>> >How can the transformer possibly work if the primary is only connected
to
>> one
>> >HT line? What is the other side of the primary connected to? Where's
the
>> >return path?
>>
>> Earth
>
>I had an electronics tech that worked for me a number of years, and we were
>working on some control circuits that had only one wire between two panels.
>In answering the question as to how the path was completed, his answer (I
>hope tongue-in-cheek) was through the air. I am assuming here that "Earth"
>was also said tongue-in-cheek!
>
It is the actual way they do it here. See my prior post from looking at the
pole feed.
Dan
I'd kick in ten buck or so for a picture of the bonfire :)
>
> Especially if its not limited to 10 year old stuff. I have all these
> Microsoft manuals and CD's for learning about Microsoft NT 4.0
> (mainly administration stuff)... What i'm gonna do with 8-10 sets
> of this stuff is puzzing me to no end.
>
> -Lawrence LeMay
>
>
>How can the transformer possibly work if the primary is only connected to
one
>HT line? What is the other side of the primary connected to? Where's the
>return path?
Earth
In one of the HP 21MXE machines I received recently, there is a Versatec
printer interface. I have no need for it at all. It consists of about 6 or 8
interface cards, plus a rackmount box. From what I can tell, it was used to
hook up a versatec plotter. It also *APPEARS* to have a parallel interface
on the box, but I don't know any particulars, this may not be correct.
If someone has a real use for it, they're welcome to have it for shipping
costs. However, if no one claims it, I will likely strip off the front panel
switches on the rackmount box (which are the authentic style for my
Nicolet-80 which has some non-authentic front panel switches installed by
the last user) and pitch the rest.
If interested, just email me for particulars.
Jay West
>"Daniel T. Burrows" <danburrows(a)mindspring.com> wrote:
>> Close but not quite right. For single phase installations the power
company
>> supplies 2 hots and neutral. This is a center tapped secondary and the
>> neutral is earthed at the service entrance.
>
>No, for split-phase, the power company does not "supply" a neutral from the
>distribution system. The neutral is *only* tied to the center tap of the
>secondary and to ground. It is not tied to anything on the primary side of
>the transformer; that would be bad.
That is what I was trying to decsribe above.
>> The primary of this transformer
>> is fed from only 1 high voltage phase.
>
>I don't believe this; it doesn't match the descriptions I've read
elsewhere.
>I've always seen it shown in diagrams with the primary connected across two
>phases of the three-phase. Otherwise you need a high-current return path
>somewhere else.
Take a close look at rural areas and there is only 1 High voltage line
present.
It is fed to the HT input of all the pole transformers.
>To even the loading of the phases, the transformers for split-phase service
>have their primaries distributed between the three possible combinations of
>the three phases.
When there are 3 phases available that sometimes is the case. Look closely
at the pole transformers and in most cases when there are 2 or more
transformers mounted on 1 pole there is only 1 HT input to each transformer.
If it were between phases there would be 2 HT inputs.
Dan
At 09:21 PM 4/25/99 -0700, you wrote:
>At 09:43 PM 4/25/99 -0600, you wrote:
>>My original post may have been misleading. It just says "Macintosh" on the
>>back of the case. I'm assuming that it's a 128K Mac because: ...
>>
>>How can I check the memory capacity, to see if it's a 128K or a 512K Fat
>>Mac? I'm not that familiar with Macs.
>
>Boot it up, drop down the left hand (I think) menu and select 'About
>Finder'. This should indicate the memory in the system.
>
>-jim
>
>---
>jimw(a)computergarage.org
>The Computer Garage - http://www.computergarage.org
>Computer Garage Fax - (503) 646-0174
>
When I choose "About the Finder ...", I get
"The Macintosh Finder Version 1.0 (18 Jan 84)
@ 1984 Apple Computer"
No mention of memory size. But I would guess that it doesn't mention the
memory size because no size other than 128K was contemplated; i.e. this is
an original Mac. Any other way to check? BTW, were the "Programmer's
switches" (Interrupt and Reset) de-emphasized after the original Mac? My
Mac Plus has the same microswitches inside the case, but I had never heard
of them before.
This system is a bit of a puzzle. As I understand it, a single drive
original Mac was almost unusable, due to lack of RAM and the need for
frequent disk swaps. So I would expect mint condition. However, this system
(Mac, mouse, KB, Imagewriter printer) shows some signs of wear, even though
it was never upgraded to 512K, and there was no second drive with the system.
Regards,
Mark
>> > CKK FA <xy> 1 11/44 Diagnostic ROM*
>> >My second problem is the first test, I can't find a KKFA*.* test. Is there
>> >another test I can run on the diagnostic ROM?
>>
>> The diagnostic ROM *is* the test :-). This is the "big" bipolar
>> PROM located near the boot PROM's. And the test is executed at startup.
>OK, I'll buy that, BUT why was there a Diagnostic for the Diagnostic ROM at
>one point? It does seem rather redundant though.
I think you're taking the table too literally: the Diagnostic ROM *is*
the Diagnostic ROM test :-). Generically, it's a dirt-simple memory
test which also gives the CPU a bit of a exercise (simple bit manipulation
and looping) in the process. At least some of the Diagnostic ROM's also
do a checksum on themselves (this is actually a requirement for firmware
in some European countries) but I don't know if the 11/44's ROM does this.
>> >CKKKAC0 11-44 KK11B CACHE
>> >
>> >RMI REGISTER (G5179) NOT USED-SKIP HI ORDER BIT ADDRESS TEST
>>
>> The G5179 is the PDP-11/44 Remote Memory Interface (an extremely
>> rare option). You don't have it :-).
>Ah, good, this was the most disturbing of the messages I got.
*Generally*, G-series modules referred to by XXDP+ are modules
with special diagnostic purposes. These G-modules are often simulators or
exercisers, and in many cases were not often found outside of
the manufacturing and repair facilities. Other G-series modules
are the components of low-level formatters and dedicated hardware
test jigs. Many of these modules, according to the hardware indices
I have at hand, were custom-wrapped boards produced in extremely small
(sometimes only 1 or 2) quantities, yet they still have G-numbers.
>Now I've just got to pour through the doc's for the peripherals so I can
>figure out what tests to run on them.
For at least your RL11 and RL02's:
ZRLG?? Controller Test #1
ZRLH?? Controller Test #2
ZRLI?? Drive Test #1
ZRLJ?? Drive Test #2
ZRLK?? Performance Exerciser
ZRLL?? Drive Compatiblity Test
ZRLM?? Bad Sector File Utility
Running the drive tests or performance exerciser with multiple drives
at the same time produces an impressive light show as all the unit lights
blink in both regular and random patterns!
--
Tim Shoppa Email: shoppa(a)trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
>My single biggest problem seems to be stopping a diagnostic once I've
>started it. So far I've been resorting to stopping the CPU and rebooting,
>but one would think that there must be a better way, and that I've missed
>it.
You don't have to reboot; you can often just halt the CPU and start
up XXDP+ again at the restart address (this is given at boot time as
a message on the console.) Some diagnostics (especially the really
extensive memory diagnostics) wipe out the XXDP+ monitor and you do,
indeed, have to reboot.
> CKK FA <xy> 1 11/44 Diagnostic ROM*
>My second problem is the first test, I can't find a KKFA*.* test. Is there
>another test I can run on the diagnostic ROM?
The diagnostic ROM *is* the test :-). This is the "big" bipolar
PROM located near the boot PROM's. And the test is executed at startup.
#3 is #3, but I think this is proper behavior
CKKABD0 11/44 TRAPS
NO FLOATING POINT OPTION PRESENT
NO CIS OPTION PRESENT
CONSOLE
17777707 023252
>>>
>#5 may or may not be a problem with the cache (real problem is my not
>knowing how to interpret it).
>
>CKKKAC0 11-44 KK11B CACHE
>
>RMI REGISTER (G5179) NOT USED-SKIP HI ORDER BIT ADDRESS TEST
The G5179 is the PDP-11/44 Remote Memory Interface (an extremely
rare option). You don't have it :-).
>UNIBUS EXERCISER NOT USED-DMA TESTS NOT PERFORMED
There was also an optional Unibus exerciser that could be installed
instead of the normal terminator. These aren't all that rare - they're
very commonly found inside 11/750's.
--
Tim Shoppa Email: shoppa(a)trailing-edge.com
Trailing Edge Technology WWW: http://www.trailing-edge.com/
7328 Bradley Blvd Voice: 301-767-5917
Bethesda, MD, USA 20817 Fax: 301-767-5927
>> > Take a close look at rural areas and there is only 1 High voltage line
>> > present.
>> > It is fed to the HT input of all the pole transformers.
>
>Same thing is done in rural areas in Oz. They are called SWR lines, which
>is TLA for Single Wire Run AFAIK.
>Not sure of the voltage, but I think it's around 8kv. (240v to
subscribers)
>They are somewhat unpopular, and are prone to surges and sags etc.
>Given the nature of the return path, (ground) and the way it would be
>affected by weather etc, this is not surprising.
I would think it would have a lot more surges and sags than it does. I
guess they manage to keep the HT runs short enough however. I have several
1 to 3 KVA UPS's here and rarely (except during storms) do they kick in.
Boy does it get noisy then with all their alarm beepers going.:) Can't wait
to move them out once I make room (and get batteries for) the 10 KVA online
UPS I picked up.
The HT lines I am on are around 14.5KV. The typical distribution lines I
have found vary from12KV to 14.5 in the different areas I have lived.
Currently in North Carolina.
Dan
Ok, I've finally dusted off this Motorola box I got the other day, it has
a MVME-101 CPU Card, A MVME225-2 Memory card and a MVME 319 Controller.
It runs OS/9 v2.1, it appears to have been used for some kind of robotics
application, but all the other cards have been removed. Does anyone have
more info on this box?
Cheers
Karl
------------------------------------------------------------------------------
Karl Maftoum
Computer Engineering student at the University of Canberra, Australia
Email: k.maftoum(a)student.canberra.edu.au
