DVM narrowed down the problem to a
completely-shorted filter cap. It was great that it was held in with
#8 bolts, not solder. The "hard part" of the repair was replacing the
diodes.
Lots of smoke + two $0.07 diodes + one C-battery-sized filter cap ==
working drive!
Excellent...
Reminds me of the time smoke poured out of a 3rd party (Plessey IIRC)
Unibus expanison box. It was clearly coming from the PSU area and I
thought I could see something glowing orange inside. Turns out (after
takign the PSU apart) that a bridge recifier had shorted and the orange
glow was the wires linking that to the transformer -- all the insulation
had burnt off and they were more than red hot. Replaced the rectifier and
thw wires, no problems...
-tony
1:58 p.m.
On 6 Jun 2009 at 18:17, Tony Duell wrote:
Reminds me of the time smoke poured out of a 3rd party
(Plessey IIRC)
Unibus expanison box. It was clearly coming from the PSU area and I
thought I could see something glowing orange inside. Turns out (after
takign the PSU apart) that a bridge recifier had shorted and the
orange glow was the wires linking that to the transformer -- all the
insulation had burnt off and they were more than red hot. Replaced the
rectifier and thw wires, no problems...
That UPS I wrote about a couple of days ago turned out to have a
similar problem that should have resulted in magic smoke, but a
thoughtful engineer saved me from that.
An inspection of the curcuit showed that the UPS will not engage when
powered on unless the batteries (4x12v wet cell lead-acid) are
supplying current. Once energized, the unit will supply power as
long as AC power is present (allows you to change batteries without
interrupting power).
The batteries were flat. A test with an automotive battery
charger/tester showed that all would hold a full charge.
What caused my unit to brick was a shorted 1000uF 100V filter cap in
the charging circuit. But no bulging cans, magic smoke or any other
sign that anything was wrong. An ECO had been added at some time
that included a 20A fuse in the secondary of the inverter
transformer. Said fuse was in a holder tucked away under a nest of
wires attached to the inside front panel with an adhesive cable tie.
The unit kept operating until a thunderstorm caused the power to
glitch momentarily. With no battery power, the unit would not power-
cycle when the line supply recovered. That fuse could have blown
months ago without showing any outward sign.
Once the (blown) fuse was discovered, it was pretty obvious that
something upstream was wrong. A quick check with an ohmmeter turned
up the bad cap.
The charging circuit is pretty crude by modern standards--an LM317K
TO3 regulator on a large (4"x6") heatsink with a 50W zener and a
thermostatic switch. It could probably benefit with some upgrading
to a "smarter" circuit.
This UPS has been in continuous service since 1989.
--Chuck
3:08 p.m.
On 6 Jun 2009 at 18:17, Tony Duell wrote:
Yes, fuses are very useful for protecting things like transformers and
wiring harnesses. On the other hand, expensive power semiconductors are
useful for protecting fuses ;-)
Reminds me of the time smoke poured out of a 3rd
party (Plessey IIRC)
Unibus expanison box. It was clearly coming from the PSU area and I
thought I could see something glowing orange inside. Turns out (after
takign the PSU apart) that a bridge recifier had shorted and the
orange glow was the wires linking that to the transformer -- all the
insulation had burnt off and they were more than red hot. Replaced the
rectifier and thw wires, no problems...
That UPS I wrote about a couple of days ago turned out to have a
similar problem that should have resulted in magic smoke, but a
thoughtful engineer saved me from that. The charging circuit is pretty crude by modern
standards--an LM317K
TO3 regulator on a large (4"x6") heatsink with a 50W zener and a
What's tyhe 50W zener for, given you have a regualtor chip?
thermostatic switch. It could probably benefit with
some upgrading
to a "smarter" circuit.
This UPS has been in continuous service since 1989.
Well, if it's been working for 20 years with no problems, I am not sure any
'upgrade' is going to be that beneficial :-)
-tony
4:32 p.m.
On 6 Jun 2009 at 20:08, Tony Duell wrote:
It's on the output side of the LM317, so I imagine it's intended as
battery protection.
There's also a honking big diode across the output before the 50A
cartridge fuse in the lead going to the batteries. I assume it's to
protect the circuitry in case the batteries are connected with
reversed polarity.
--Chuck
Yes, fuses are very useful for protecting things like
transformers and
wiring harnesses. On the other hand, expensive power semiconductors
are useful for protecting fuses ;-)
A friend who worked as a DEC field engineer used to talk about DEC
being notorious for "transistor protected fuses".
The charging
circuit is pretty crude by modern standards--an LM317K
TO3 regulator on a large (4"x6") heatsink with a 50W zener and a
What's tyhe 50W zener for, given you have a regualtor chip?
3:59 p.m.
On Saturday 06 June 2009, Chuck Guzis wrote:
The charging circuit is pretty crude by modern
standards--an LM317K
TO3 regulator on a large (4"x6") heatsink with a 50W zener and a
thermostatic switch. It could probably benefit with some upgrading
to a "smarter" circuit.
This UPS has been in continuous service since 1989.
There's really only 3 reasons I bother upgrading my UPSes whenever I can
find a newer, cheap to free one:
1) Newer models seem to have a charging circuit that's smart enough not
to overcharge nearly-dead batteries to the point at which they expand
and blow their seals. Cleaning batteries that have done this out of a
UPS runs somewhere from "difficult" to "a complete mess". And,
I've
had to clean this up several times out of UPSes I've received; the only
good thing is that it usually makes the UPS much less expensive to
acquire. :)
2) Higher-efficiency inverters mean more runtime out of the same
batteries, and usually at the same time, a lighter UPS. Considering
how often I seem to move stuff around, lighter is definately a plus.
3) Better monitoring. I really like the amount of information that I
can get out of SNMP on a modern UPS's network card.
That said, if you replace the batteries as recommended (3-5 years) with
good quality batteries, an older UPS will do quite admirably for most
people, and can be more useful for hacking up to do different things
(like mashing three of them into being a 3-phase inverter, which is
somewhere on my project list, to power stuff like my IBM 3420, and
Liebert System/3).
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
4:45 p.m.
On 6 Jun 2009 at 15:59, Patrick Finnegan wrote:
1) Newer models seem to have a charging circuit
that's smart enough
not to overcharge nearly-dead batteries to the point at which they
expand and blow their seals. Cleaning batteries that have done this
out of a UPS runs somewhere from "difficult" to "a complete mess".
And, I've had to clean this up several times out of UPSes I've
received; the only good thing is that it usually makes the UPS much
less expensive to acquire. :)
I think the LM317(mumble-mumble-high-voltage-suffix) is limited to
about 1.5A output current anyway. And the batteries I'm using are
basically garden-tractor batteries, not gel-cells, which seem to have
a rather short (3-4 years) in UPS. I replace the batteries (in their
own box) in mine about every 6 years--and I check the electrolyte
level every 6 monts.
2) Higher-efficiency inverters mean more runtime out
of the same
batteries, and usually at the same time, a lighter UPS. Considering
how often I seem to move stuff around, lighter is definately a plus.
No argument there, except that many cheap inverters deliver only an
approximation to a sinewave output.
3) Better monitoring. I really like the amount of
information that I
can get out of SNMP on a modern UPS's network card.
This one has some sort of RS-232 output, but I haven't the faintest
what it indicates, other than "your power just failed". I've got the
software for it somewhere, but have never run it.
... and can be more useful for hacking up to do different
things (like mashing three of them into being a
3-phase inverter,
which is somewhere on my project list, to power stuff like my IBM
3420, and Liebert System/3).
They also make great sources of big power transformers for linear
power supplies. Some have multiple high-voltage windings, so they
can also serve as isolation transformers.
--Chuck
7 Jun
7 Jun
1:22 p.m.
This one has some sort of RS-232 output, but I
haven't the faintest
what it indicates, other than "your power just failed". I've got the
software for it somewhere, but have never run it.
For older/simpler UPSes, it's quite common for that not to be a real
serial port, but just a collection of status lines (mains failed,
batteries getting low, etc) which can be read over the 'handshake' inputs
of an RS232 port.
And the cable might be strange. It might even have components in it. At
least one manufacturer put optoisolators in the cable (!).
-tony
2:08 p.m.
On 7 Jun 2009 at 18:22, Tony Duell wrote:
For older/simpler UPSes, it's quite common for
that not to be a real
serial port, but just a collection of status lines (mains failed,
batteries getting low, etc) which can be read over the 'handshake'
inputs of an RS232 port.
That's probably the extent of it--there's a DIP switch group that I
imagine dictates what goes to what. But no UARTs or other signs of
intelligence.
--Chuck
6 Jun
6 Jun
2 p.m.
I took it apart and cleaned and dried it. Everything
looked OK, so I fired
up the PSU. It worked. Added the logic boards. Everything seemd to work.
So for a laugh I put in a scratch pack, fully expecting a head crash. No,
the heads loaded with no prolems. And it worked (and works) fine...
Usually, water does no damage IF the equipment is unpowered AND it is
properly dried up before powering
5 Jun
5 Jun
4:08 p.m.
Indeed. 15 years ago, I was able to save the 11/750
from work, but
could not find room for a pair of RK07s and a pickup-truck-load of
I think I'd have takne the drives (and put them on an 11 or something)
and left the VAX. The 11/750 is not a machine I greatly care for....
RK07 cartridges. Those were good drives - easy to
repair, decent
I am not convinced abotu the 'easy to repair'. I've read the printset,
and that servo system is _complicated_. And don't you need some rather
special tools/test gear to fit new heads?
-tony
6 Jun
6 Jun
2:08 p.m.
On Fri, Jun 5, 2009 at 4:08 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I've seen your posting about the 11/750 and I cannot refute them given
your interests and proclivities, but this happened to be the machine I
first learned VMS on, the first machine I wrote a UNIX driver on, and
one that' I'd upgraded internally many times (it shipped with 512K and
I upgraded it myself to 8MB to give it five more years of use as the
company's main machine for all e-mail, software development and sales
activity). This machine and I have a history going back some time, so
I couldn't just leave it behind. The drives weren't stackable (unlike
the RL02s and the RA81s) so they had a large footprint for 28MB each
and I just didn't have a place for them.
I don't know about heads - in a decade of running RK07s daily, we
never had to fiddle with heads - we just kept from crashing our packs.
Our failures were all electronics and easy to access, diagnose, and
repair.
My experience only, of course, YMMV.
-ethan
Indeed. ?15
years ago, I was able to save the 11/750 from work, but
could not find room for a pair of RK07s and a pickup-truck-load of
I think I'd have takne the drives (and put them on an 11 or something)
and left the VAX. The 11/750 is not a machine I greatly care for.... RK07
cartridges. ?Those were good drives - easy to repair, decent
I am not convinced abotu the 'easy to repair'. I've read the printset,
and that servo system is _complicated_. And don't you need some rather
special tools/test gear to fit new heads?
7 Jun
7 Jun
1:08 p.m.
On Fri, Jun 5, 2009 at 4:08 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote:
I've seen your posting about the 11/750 and I cannot refute them given
your interests and proclivities, but this happened to be the machine I
Note that I said that I'd take the drives and leave the VAX. Not that
that that was necessarily the right thing to do, or the thing that you
should have done :-)
Of the VAX 11/7xx machines, the 11/750 is my least favourite, due to the
fact it's stuffed with gate arrays that are, I assume unobtainable now
(and from what I remmeber, when they were avaialble from DEC, they were
ridiculously expensive!) If I had the sapce, I'd love an 11/78x. But I
don't, so I have an 11/730 that I must get round to looking at [1] That
one is 2910s for the data path and rows of unprotected PALs...
[1] I've been spending far too much of my time on HP stuff. Maybe I
should try another manufacturer for a change :-)
Indeed.
=A015 years ago, I was able to save the 11/750 from work, but
could not find room for a pair of RK07s and a pickup-truck-load of
I think I'd have takne the drives (and put them on an 11 or something)
and left the VAX. The 11/750 is not a machine I greatly care for.... first learned VMS on, the first machine I wrote a UNIX
driver on, and
one that' I'd upgraded internally many times (it shipped with 512K and
I upgraded it myself to 8MB to give it five more years of use as the
Ah, that's a darn good reason for wanting to keep it :-). I still have a
soft spot for the machines I fiest wrote device drivers on, for my own
hardware. Namely a TRS-80 Model 3 running LDOS and a CoCo 2 (later a CoCo
3) running OS9.
[...]
RK07 cartridges. =A0Those were good drives - easy to
repair, decent
I am not convinced abotu the 'easy to repair'. I've read the printset,
and that servo system is _complicated_. And don't you need some rather
special tools/test gear to fit new heads?
4 Jun
4 Jun
4:23 p.m.
On Jun 4, 2009, at 3:26 PM, e.stiebler wrote:
I did too, with both an 11/750 and an RK07. The RK07 was never
used on the 11/750, though. I regretted it for years. A few years
ago, though, John Wilson gave me a pair of RK07s (one of which
runs!), and last fall, I picked up an 11/750 from Patrick.
I still owe Patrick something for the 11/750 (as well as some
other stuff, Patrick, we'll get together on that). I am grateful to
both he and John for helping me to recover from my own stupidity. :)
I dearly love this hardware.
-Dave
--
Dave McGuire
Port Charlotte, FL
And,
they've been claimed.
That was fast.
Yes, I can imagine. I gave mine away, and now I'm missing it ;-)
5:44 p.m.
On Thursday 04 June 2009, Dave McGuire wrote:
On Jun 4, 2009, at 3:26 PM, e.stiebler wrote:
I did too, with both an 11/750 and an RK07. The RK07 was never
used on the 11/750, though. I regretted it for years. A few years
ago, though, John Wilson gave me a pair of RK07s (one of which
runs!), and last fall, I picked up an 11/750 from Patrick.
Oddly enough, I'm giving up the 11/750 (the third or fourth that has
gone through my hands), mostly because it's too small, and not nearly
as interesting as my 11/780(s). :)
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
And,
they've been claimed.
That was fast.
Yes, I can imagine. I gave mine away, and now I'm missing it ;-)
10:14 p.m.
On Jun 4, 2009, at 5:44 PM, Patrick Finnegan wrote:
I did too, with both an 11/750 and an RK07. The RK07 was never
used on the 11/750, though. I regretted it for years. A few years
ago, though, John Wilson gave me a pair of RK07s (one of which
runs!), and last fall, I picked up an 11/750 from Patrick.
Oddly enough, I'm giving up the 11/750 (the third or fourth that has
gone through my hands), mostly because it's too small, and not nearly
as interesting as my 11/780(s). :)
ROFL!
--
Dave McGuire
Port Charlotte, FL
And,
they've been claimed.
That was fast.
Yes, I can imagine. I gave mine away, and now I'm missing it ;-)
5519
days inactive
5523
days old
22 comments
9 participants
participants (9)
-
alexandre-listas＠e-secure.com.br -
ard＠p850ug1.demon.co.uk -
cclist＠sydex.com -
emu＠e-bbes.com -
ethan.dicks＠gmail.com -
henk.gooijen＠hotmail.com -
jbglaw＠lug-owl.de -
mcguire＠neurotica.com -
pat＠computer-refuge.org