>From: "vrs" <vrs at msn.com>
>
>> Wow! Those look DAMNED good to me!! :-)
>> Congrats on the effort...
>
>Thanks! I still want to work a little on the air bubbles, and of course try
>to get closer to the DEC colors.
>
>> Once you get the process down, please document the materials and the
>> techniques so that it may be replicated easily.
>
>Will do, though there is a fair bit of mold tweaking, color mixing, etc.
>that I'm not sure how to make a recipe for.
>
>> Once we get the plastic stuff down, they'll be no reason for any
>> classiccmp to remain unrestored...
>
>I can think of a few more parts made of unobtainium (but I'm working on it)
>:-).
>
> Vince
>
>
Hi Vince
Can you get your hands on a vacuum pump. If you pour the
stuff in a vacuum and then release it to air, you shouldn't
have any bubbles. What material are you using for the
plastic. Some of these things can handle a vacuum while
others can't. Even using a hand pump made from a bicycle
pump can do wonders at removing bubbles.
How about a list of the materials you use for molds,
colors and plastic?
Dwight
>From: "Vince Slyngstad" <v.slyngstad at verizon.net>
>
>I put up some pictures of the switch handles I have cast so far. (It will
>be clear why I think they're not ready for prime time.)
>
>http://so-much-stuff.com/pdp8/sw-handles.html
>
> Vince
>
>
Hi
This is great. What are you using to make the molds?
Dwight
>From: "Eric Smith" <eric at brouhaha.com>
>
>Ashley wrote:
>> What kind of scope would I need and how much does one cost?
>
>Assuming that you want something good but cheap, your best bet is
>probably to try to find an old Tek 465. It's a good, solid two-channel
>100 MHz scope. ISTR that they show up on eBay frequently, but as
>with anything on eBay, there's no telling what condition it would
>really be in.
>
---snip---
Hi
The only issue I've seen with the 465's is that if the
sweep frequency switch is broken ( a common failure on these ),
this switch is unobtainium.
It is good to have more than two chanels of input. It is
also useful to have the delayed sweep. Other than that,
I like others would recommend a 100MHz as a minimum. Stay
away from the 20-30 MHz scopes that are often used for TV
repair.
You need to get scope probes. These should be 10X probes
for doing digital work.
Even though Leader doesn't have a good reputation, I've
been using one of their high end scopes that has 4 channels,
150 MHz bandwidth and A/B delayed sweep. It has been a good
scope.
I still like the Tectronix better but when I bought mine
( for $75 ) the Tec's were out of my price range.
One thing that I've always wanted to build but have just
never had the time is a trigger qualifier. What this is
is a large input and gate. It might also have some sequencing
as well. Now days, this could be done with some of the
FPGA that you reload on each powerup. The idea is that many
things that you want to see in a computer need to be qualified
by a number of signal and may even require some sequencing
to make sure your looking at the right thing. Most logic
analysers do this but they rarely have good sequencing
control. This is their main weakness.
With a reprogrammable FPGA, one can write the formulas
and the state sequencing to most any level of complexity.
Of course, one can actually buy a logic analyser but
like I said, they usually have poor sequencial controls
and the display is a little too far removed from the
real signals for me. I like to see the real levels that
only a scope can provide.
Dwight
I recently purchased an MDS 800 without a disk drive. It does have a controller and cable to the backplane for a disk drive. Do you have a schematic for the PCB and a wiring diagram of the PCB to backplane cable. I have some old SA801 drives and a power supply that I could use.
Bob
rsnats at bellsouth.net
Hi,
I built one of the Maplin (a UK kits and components firm) Z80A development
kits back in the early 90's, along with the add-on HEX keypad and 7 segment
displays, and used it for a while. I've just re-discovered it, and would
like to get it going again, but I need a copy of the monitor ROM, if anyone
has it.
I would also like the serial interface and PC assembler software that was
supplied as a third kit (with a different/replacement) monitor ROM, if
anyone has one to spare.
I do still have copies of the original circuits and articles for all three
kits (Z80 board, Keypad/display board, and serial board), and will post them
on my site if anyone is interested.
Thanks
Jim.
Please see our website the " Vintage Communication Pages" at WWW.G1JBG.CO.UK
Would someone happen to have a 1970s-era Signetics TTL handbook in which they could look up some details about the N8266?
I know that it is a quad 2-input multiplexor/selector and I know what the pinout is.
The questions are:
- what is the specific logic functioning of the 2 control inputs?
- is there any inversion in the data path(s)?
>From the cross-references I have the 8266 doesn't seem to have made the transition to a 7400 series standard, probably because it's functioning is a little weird.
They are used in a Wang 520 calculator with the control lines operated in two different manners. While the intent of the circuitry would seem apparent, the two uses of the control lines are somewhat idiosyncratic to each other.
(FWIW: the 520 is circa 1972, TTL logic, micro-program architecture, core rope micro-program store.)
Hey list,
I've recently obtained some AT&T 3B2's, and am diving right in. They
supposedly have been recently working, so I thought it would be an
interesting foray into getting them setup, running, learning about old
UNIX, etc.
Anyhoo, to my dismay most of the ftp sites that had working 3B2
programs are down, moved, or otherwise gone. One of these was a
repository of Owens-Laing publications' "3b Journal" having to do with
3B1's and 2's.
Does anyone have (a) copy(ies) of this or any similar material?
Thanks,
-dhbarr.
I'm looking for a program for a client that I thought I had but after
looking I'm now not so sure.
It's called Apple World by Paul Lutus circa 1980. It was a CAD-type
program that had 3D line drawing.
Does anyone have it? An original would be preferable, but even a copy at
this point would be useful.
This is a bounty so it's worth some bucks. Please contact me off-line.
Thanks!
--
Sellam Ismail Vintage Computer Festival
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Anyone know what the Western Digital WD1935-PL is? I couldn't find a
description with Google nor does it show up in my June 1984 WD Storage
Management Products Handbook. It is in an unknown piece of gear that
could be an older ham radio TNC made by Applied Ditital Technology.
>From: "Jay West" <jwest at classiccmp.org>
>
>I need to replace the battery in an item I have. It's the quartersized/style
>one. The way it is attached to the board, is via a clip arrangement that
>you'd swear makes the battery removable. However, it is in fact soldered or
>spot welded into the clip somehow. As a result, I'd rather not just cut the
>clip arms to replace the battery as I'd have trouble getting the new one in.
>
>The only possibility I see is unsoldering the clip from the battery, but it
>strikes me as a rather bad idea to put a soldering iron to a battery.
>Suggestions?
>
>Jay West
Hi Jay
If the clip is attached to the cell, it is most likely
spot welded. It is difficult to actually solder directly
to a cell without damaging the seal on the cell.
I usually causes excess pressure in the cell bursting
the seal. If you can't find a cell with solder tabs,
take it to one of those battery stores that are around.
We have a chain out here called Batteries Plus. You may
have to talk nice to the fellow their to get them to
do the job for you but they have the spot welder to
do the job.
Dwight
