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
I wrote:
I proposed it, and was willing to build microcontroller-based boards
and write firmware, but IIRC it was decided that there was too little
benefit.
On Thu, Jul 23, 2015 at 12:00 PM, William Donzelli wdonze...@gmail.com wrote:
That seems odd, considering the lengths you guys took on
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
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
As Eric, I'm a member of the PDP-1 Restoration Team. The PDP-1 restoration
was completed in 2005 - and annually we check the power supplies for voltage,
ripple, etc. Not one of the re-formed capacitors have failed in the ten years
since the completion of the restoration.
Did the team ever
On 7/23/2015 12:06 AM, William Donzelli wrote:
As Eric, I'm a member of the PDP-1 Restoration Team. The PDP-1 restoration was
completed in 2005 - and annually we check the power supplies for voltage,
ripple, etc. Not one of the re-formed capacitors have failed in the ten years
since the
On Thu, Jul 23, 2015 at 12:06 AM, William Donzelli wdonze...@gmail.com wrote:
Did the team ever consider some sort of active monitoring of the
power, beyond whatever DEC implemented?
I proposed it, and was willing to build microcontroller-based boards
and write firmware, but IIRC it was decided
On Wed, 22 Jul 2015, tony duell wrote:
On Wed, 22 Jul 2015, Noel Chiappa wrote:
I am way out of my knowledge range in this discussion, but here's
something I wanted to ask about: how do you reconcile this observation
(assertion?) with the observations from several people (e.g. the PDP-1
On Wed, 22 Jul 2015, tony duell wrote:
I think he did answer it. If the unit is operating correctly then the
capacitors must be sufficiently good at that time for that unit.
Now, whether they will go on working is something that is very hard to
tell. But that applies to every other component
Date: Mon, 20 Jul 2015 14:11:46 +
From: tony duell a...@p850ug1.demon.co.uk
Subject: RE: PDP 11 gear finally moved
Replace - yes, *especially* if you don't have a big budget. Aluminum
electrolytic capacitors are CHEAP and easy to obtain. Replacement
semiconductors by comparison
Tail and signaling lights put much more stress on the filament. The
headlights are burned steady in practice and will burn out when they
burn out.
I never replace both, and seldom see any correlation. I just put the
spare in the trunk with the kit to get at the lights when they do fail.
I
On Wed, 22 Jul 2015, tony duell wrote:
Given that a typical aluminum electrolytic capacitor costs anywhere
from $0.12-$0.15 (4mm or 5mm diameter radials) to about $1.00 (12mm or
16mm diameter radial), it also doesn't make much sense to desolder a 20
year old part, spend at a minimum 5 or more
that are running perfectly just in case...
How do you -know- they are running perfectly? Just because a widget
itself is functioning, you have no way of knowing if that capacitor is
working 100% properly /unless/ you actually remove it from circuit and run
a full battery of tests on it.
I might think twice about doing a board that was fragile with age, but
otherwise, change 'em all. Like replacing both headlight bulbs if one
goes out--it's just a matter of time before the other one goes.
Do you seriously replace both headlight bulbs when one fails? I know of
nobody who
They reliably do what they're supposed to do.
You didn't answer the question. How do you know those aluminum
electrolytic capacitors are functioning just as good as they did when they
were new? Unless you've tested them out of circuit, you simply cannot make
That, actually, is the wrong
From: Tothwolf
How do you know those aluminum electrolytic capacitors are functioning
just as good as they did when they were new? Unless you've tested them
out of circuit ...
... aluminum electrolytic capacitors by their very electrochemical
nature degrade as they
really good caps are better than specs and thus deteriorate into
specs over time, but all fade eventually. Some may have connectors
that die before the cap inside. Rarely does a cap actually measure
the same exactly as what is printed on the label. The ESR value vs.
the capacity is the factor,
From: Tothwolf
How do you know those aluminum electrolytic capacitors are functioning
just as good as they did when they were new? Unless you've tested them
out of circuit ...
... aluminum electrolytic capacitors by their very electrochemical
nature degrade as
Do you seriously replace both headlight bulbs when one fails? I know of
nobody who does that. Generally you carry a spare bulb kit and a screwdriver
and if a bulb fails, pull over and change it.
and - like the capacitor replacement question this is an it depends.
For some cars -
From: tony duell a...@p850ug1.demon.co.uk
To: General Discussion: On-Topic and Off-Topic Posts cctalk@classiccmp.org
Sent: Wednesday, 22 July, 2015 12:39:42 PM
Subject: RE: PDP 11 gear finally moved
I might think twice about doing a board that was fragile with age, but
otherwise, change 'em
On Wed, Jul 22, 2015 at 9:33 AM, Tothwolf tothw...@concentric.net wrote:
The only
thing we could know today is if the capacitor passes industry standard tests
and if the power supply those capacitors are a part of functions correctly
when fully loaded.
We built a dummy load for testing the
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
On Wed, 22 Jul 2015, tony duell wrote:
On Wed, 22 Jul 2015, ANDY HOLT wrote:
Do you seriously replace both headlight bulbs when one fails? I know of
nobody who does that. Generally you carry a spare bulb kit and a screwdriver
and if a bulb fails, pull over and change it.
and - like the
On 7/22/15 7:43 AM, Tothwolf wrote:
I can't say I've previously heard of that being done with automotive bulbs
Then why are tail light bulbs sold in pairs?
I just had one go, and replaced both sides.
This thread has gone on for a while and I think we all get the points
here, but one other consideration - how will removing and replacing a
component damage the board? Damage the board and it's game over. One
should always take the overall board's ability to handle replacement.
With the board in
On Mon, 20 Jul 2015 23:14:36 -0600
Eric Smith space...@gmail.com wrote:
On Mon, Jul 20, 2015 at 4:46 PM, Rich Alderson
ri...@livingcomputermuseum.org wrote:
industry white papers with tables of decay rates for
the aluminum electrolytics that indicate that, *no matter what*, they lose
- Original Message -
From: Tothwolf tothw...@concentric.net
Sent: Monday, July 20, 2015 10:03 PM
... I too am getting tired of repeating the same
thing over and over; compiling this sort of
information in a single location might be
helpful.
As it happens I am getting tired of
On Tue, 21 Jul 2015, Mike Stein wrote:
I suspect that the real criterion for whether to shotgun-replace caps is
who is paying/getting paid for the materials and labour ;-).
I dunno about that. When I've done commercial boards such as industrial
process controllers and CPUs for customers with
On 07/21/2015 06:46 PM, Tothwolf wrote:
I dunno about that. When I've done commercial boards such as industrial
process controllers and CPUs for customers with nearly unlimited funds,
I charged the customer based on an hourly rate. Since I use a vacuum
desoldering tool, changing out 10-15
On Tue, 21 Jul 2015, tony duell wrote:
On Mon, 20 Jul 2015, Tothwolf wrote:
Yes, the grid cap would /usually/ be a non-polarized wax paper type,
which tend to be very unreliable. I've yet to find a wax paper type
which will pass a leak test and those are also on my replace on sight
list.
On 07/21/2015 06:56 PM, Tothwolf wrote:
I've often wondered why they even bother to put that polarity stripe on
modern film parts when it doesn't actually indicate the outside foil
terminal. Maybe this is something that has become lost knowledge to
manufacturers over the years to the point
- Original Message -
From: Tothwolf tothw...@concentric.net
To: General Discussion: On-Topic and Off-Topic
Posts cctalk@classiccmp.org
Sent: Tuesday, July 21, 2015 9:46 PM
Subject: Re: PDP 11 gear finally moved
On Tue, 21 Jul 2015, Mike Stein wrote:
...
FWIW I'm certainly not about
Rich Alderson ri...@livingcomputermuseum.org wrote:
From: Peter Coghlan
Sent: Saturday, July 18, 2015 1:27 AM
Rich Alderson ri...@livingcomputermuseum.org wrote:
It is generally a good idea to re-form electrolytic capacitors in power
supplies, and to bench check the power supplies (under
On Mon, 20 Jul 2015, Rich Alderson wrote:
the aluminum electrolytics that indicate that, *no matter what*, they
lose capacitance over time, until c. 14 years from manufacturer date
they are at 10% of rating.
Please excuse me, but this is utter nonsense.
Most electrolytics in our machines are
But yes, selenium rectifiers rarely work now (although there are exceptions)
and when they fail they can take out the mains transformer. And they smell
horrible (think of school dinner cabbage!)
Huh? All devices with selenium rectifiers that I/we own are OK. And a
selenium rectifier
On Tue, 21 Jul 2015, tony duell wrote:
But yes, selenium rectifiers rarely work now (although there are exceptions)
and when they fail they can take out the mains transformer. And they smell
horrible (think of school dinner cabbage!)
Huh? All devices with selenium rectifiers that I/we own are
On Sun, 19 Jul 2015, dwight wrote:
I have rarely seen static damage to electronic parts. I can imagine that
if I were in Nevada during winter time, I might see more. There were
times when, even with a key to be the discharge point that my arm still
jumped.
On parts, the ones I've seen that I
From: a...@p850ug1.demon.co.uk
To: cctalk@classiccmp.org
Subject: RE: PDP 11 gear finally moved
Date: Sun, 19 Jul 2015 14:35:52 +
Be careful, static daamge does not always show up at the time. You can
damage an IC, have it work for some time afterwards and then fail.
I'm
On 07/19/2015 02:03 AM, tony duell wrote:
So, tony, if I'm correct, you just called bullshit, right?
I assume this relates to my comments on static damage of PDP11 PSUs,
I am not sure I would quite put it that way (not on a public list :-)) but (a)
I have never seen a DEC
PSU (in a PDP11 or
If I may go back to the original post topic for a moment, what model is that
line printer that is pictured? I'm on the lookout for a DEC LP32 to go with my
11/730.
Now on the topic of capacitors: The only component type that I replace on sight
at this point are the Rifa paper-dielectric EMI
On Mon, 20 Jul 2015, tony duell wrote:
Replace - yes, *especially* if you don't have a big budget. Aluminum
electrolytic capacitors are CHEAP and easy to obtain. Replacement
semiconductors by comparison are expensive and can be quite difficult
to find.
Err, have you priced the
On Mon, 20 Jul 2015, Rich Alderson wrote:
On Sat, 18 Jul 2015, Peter Coghlan wrote:
Rich Alderson ri...@livingcomputermuseum.org wrote:
It is generally a good idea to re-form electrolytic capacitors in
power supplies, and to bench check the power supplies (under some
kind of load) before
On Mon, 20 Jul 2015, Mark J. Blair wrote:
Now on the topic of capacitors: The only component type that I replace
on sight at this point are the Rifa paper-dielectric EMI suppression
caps. Had one go incendiary on me so far, and I do a replace-on-sight
routine on them because my hypothesis of
On Jul 20, 2015, at 18:02 , Tothwolf tothw...@concentric.net wrote:
I replace wax paper types with polyester (mylar), polystyrene or ceramic
discs, depending on how they are used in the circuit (note however that for
wound foil types, modern replacement parts do not mark the outside foil,
From: Peter Coghlan
Sent: Saturday, July 18, 2015 1:27 AM
Rich Alderson ri...@livingcomputermuseum.org wrote:
It is generally a good idea to re-form electrolytic capacitors in power
supplies, and to bench check the power supplies (under some kind of
load) before actually applying power to
I've not replaced any in a PDP11 power supply, however I have replaced
them in other equipment with equally large PSUs. In the odd case where a
computer grade screw terminal capacitor is extremely expensive or
completely unobtainable (those which I've purchased were under $20-30) I
might be
On Mon, Jul 20, 2015 at 4:46 PM, Rich Alderson
ri...@livingcomputermuseum.org wrote:
industry white papers with tables of decay rates for
the aluminum electrolytics that indicate that, *no matter what*, they lose
capacitance over time, until c. 14 years from manufacturer date they are at
10%
So, tony, if I'm correct, you just called bullshit, right?
I assume this relates to my comments on static damage of PDP11 PSUs,
I am not sure I would quite put it that way (not on a public list :-)) but (a)
I have never seen a DEC
PSU (in a PDP11 or elsewhere) damaged by static, certainly
On Fri, 17 Jul 2015, tony duell wrote:
Perhaps. But not all of it, certainly. I'm currently four for four
fixing dead flatscreens by re-capping their power supplies; I imagine
others have similar experiences. It's not a huge stretch to imagine
This could be taken to show that modern
I have rarely seen static damage to electronic parts. I can imagine
that if I were in Nevada during winter time, I might see more. There
were times when, even with a key to be the discharge point that
my arm still jumped.
Be careful, static daamge does not always show up at the time. You
Well, all I can say is that my experience differs. I have had newer capacitors
fail, and old ones, too, of course, but nothing points to wholesale replacement
as a cost or time effective strategy, especially on something like an Altair.
FWIW, I don't run my vintage machines all that often.
I have rarely seen static damage to electronic parts. I can imagine
that if I were in Nevada during winter time, I might see more. There
were times when, even with a key to be the discharge point that
my arm still jumped.
On parts, the ones I've seen that I could definitely attribute to static
What I am wondering about, though, is the extra current they draw while
they are forming up while the power supply is running. The capacitor
might survive it (not get so hot that it fails), but the things supply
the higher than ordinary current to it might not. Killed a bridge
rectifier on a
Rich Alderson ri...@livingcomputermuseum.org wrote:
It is generally a good idea to re-form electrolytic capacitors in power
supplies, and to bench check the power supplies (under some kind of
load) before actually applying power to the whole unit.
It is always a good idea to replace
Oh, sorry, didn't realize they used switchers for the PDP-11s.
However I was talking with a friend of mine last night about my error,
and he told me that the switching supplies for the PDP-11s were very
unreliable back in the day. He often had to troubleshoot the machines
back then. A common
Oh, sorry, didn't realize they used switchers for the PDP-11s.
There have been _many_ DEC PSU designed used for the PDP11. I think all of them
used some
kind of switching regulator for the +5V line. A quick glance at the printsets
will settle it..
However I was talking with a friend of
More myths and ledgends.
As I remember it this all started with the arrival of FET's having a
very high input impedance due to narrow gate areas.
If you were daft enough not to have a path to earth
and let a charge build up on the gate then you could exceed the
breakdown voltage across the
On 07/17/2015 11:17 PM, tony duell wrote:
On the other hand if the +5V line did get too high it could have wiped out
just about every IC in the unit. Ouch!. I've only ever had this happen once, and
it was in a much lesser machine than a PDP11 (fortunately).
Many years ago, I managed to feed
So, tony, if I'm correct, you just called bullshit, right?
--
--- Dave Woyciesjes
--- ICQ# 905818
--- CompTIA A+ Certified IT Tech -http://certification.comptia.org/--- HDI
Certified Support Center Analyst -http://www.ThinkHDI.com/Registered Linux user
number 464583
Computers have lots of
I do find this witch-hunt against capacitors to be curious, given how
few I've found to have failed. I suspect a lot of it comes from
audiophools who think this is the way to fix anything...
Perhaps. But not all of it, certainly. I'm currently four for four
fixing dead flatscreens by
some are good some are bad.
http://www.badcaps.net/
here is all the info you ever need on today's bad caps
not so much on yesteryears bad caps
On 7/17/2015 11:53 AM, Mouse wrote:
I do find this witch-hunt against capacitors to be curious, given how
few I've found to have failed. I
I suspect part of the swap'em ALL out mentality comes from the 90's when
some botched industrial espionage had some of the bottom-tier cap
manufacturers using a dodgy electrolytic formula for their caps. These
caps would have a frequent failure rate..
While not an issue for pre-90's electronics,
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
It is generally a good idea to re-form electrolytic capacitors in power
supplies, and to bench check the power supplies (under some kind of
load) before actually applying power to the whole unit.
It is always a good idea to replace electrolytic capacitors in power supplies.
Could you,
It is generally a good idea to re-form electrolytic capacitors in power
supplies, and to bench check the power supplies (under some kind of
load) before actually applying power to the whole unit.
JRJ
On 7/17/2015 11:49 AM, devin davison wrote:
Devin here, I had asked for advice on how to move a
It is generally a good idea to re-form electrolytic capacitors in power
supplies, and to bench check the power supplies (under some kind of
load) before actually applying power to the whole unit.
I am not sure either would have done much good here. The OP said it
ran OK for an hour or so,
It is generally a good idea to re-form electrolytic capacitors in power
supplies, and to bench check the power supplies (under some kind of
load) before actually applying power to the whole unit.
It is always a good idea to replace electrolytic capacitors in power supplies.
The rest of the
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
Did you see anything on the panel when it died (was the numeric display still
On 2015-Jul-17, at 11:42 AM, tony duell wrote:
It is generally a good idea to re-form electrolytic capacitors in power
supplies, and to bench check the power supplies (under some kind of
load) before actually applying power to the whole unit.
It is always a good idea to replace electrolytic
That might be a little different -- much more recent - presumably in the
ear of flat screens and PCs where there have been times when
manufacturers got fed bad capacitors for their boards - which then
failed later. IBM replaced a whole series of motherboards in one
organization that I worked at
I tend to agree with your hunch.
On 7/17/2015 1:55 PM, Todd Killingsworth wrote:
I suspect part of the swap'em ALL out mentality comes from the 90's when
some botched industrial espionage had some of the bottom-tier cap
manufacturers using a dodgy electrolytic formula for their caps. These
Thank you for the detailed information. I need to figure out how im going
to get it out of the rack and moved to a place where i can test it over the
next couple days where it will not be in the way. Ill find some way to do
a dummy load and do an extended test to be sure the supply is working
I was operating the panel when i first got it, now the numbers do not light
up, panel is unresponsive, and run light stays lit.(just describing the
behavior, i will not start it back up till I work on the power supply)
On Fri, Jul 17, 2015 at 3:50 PM, devin davison lyokob...@gmail.com wrote:
I
On 07/17/2015 11:53 AM, Mouse wrote:
I do find this witch-hunt against capacitors to be curious, given how
few I've found to have failed. I suspect a lot of it comes from
audiophools who think this is the way to fix anything...
Perhaps. But not all of it, certainly. I'm currently four for
U - his PDP-11/34 most certainly does use switching power
regulators. ;)
On 7/17/2015 4:06 PM, John Robertson wrote:
On 07/17/2015 11:53 AM, Mouse wrote:
I do find this witch-hunt against capacitors to be curious, given how
few I've found to have failed. I suspect a lot of it comes from
-Original Message-
From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of tony
duell
Sent: 17 July 2015 20:23
To: General Discussion: On-Topic and Off-Topic Posts
Subject: RE: PDP 11 gear finally moved
When I repaired my VT100s I had to replace all the electrolytic
Replace - no, I don't agree - especially not for those of us who don't
have the kind of budget that your organization has. In my experience,
for equipment of this quality and vintage, 95% or more of the time an
hour to a few hours of re-forming is all that is necessary - and as Tony
has pointed
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