> From: Lyle Bickley
> we tested each capacitor for capacitance and ESR
> ...
> Each power supply had to meet it's specifications .. (every test was
> logged and documented).
> ...
> Every year we do a complete DEC specified preventative maintenance on
> the PDP-1 which includes testing every power supply for voltage,
> stability and ripple.
When you tested the caps, did you all write down all the results? (I see you
logged the power supply results, so I'm guessing you all likely did for the
caps too, but you didn't say explicitly.) You all haven't by any chance gone
back and re-measured any of those caps, have you? (Again, standard PM likely
doesn't include measuring individual components - although if you're not
seeing any drift in the results, that's likely a sign that the components
aren't 'evolving'.)
If so, that would be really informative data about the longevity of these
particular electrolytics.
I say "these particular" because I'm starting to suspect that different
electrolytics behave differently - likely because of fine details of internal
construction, chemistry, etc. And it might even be details that the
manufacturers were not aware of.
I am reminded of a story (which I don't have time to chase down, to make sure
I have the details right) from the SR-71, or maybe it was some NASA gear.
Things all of a sudden started to fail in a way they had not before; after a
great deal of investigation, it turned out something really minor had changed
in the water supply to the manufacturing facility (perhaps they had started
doing municipal fluoridation, I think).
Noel
Eric, a friend pointed me to your inspiring ClassicCMP post about
getting your 432 online. The photos of your home-made QUIP socket were
really cool.
I reached out today because I've been wanting to hack on a 432 emulator
for some years, ever since I found some contemporary textbooks about the
architecture. Unfortunately, object code in good condition is very hard
to find.
I've been working on some floppy images, but they were taken using a
non-MDS floppy drive from very poor quality media. Progress is slow.
I was wondering if I could have a copy of your microcode dump. I
realize, being microcode, it is not object code in the most meaningful
sense of the word, but it's a lot more than I've been able to locate so far.
Hi all,
Question to the group...not a vintage computer problem. A problem with a
much newer system. An Acer Aspire desktop about 10 years old. I'm trying
to sell it and reset windows (vista) to factory original. It locked up'd
during that process and I reset it. Seems the BIOS is now corrupted. I
need to re-flash the BIOS and to do that I need a bootable CD disk.
I have tried several times to format a brand new disk and make it a boot
disk. Problem is the format option under Windows 8 doesn't allow me to
click that make boot disk option. Any ideas on how to create a boot disk for a
windows vista system? Once I have the boot disk, it's a simple matter to
copy the BIOS files to that disk and re-flash the system. Once it is
started again, I can see what's up with the original Vista or whether i need to
do a full re-load.
I would like any ideas anyone has to offer. I have lots of computer gear
and need to "cull the heard", too much space and I'm moving soon. I hate
to see a buyer slip away.
You can email me directly at _local52mixer at aol.com_
(mailto:local52mixer at aol.com) _or_ (mailto:local52mixer at or) call my cell...732-530-1924.
Thanks in advance,
BD
In a message dated 7/24/2015 1:18:09 A.M. Eastern Daylight Time,
tothwolf at concentric.net writes:
On Wed, 22 Jul 2015, Chuck Guzis wrote:
> On 07/22/2015 10:09 PM, Tothwolf wrote:
>
>> One example I can give are some Pentium P55C architecture (Socket 7)
>> systems which I've been running with minimal downtime for ~15 years.
>> The original power supplies with their original (and relatively low
>> quality) capacitors lasted about 15 to 17 years (I think the
>> manufacture date code stamped on the oldest one was 1998) before the
>> systems began to develop stability issues, requiring me to rebuild the
>> power supplies with new capacitors. I fully expect that the
>> replacements would last even longer than 20 years, however I rather
>> doubt I'll be running those computers by then.
>
> Does anyone have much experience with the so-called "solid electrolyte"
> electrolytics? Fvor replacing vintage caps, they're probably not a
> viable choice as they're mostly SMT, but just wondering...
I believe there are a few webpages out there written by people who have
tried it. From what I remember reading about them years ago, they had no
success when they tried to use them as replacements in switch mode power
supplies (no surprise, since the solid polymer parts they attempted to use
had way to low of ripple current rating for that application) but had
better results with certain PC motherboards.
I use solid polymers as replacements in some applications, and as they
continue to decrease in cost, I've been considering using them more for
replacement of aging SMD aluminum electrolytics. One application where I
particularly like solid polymers is for replacement of the vcore regulator
filter capacitors on Pentium 4 industrial single board computers (yes, the
P4 is still /widely/ used and extremely common in that market, although it
is slowly being replaced by the Core Duo). The original aluminum
electrolytics in that application are usually 6.3V rated parts while the
solid polymer replacements are 2.5V or 4V (vcore is under 2V).
In addition to long term stability, another major benefit to solid
polymers is that unlike aluminum electrolytics and solid tantalums, solid
aluminum polymers they can be used at their full rated voltage with no ill
effects. The only real downside that I know of for a solid polymer is that
they have an incredibly low ESR (less than 0.01 ohm), which can actually
upset older circuit designs which were not designed for capacitors with
such a low ESR.
Devin here, I had asked for advice on how to move a PDP 11 as well as how
to lock the heads on the RL Drives. It was quite a move. Ive never driven
in a large city before, dealing with traffic was more trouble than it was
to move and load up the equipment. Anyhow, i put a few images of what I got
up on a postimage gallery, which can be viewed here :
http://postimg.org/gallery/1xuwq2s6y/
It was at least working for a hour or so....
I was trying to enter a short program at the front panel and there was a
clicking sound followed by a burning smell. I cut the power, the front
panel is unresponsive now, so I'm going to need to look over the power
supply for starters. He did include a second empty PDP 11/34 chassis,
perhaps the power supply in that one is in better condition.
--Devin
> From: Josh Dersch
> I spent some time debating that last night and this morning. Chalk it
> up to me feeling charitable this week ... I thought I'd give the guy a
> break.
Well, the question is, how important is this gear to you? If you've been
looking for one for a decade, that's different from if you just saw it and
said 'that looks cool'. If the latter, yeah, you can be quite charitable.
Which would mean, e.g. that you could agree to pass on enforcing the contract
if the seller agrees to immediately re-list the item in another open auction,
with a minimum reasonable reserve (I'd say $50, myself), and absolute
commitment to go through with the sale, no matter what. After all, an open
auction _is_ the current _real value_ for something.
And they should understand that if they persist in selecting 'local pickup
only', the value of the piece drops by about 75% - or more - it's cutting the
size of the pool of bidders by like 95% (LA area population / total US
population) by doing so.
Noel
All,
forwarded from Cindy at Electronics Plus. Contact eaustin in NY directly if you are interested. No connection, just forwarding.
- Mark
Begin forwarded message:
From: <sales at elecplus.com<mailto:sales at elecplus.com>>
Subject: Old gear avail in NY
Date: July 22, 2015 at 12:49:02 PM CDT
To: Mark Tapley <mtapley at swri.edu<mailto:mtapley at swri.edu>>
I still can't post to the list!
We are looking for wholesale buyers of legacy (early 90?s) PC parts & accessories:
IBM, Tandy, Amiga, Packard Bell, Gateway 2000, etc
Motherboards
Sound Cards - Creative Sound Blaster
Display / Video cards
Hard Drives ? Seagate, Conner, WD, IBM <2GB
Keyboards
& more
Items can be tested before sale if necessary.
Please email eaustin at sunnking.com<mailto:eaustin at sunnking.com> if you are interested in purchasing these or similar items in quantity. Thanks!
He is in NY.
Cindy
The silence may have led you to believe that it was all over. Oh no...
The 10th Vintage Computer Festival is a GO!
Bigger, bolder, nerdier than ever, a wonderful way to tack on our
second digit, VCFMW10 will be held August 29-30 at the Holiday Inn
Chicago-Elk Grove Village. A remarkable convergence of amenities and
price have come together in this spot. Among the features:
- A single 4550 sqft banquet hall - at long last, VCFMW and ECCC shall
truly be one!
- First-floor facilities - no more elevator rides or Level of Discharge!
- 11'x12' loading doors that open direct to the parking lot - you
could drive a truck right into the ballroom, but don't!
- A separate room for talks, videos, quiet time, etc - like we're a
real conference or something!
- No (known) conflicts with holidays, wives' birthdays or other local events!
- The quaint, vaguely Blade Runner-esque surroundings of industrial
parks, truck depots and factories - just the way we like it!
- An on-site restaurant, pool, exercise room, outdoor firepit/smoking
area, shuttle buses to/from the airport and Woodfield mall, close
proximity to fast-food and the two greatest Chicago eateries,
Portillo's and Lou Malnati's! (Seriously, those two alone are reason
enough to attend.)
I have updated the http://vcfmw.org web page and FAQ with most of the
information we have so far. Please give them a read before posting
questions. Hotel room rates will be slightly higher than last year's
$79 at the Fairfield Inn; I am still negotiating the block rate. Due
to the restaurant being on-site, there will be no continental
breakfast. Sorry :(
Now the hard sell: all of this geek-luxury does not come without a
price. Some of you know that the deal we had at the Heron Point was
extraordinary and unheard-of in the event hosting business. Since the
HP no longer rents to the public, we were faced with the choice of
resting on our successful nine-year record or figuring out a way for
the show to go on. And go on it shall...with your help. Without
getting into specifics, the cost of putting on VCFMW has more than
doubled - and we are getting a bargain if our comparison shopping is
to be trusted.
Donation links have been set up on the main VCFMW page for PayPal and
GoFundMe sites. Please use the GFM only if you do not have a PayPal
account, as GFM charges us a fee. If you'd prefer to donate in
person, contact me directly. I will get you a receipt (sorry, we're
not a 501.3c yet, so it won't be tax-free.) The main site features
our non-patented Donate-o-Meter which will (more-or-less) track our
progress. We have a lot of time to reach our goal as payment is not
due until the day of the show.
Extra money raised will be either spent on bonus features for the show
(more space, pizza bar, etc.) or put into a fund for next year. We
will engange with the community as much as possible before making any
decsion regarding extra funds.
There will be much to do between now and August - a new floor plan to
design, tables to allocate, speakers to recruit. But our first big
task is one where everyone can help: let's get the word out! Many of
you are on forums that I am not, so spread the news: the show will go
on!
-j
> From: william degnan
> I told him start with buy it now for $2000 with best offer
And there's the key to the situation. The seller thought they were going to
get big dineros for it, and.... not so much.
Which is likely a good part of why they aren't being reasonable in the
post-sale negotiations with Josh.
> because you're asking for the item to be shipped, the seller can refuse
> on that ground
Err, the listing does say:
"I dont wanna have to mess with shipping, but if you absolutely need it
shipped we can work something out."
So I don't think that dog will hunt.
But, just to close that door, is there anyone in the LA area who can, in
fact, go pick this thing up, and ship it off to Josh? That would leave the
seller without a leg.
But the seller does only have a feedback of 4, so maybe they really are
clueless about eBay.
But the bottom line is that the _reality_ is that honouring the contract with
Josh is _not_ going to cost the seller a lot of money - because in an _open
auction_, it went for.... $5.
Noel
