On 11/23/2014 02:53 PM, John Foust wrote:
> At 09:28 PM 11/21/2014, William Donzelli wrote:
>> The NASA model 67 reportedly had 66 ounces of gold in the CPU. Even an
>> early model 30 could have 8 or 9.
> How could a CPU have four-and-a-half pounds of gold?
>
>
I'm VERY skeptical of this one! First, I know IBM went to
great lengths at some time in
the early 60's to figure out how to make reliable computers
with a LOT less gold than
the traditional wisdom required. As far as I know, all
360's had a LOT less gold in
them than similar-sized machines from other makers at the
same time.
On the other hand, a lot of gear from the mid-60's actually
used gold as the etch
resist on the circuit boards. I have some examples of
that. The traces of the
boards are totally plated with gold!
Jon
Hello,
I recently recused a TRS-80 Model 16.
It's in beautiful condition and appears to be fully functional.
I received some 8" SS,DD 128/F floppies with it, but unfortunately none of
them appear to have anything on them (that I can tell) - receive "BOOT
ERROR RS" on this system.
What are my options? This is my first TRS-80 model II/8" floppy-based
hardware.
I'm located in central Wisconsin.
Thanks!
-Bill
Hi all,
Now that I've got some BA23s I've been busy building up a few Q-bus
systems. I've got one KA650 based system with a good, booting RD54 and one
KA655 based system with a good, booting Maxtor 340 MB ESDI drive (via a
Sigma controller). Points to Maxtor for quality, I guess!
As fun as it is to boot the vintage VMS 5.x releases on these drives and
fool around, I'd like to get OpenVMS 7.2 or 7.3 installed at least on my
KA655.
While I'm saving up my pennies for a Q-bus SCSI card, does anyone know if
it's possible to do both a net-boot and a fresh VMS installation given an
existing VAXcluster where I do have a SCSI CD-ROM hooked up to one of the
machines?
I don't just want to boot it as a satellite node, I just want to use the
net-boot to bootstrap an installation since I don't have a local CD-ROM on
that machine to boot from.
If I can get it booted as a satellite maybe there's something "unsupported"
I can do to perform a network installation?
If not I guess I'll just play with 5.x until I can get a SCSI card on hand.
Thanks!
Sean
Need some help on this one.. trying to repair the built-in CRT in an
Osborne Vixen portable. There's some complexity here, so I'll do my best to
be succinct.
The unit presented with a vertical line down the screen, and very low
voltages on the scan-derived power supplies - the 50V in particular was
doing about 18-20V
Removed / tested the horiz. opt. transistor (HOT). Neither open nor
shorted, but beta measures ~12. Replaced the HOT and scoped the B & C
circuits - base drive was +much+ higher (like 10X) level than the output at
the collector. So again pulled the HOT and swapped in the only thing I had
that +seemed+ it might work:
RCA SK9118 (375) - Pt 25W / Vcbo 200V / Vceo 150V / Vebo 6V / Hfe 150 (typ.)
Bingo! Display is now bright & crisp, looks great.. but.. the sub. HOT is
running way, way hot. Rose to 170F in 2-3 min, and was steadily climbing.
And that's in free air, not sealed up in the case.
50V supply came up to 42V.. better, still seems too low. So I think you can
see my conundrum, here.. Is the +original+ HOT actually OK, and I'm only
masking another problem in the circuit by installing a new part with 10X
the gain? Why is the new part running so dang hot - and if the orig. is in
fact bad, what killed it, anyway?
To make things worse, I can't find +any+ service data or parts list for the
display; all I have is a schematic. Nor can I find a datasheet for the
original HOT - so I can't tell if it's in or out-of-spec. It's marked "SGS
1070 / 8309". I +think+ the 8309 is for March 1983 but who knows.
Any ideas on this one, folks? =)
I?m getting rid of my HP 16500C logic analyzer. It?s got the 16550A and 16517A modules. The former has 96 data channels and 6 clock/data channels, all at 100MHz; the latter provides 16 channels @ up to 4GHz.
It comes with all the pods/probes and many connectors, as well as the manuals and training materials. It passes all self-tests.
I?m in Vancouver, BC. The LA is probably too big to ship economically, but if someone in the BC lower mainland or Washington state is interested, let me know.
I?ve got it up on Craigslist for a firm $300 (http://vancouver.craigslist.ca/nvn/ele/4775079685.html <http://vancouver.craigslist.ca/nvn/ele/4775079685.html>), but list members can make me an offer.
Thanks,
Rob Ferguson
> How could a CPU have four-and-a-half pounds of gold?
First, 66 oz. of gold really is not all that much metal. If you ever
have the chance to hold a pound of gold, take it - it is impressive
how a little lump can be so heavy.
Second, the 2075 was really freakin' big.
--
Will
At 09:28 PM 11/21/2014, William Donzelli wrote:
>The NASA model 67 reportedly had 66 ounces of gold in the CPU. Even an
>early model 30 could have 8 or 9.
How could a CPU have four-and-a-half pounds of gold?
- John
> From: Johnny Billquist
> The RX02 is not a standard double density floppy. It is a single
> density format floppy with a double density encoding for the data area
> of each sector. ..
> I have double density IBM floppies at home, and believe me, I have
> tried using them in RX01 and RX02 drives.
Something I'm mildly curious about, all, knowing very little of the very-low
level recording techniques used in single-density, RX02, and 'standard'
double-density 8" floppies:
The RX02 documentation indicates that the encoding scheme used in the
double-density data portion of the sector is 'Modified Miller Code'. (Miller
Code I get - it's either 0 or 1 flux reversals per bit time, which is half the
maximum flux reversal rate used in the single-density FM encoding - but the
Modified Miller is beyond me; it's not explained very clearly, and I don't see
any value to forcing my aging neurons to work it out! :-)
So, my question: is either of those (Miller and Modified Miller) the same
recording scheme used in standard double-density, or do those use something
else again?
Noel
I am still unpacking after the move....
Anyway, I came across my HP2100A minicomputer, so I took a long look at it (seriously, I must have
spent a couple of hours pulling boards, etc). Some day I would like to get it running again.
I have the standard 8 CPU boards, and the 12895 DMA board. I almost have 32K of core. What I
mean by that is that I have all the boards for 32K words of core. I am missing one of the top
connectors between a core board and the address driver next to it.
I have a few I/O cards in the machine :
12531-60022 Buffered TTY Reg (2 off) looks to be current loop and RS232 serial
12551-6002 Relay Out Reg
12592-6001 +8 but Dup Reg (8 bit parallel for paper tape punch/reader?)
12554-60023 +16 bit Dup Reg (16 bit parallel?)
12566-60021 +True In/Out (another 16 bit parallel?)
13210-60004/6 Disc Interface 1/2 (7900 interface, 2 boards)
12539-60001 Time Base Gen (Heartbeat interrupt ?)
12590-6001 Plotter (I can find nothing about this board on the obvious sites).
Anyway, I have downloaded the appropriate manuals, but have some questions...
What is Current Transfer Logic, the machine seems to be full of such ICs? Any data sheets,
etc out there?
I assume there's no chance of me finding a top connector for the memory system. Am I right that the
only difference between the 2 flavours is the spacing of the edge connectors on the PCB? Due to the
fact that the connector plugs into the core plane daughterboard, which is fitted on the component side
of the sense/inhibit board, so the spacing between the edge plugs changes depending on whether the
core is to the left or to the right of the address driver. Both top connectors seem to be just pin-pin
wired on the PCB, but the manuals don't really mention them.
There is a tab on my A2 board telling me I have the floating point microcode and indeed the
6 ROMs are fitted (in sockets) near the standard microcode ROMs. Was there ever a published
source listing of this? It would be interesting...
Any information on that 'Plotter' board?
One major problem concerns the power switch. I don't have the key, and it's currently in the
'panel lock' position. Now, I can trivially jumper the switch to enable the panel but I would
rather not.
I have taken the switch assembly apart (there is an exploded diagram in the IPB manual) and
it seems to use a standard Ace 7 pin tubular lock.
Were all 2100A's keyed alike (like all DEC machines were)? If so, does anyone have the key
cutting data?
If not, I wonder if I could get a replacement lock and key? Or take the existing lock apart (looks
to be one pin to drill out to get it apart, at least the IBM 5170 lock comes apart like that) and
either get a key cut to suit the existing pinning, or re-pin it.
With the configuration I have (assume I can get 32K words of core, and have the I/O cards
I listed) what can I run on it?
-tony
