10 Dec
2010
10 Dec
'10
12:06 p.m.
And remember, if it's not 36 bits, you're not playing with a full DEC!
10 Dec
10 Dec
1:14 p.m.
On Fri, Dec 10, 2010 at 12:06 PM, Daniel Seagraves
<dseagrav at lunar-tokyo.net> wrote:
And remember, if it's not 36 bits, you're not
playing with a full DEC!
XKLeTen@ r zork
The dungeon is available for exploring Monday thru Friday:
00:00 - 24:00
It is also open weekends and holidays.
Welcome to Dungeon.
This version created March 30.
You are in an open field west of a big white house, with a boarded
front door.
There is a small mailbox here.
2:31 p.m.
From: Ethan Dicks
Sent: Friday, December 10, 2010 10:14 AM
On Fri, Dec 10, 2010 at 12:06 PM, Daniel Seagraves
<dseagrav at lunar-tokyo.net> wrote:
> And remember, if it's not 36 bits, you're
not playing with a full DEC!
XKLeTen@ r zork
The dungeon is available for exploring Monday thru
Friday:
00:00 - 24:00
It is also open weekends and holidays.
Welcome to Dungeon.
This version created March 30.
You are in an open field west of a big white house, with a boarded
front door.
There is a small mailbox here.
Hey, Ethan, I was on the Toad-1 creating a couple of accounts (requests
do come in from time to time, even now), and saw that you were running
Zork. Talk about timing--you could have been there and left before I
got on, or after.
Rich Alderson
Vintage Computing Sr. Server Engineer
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104
mailto:RichA at vulcan.com
mailto:RichA at LivingComputerMuseum.org
http://www.PDPplanet.org/
http://www.LivingComputerMuseum.org/
2:24 p.m.
And remember, if it's not 36 bits, you're not playing with a full DEC!
Reminds me of a converstaion a fried of mine had with another chap
shortly after I';d obtained a much lesser machine (a PDP11) and was
looking for various bits for lit, like a DL11...
"I've got a mad firend with a PDP11"
"How can you possibly call anyone who owns a PDP11 'mad'"
"Well, he's a few cards short of a full DEC"
-tony
3:34 p.m.
On Dec 10, 2010, at 1:24 PM, Tony Duell wrote:
Geez, if he thinks a guy win an 11 is mad, I wonder where that puts me... -_-
And remember, if it's not 36 bits, you're not playing with a full DEC!
Reminds me of a converstaion a fried of mine had with another chap
shortly after I';d obtained a much lesser machine (a PDP11) and was
looking for various bits for lit, like a DL11...
"I've got a mad firend with a PDP11"
"How can you possibly call anyone who owns a PDP11 'mad'"
"Well, he's a few cards short of a full DEC" 
4:23 p.m.
On Fri, 10 Dec 2010, Daniel Seagraves wrote:
On Dec 10, 2010, at 1:24 PM, Tony Duell wrote:
Geez, if he thinks a guy win an 11 is mad, I wonder where that puts me... -_-
Well, I was pretty mad back when I was short of a full DEC in my PDP-11! :-)
These days I'm quite happy with my -11's except over the space they take up.
As for you? The word that comes to mind isn't "Mad", but rather
"Brave".
I'm personally scared of the idea of owning a KS10.
Zane
And remember, if it's not 36 bits, you're not playing with a full DEC!
Reminds me of a converstaion a fried of mine had with another chap
shortly after I';d obtained a much lesser machine (a PDP11) and was
looking for various bits for lit, like a DL11...
"I've got a mad firend with a PDP11"
"How can you possibly call anyone who owns a PDP11 'mad'"
"Well, he's a few cards short of a full DEC" 
4:47 p.m.
On 12/10/10 4:23 PM, Zane H. Healy wrote:
Well, I was pretty mad back when I was short of a full
DEC in my PDP-11!
:-)
These days I'm quite happy with my -11's except over the space they take
up.
I very happily give my space to PDP-11s. =)
As for you? The word that comes to mind isn't
"Mad", but rather
"Brave". I'm personally scared of the idea of owning a KS10.
I have a KS10. The only scary part about it is not having enough time
to do anything with it.
-Dave
--
Dave McGuire
Port Charlotte, FL
5:33 p.m.
On Fri, 10 Dec 2010, Dave McGuire wrote:
I have a KS10. The only scary part about it is not
having enough time
to do anything with it.
Though thought of needing a spare part is what scares me. I doubt a KS10 is
that much worse than my PDP-11/44, but the thought of needing spares scares
me.
Zane
5:37 p.m.
On 12/10/10 5:33 PM, Zane H. Healy wrote:
I'm lucky to have a bunch of spares. But as I recall it's mostly TTL
anyway; not too tough to troubleshoot.
Speaking of spares, you wouldn't happen to have a spare top cover for
an 11/44, would you?
-Dave
--
Dave McGuire
Port Charlotte, FL
I have a
KS10. The only scary part about it is not having enough time
to do anything with it.
Though thought of needing a spare part is what scares me. I doubt a
KS10 is
that much worse than my PDP-11/44, but the thought of needing spares scares
me.
5:44 p.m.
On Fri, 10 Dec 2010, Dave McGuire wrote:
Speaking of spares, you wouldn't happen to have a
spare top cover for
an 11/44, would you?
I'm afraid not.
Something to keep in mind is that there were apparently more than one
Chassis used in /44's. So the tops might be different. I have figured out
how to get the chassis out of the rack, that made moving it the first time
"interesting". The second time we just rolled it up into the bed of my
Pickup.
Zane
5:47 p.m.
On 12/10/10 5:44 PM, Zane H. Healy wrote:
Mine has an 11/24 lid on it. :-( Well, the lid is compatible, but the
module placement sticker on the top says "11/24" (with KDF11-UA, etc)
and I'm a bit anal sometimes. ;)
Speaking of
spares, you wouldn't happen to have a spare top cover for
an 11/44, would you?
I'm afraid not. Something to keep in mind is that there were
apparently more than one
Chassis used in /44's. So the tops might be different. I have figured out
how to get the chassis out of the rack, that made moving it the first time
"interesting". The second time we just rolled it up into the bed of my
Pickup.
Ahh ok, gotcha. Thanks for the tip!
-Dave
--
Dave McGuire
Port Charlotte, FL
11 Dec
11 Dec
4:07 a.m.
Though thought
of needing a spare part is what scares me. I doubt a
KS10 is
that much worse than my PDP-11/44, but the thought of needing spares scares
me.
I'm lucky to have a bunch of spares. But as I recall it's mostly TTL
anyway; not too tough to troubleshoot. 
10 Dec
10 Dec
5:37 p.m.
Though thought of needing a spare part is what scares
me. ?I doubt a KS10 is
that much worse than my PDP-11/44, but the thought of needing spares scares
me.
The problem with running a KS10 is that there is a very restrictive
list of disks and tapes it will play with.
--
Will
11 Dec
11 Dec
4:11 a.m.
On Fri, Dec 10, 2010 at 05:37:33PM -0500, William Donzelli wrote:
Didn't Ian and the guys at the Living Computer Museum (formerly
PDPplanet) work on a massbuss "emulator" of sorts? That should be
modifiable to work with the 18 bit KS-10 version?
Or am I missing something? I'm unsure what happened with that project.
- Pontus
Though thought
of needing a spare part is what scares me. ?I doubt a KS10 is
that much worse than my PDP-11/44, but the thought of needing spares scares
me.
The problem with running a KS10 is that there is a very restrictive
list of disks and tapes it will play with.
13 Dec
13 Dec
3:31 p.m.
From: Pontus Pihlgren
Sent: Saturday, December 11, 2010 1:12 AM
On Fri, Dec 10, 2010 at 05:37:33PM -0500, William Donzelli wrote:
> The problem with running a KS10 is that there is a
very restrictive
> list of disks and tapes it will play with.
Didn't Ian and the guys at the Living Computer
Museum (formerly
PDPplanet) work on a massbuss "emulator" of sorts? That should be
modifiable to work with the 18 bit KS-10 version?
Or am I missing something? I'm unsure what
happened with that project.
As it happens, we are about to send out the artwork for the second revision
of the Massbus Disk Emulator this week (a project which predates Ian by a
couple of years!). We've been waiting for Rabbit to bring out a faster
processor than the one in the original design, and changing the way that
register shadowing is done.
There is no such thing, by the way, as "the 18 bit KS-10 version"--Massbus
is Massbus, no matter whether it is talking to an RH20 on a KL-10, an RH70
on a PDP-11/70, an RH15 on a PDP-15, or an RH11 on other PDP-11 models.
They're *all* 18 bits of data, though the 16-bit systems don't use 2 bits
of that.
Anyway, the MDE looks like a string of disks on a Massbus channel (only
RP06 currently, but that will change soon) to the vintage system. Disk
images are represented as directories of track files on an FTP server.
(100baseT Ethernet keeps up with Massbus very nicely.)
Once we have more than the breadboard prototype running (on the 2065 that
Ian mentioned up-thread), we'll hook one to a KS-10, as well as to our
PDP-11/70 and PDP-11/45, and see what we can shake loose.
Rich Alderson
Vintage Computing Sr. Server Engineer
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104
mailto:RichA at vulcan.com
mailto:RichA at LivingComputerMuseum.org
http://www.PDPplanet.org/
http://www.LivingComputerMuseum.org/
3:44 p.m.
On Mon, Dec 13, 2010 at 3:31 PM, Rich Alderson <RichA at vulcan.com> wrote:
As it happens, we are about to send out the artwork
for the second revision
of the Massbus Disk Emulator this week
Cool!
Once we have more than the breadboard prototype
running (on the 2065 that
Ian mentioned up-thread), we'll hook one to a KS-10, as well as to our
PDP-11/70 and PDP-11/45, and see what we can shake loose.
Do you have an RH-750 and 11/750 to test against? (My first 11/750
ran for years with an RH750 and TU78 next to an SI-9900 w/CMI
interface for disk - when my employer closed, I was able to rescue the
CPU, but the tape drive was too large and needed 220VAC so was not
rescued).
I'm sure in the grand scheme of MASSBUS-using systems, the 11/750 is a
thin sliver of a minority, but they were out there. Hopefully any
proper MASSBUS emulator should work without any strangeness.
-ethan
4:03 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Ethan Dicks
Sent: Monday, December 13, 2010 12:44 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Happy DEC-10 everyone!
On Mon, Dec 13, 2010 at 3:31 PM, Rich Alderson <RichA at vulcan.com>
wrote:
Our emails crossed. :-) We do have an RH780 on each of our VAX-11/78x's. We're
currently using CI for OpenVMS 6.2 -- Ian
As it happens, we are about to send out the
artwork for the second
revision
of the Massbus Disk Emulator this week
Cool!
Once we have more than the breadboard prototype
running (on the 2065
that
Ian mentioned up-thread), we'll hook one to a
KS-10, as well as to
our
PDP-11/70 and PDP-11/45, and see what we can
shake loose.
Do you have an RH-750 and 11/750 to test against? (My first 11/750
ran for years with an RH750 and TU78 next to an SI-9900 w/CMI
interface for disk - when my employer closed, I was able to rescue the
CPU, but the tape drive was too large and needed 220VAC so was not
rescued).
I'm sure in the grand scheme of MASSBUS-using systems, the 11/750 is a
thin sliver of a minority, but they were out there. Hopefully any
proper MASSBUS emulator should work without any strangeness.
4:05 p.m.
From: Ethan Dicks
Sent: Monday, December 13, 2010 12:44 PM
On Mon, Dec 13, 2010 at 3:31 PM, Rich Alderson <RichA at vulcan.com> wrote:
> As it happens, we are about to send out the
artwork for the second revision
> of the Massbus Disk Emulator this week
Cool!
> Once we have more than the breadboard prototype
running (on the 2065 that
> Ian mentioned up-thread), we'll hook one to a KS-10, as well as to our
> PDP-11/70 and PDP-11/45, and see what we can shake loose.
Do you have an RH-750 and 11/750 to test against? (My
first 11/750
ran for years with an RH750 and TU78 next to an SI-9900 w/CMI
interface for disk - when my employer closed, I was able to rescue the
CPU, but the tape drive was too large and needed 220VAC so was not
rescued).
I'm sure in the grand scheme of MASSBUS-using
systems, the 11/750 is a
thin sliver of a minority, but they were out there. Hopefully any
proper MASSBUS emulator should work without any strangeness.
I knew I forgot a system. We have an RH780 in each 11/785, so we'll be
testing against that, too.
We don't have an 11/750 in the collection, or we'd try that, too.
Rich Alderson
Vintage Computing Sr. Server Engineer
Vulcan, Inc.
505 5th Avenue S, Suite 900
Seattle, WA 98104
mailto:RichA at vulcan.com
mailto:RichA at LivingComputerMuseum.org
http://www.PDPplanet.org/
http://www.LivingComputerMuseum.org/
4:10 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Rich Alderson
Sent: Monday, December 13, 2010 1:06 PM
To: 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: Happy DEC-10 everyone!
From: Ethan Dicks
Sent: Monday, December 13, 2010 12:44 PM
On Mon, Dec 13, 2010 at 3:31 PM, Rich Alderson <RichA at vulcan.com>
wrote:
And if someone wants to give us one.... ;-)
> As it happens, we are about to send out the
artwork for the second
revision
> of the Massbus Disk Emulator this week
Cool!
> Once we have more than the breadboard
prototype running (on the 2065
that
> Ian mentioned up-thread), we'll hook one
to a KS-10, as well as to
our
> PDP-11/70 and PDP-11/45, and see what we can
shake loose.
Do you have an RH-750 and 11/750 to test against?
(My first 11/750
ran for years with an RH750 and TU78 next to an SI-9900 w/CMI
interface for disk - when my employer closed, I was able to rescue
the
CPU, but the tape drive was too large and needed
220VAC so was not
rescued).
I'm sure in the grand scheme of MASSBUS-using
systems, the 11/750 is
a
thin sliver of a minority, but they were out
there. Hopefully any
proper MASSBUS emulator should work without any strangeness.
I knew I forgot a system. We have an RH780 in each 11/785, so we'll be
testing against that, too.
We don't have an 11/750 in the collection, or we'd try that, too.
4:11 p.m.
On Mon, Dec 13, 2010 at 4:05 PM, Rich Alderson <RichA at vulcan.com> wrote:
From: Ethan Dicks
Good to hear.
Do you have an RH-750 and 11/750 to test against?
I knew I forgot a system. ?We have an RH780 in each 11/785, so we'll be
testing against that, too. We don't have an 11/750 in the collection, or
we'd try that, too.
Knowing it's going to be tested on an RH780 is close enough for my
interests. I've only had my own hands on the RH11 and the RH750, but
except for overall throughput limitations on the RH11 (which, for the
uninitiated, is why the RM02 spins slower than the RM03), what works
on one, works on all.
I look forward to hearing news of success!
-ethan
4:02 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Rich Alderson
Sent: Monday, December 13, 2010 12:31 PM
To: 'General Discussion: On-Topic and Off-Topic Posts'
Subject: RE: Happy DEC-10 everyone!
From: Pontus Pihlgren
Sent: Saturday, December 11, 2010 1:12 AM
On Fri, Dec 10, 2010 at 05:37:33PM -0500, William Donzelli wrote:
I'm looking forward to qualifying it on our VAX-11s, too, so we can run Ultrix on one
of them. -- Ian
> The problem with running a KS10 is that there
is a very restrictive
> list of disks and tapes it will play with.
Didn't Ian and the guys at the Living
Computer Museum (formerly
PDPplanet) work on a massbuss "emulator" of sorts? That should be
modifiable to work with the 18 bit KS-10 version?
Or am I missing something? I'm unsure what
happened with that
project.
As it happens, we are about to send out the artwork for the second
revision
of the Massbus Disk Emulator this week (a project which predates Ian by
a
couple of years!). We've been waiting for Rabbit to bring out a faster
processor than the one in the original design, and changing the way
that
register shadowing is done.
There is no such thing, by the way, as "the 18 bit KS-10 version"--
Massbus
is Massbus, no matter whether it is talking to an RH20 on a KL-10, an
RH70
on a PDP-11/70, an RH15 on a PDP-15, or an RH11 on other PDP-11 models.
They're *all* 18 bits of data, though the 16-bit systems don't use 2
bits
of that.
Anyway, the MDE looks like a string of disks on a Massbus channel (only
RP06 currently, but that will change soon) to the vintage system. Disk
images are represented as directories of track files on an FTP server.
(100baseT Ethernet keeps up with Massbus very nicely.)
Once we have more than the breadboard prototype running (on the 2065
that
Ian mentioned up-thread), we'll hook one to a KS-10, as well as to our
PDP-11/70 and PDP-11/45, and see what we can shake loose.
10 Dec
10 Dec
7:36 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Dave McGuire
Sent: Friday, December 10, 2010 1:48 PM
To: On-Topic and Off-Topic Posts
Subject: Re: Happy DEC-10 everyone!
On 12/10/10 4:23 PM, Zane H. Healy wrote:
We have a KL-10. Now that's a whole lotta machine! :-) -- Ian
Well, I was pretty mad back when I was short of a
full DEC in my PDP-
11!
:-)
These days I'm quite happy with my -11's except over the space they
take
up.
I very happily give my space to PDP-11s. =)
As for you? The word that comes to mind
isn't "Mad", but rather
"Brave". I'm personally scared of the idea of owning a KS10.
I have a KS10. The only scary part about it is not having enough
time
to do anything with it.
-Dave
10:31 p.m.
On 12/10/10 7:36 PM, Ian King wrote:
We have a KL-10. Now that's a whole lotta machine! :-) -- Ian
Hooboy yes!
-Dave
--
Dave McGuire
Port Charlotte, FL
Well, I was pretty mad back when I was short of a full
DEC in my PDP-
11!
:-)
These days I'm quite happy with my -11's except over the space they
take
up.
I very happily give my space to PDP-11s. =)
As for you? The word that comes to mind
isn't "Mad", but rather
"Brave". I'm personally scared of the idea of owning a KS10.
I have a KS10. The only scary part about it is not having enough
time
to do anything with it.
11 Dec
11 Dec
2:54 p.m.
Geez, if he thinks a guy win an 11 is mad, I wonder
where that puts me... -_-
I don;t think he thought I was mad _because_ I owned a PDP11.
He described me as 'mad' because, well, how many sane people read service
manuals as 'light bedtime reading'.
[Surely nobody here thinks I'm sane, do they???]
-tony
5:59 p.m.
On Fri, Dec 10, 2010 at 4:57 PM, ben <bfranchuk at jetnet.ab.ca> wrote:
On 12/10/2010 10:06 AM, Daniel Seagraves wrote:
If they were in the same box they might... (I have a CompuServe
"Trinode" - three 9-slot Qbus backplanes, three power supplies, three
reset buttons, one cube-like enclosure - that's a 48-bit processor,
right? ;-)
-ethan
And remember, if it's not 36 bits, you're not playing with a full DEC!
So does having 3 PDP8's count? 
9:44 p.m.
New subject: Capacitors -- replacements?
List,
I've got a lovely old Lambda power supply here (linear +/-15, +/-5)
that uses an old Sprague screw-mount (Computerlytic) capacitor. It's
rated at 34000uF, 15WVDC. It's all dried out, so it needs
replacement.
It looks as if it's going to be difficult to find a working exact
replacement.
What in your experience works best in these applications? Plain old
"snap in" electrolytics? Anyone have any hints on making the
replacement fit the larger footprint?
Thanks,
Chuck
11:44 p.m.
New subject: Capacitors -- replacements?
Hi
What demensions is it? There is a surplus place
near here that often has screw mount type caps
( NOS ). also look for any caps that say they are long
life electrolytics. These will also be bad.
Dwight
From: cclist at sydex.com
To: cctalk at classiccmp.org
Date: Fri, 10 Dec 2010 18:44:51 -0800
Subject: Capacitors -- replacements?
List,
I've got a lovely old Lambda power supply here (linear +/-15, +/-5)
that uses an old Sprague screw-mount (Computerlytic) capacitor. It's
rated at 34000uF, 15WVDC. It's all dried out, so it needs
replacement.
It looks as if it's going to be difficult to find a working exact
replacement.
What in your experience works best in these applications? Plain old
"snap in" electrolytics? Anyone have any hints on making the
replacement fit the larger footprint?
Thanks,
Chuck
11:54 p.m.
New subject: Capacitors -- replacements?
On 10 Dec 2010 at 20:44, dwight elvey wrote:
Hi
What demensions is it? There is a surplus place
near here that often has screw mount type caps
( NOS ). also look for any caps that say they are long
life electrolytics. These will also be bad.
Hi Dwight,
Funny you should mention that--the cap in question is indeed labeled
"Long Life". It's about 3" H x 2" in diameter.
--Chuck
11 Dec
11 Dec
9:46 a.m.
New subject: Capacitors -- replacements?
Hi
I have a couple of smaller Lambda bench supplies.
They have a number of electrlytics in them but almost
every one that is marked "Lambda Long Life" has failed.
They are nice supplies so I keep fixing them.
They seem to mostly go dry as yours has rather
than going short. I'd rather this as it save solid state
parts around them.
As long as you aren't expecting 100% capacitance
and supper low ESR, the ones they have seem fine.
I had one failing in a Poly88 chassis. I replaced it
with one of the units they had and it has been working
fine ever since. I think most of theirs were made in the
90's so there not all that old.
Dwight
From: cclist at sydex.com
On 10 Dec 2010 at 20:44, dwight elvey wrote:
Hi
What demensions is it? There is a surplus place
near here that often has screw mount type caps
( NOS ). also look for any caps that say they are long
life electrolytics. These will also be bad.
Hi Dwight,
Funny you should mention that--the cap in question is indeed labeled
"Long Life". It's about 3" H x 2" in diameter.
--Chuck
10 Dec
10 Dec
11:57 p.m.
New subject: Capacitors -- replacements?
Check here off hand
11 Dec
11 Dec
2:58 a.m.
New subject: Capacitors -- replacements?
On 10 Dec 2010 at 21:57, ben wrote:
Check here off hand
> http://www.surplussales.com/Capacitors/Electrolytics/10000uF-300000u
> F.html
Nothing exact, but some pretty close-enough stuff.
How reliable are these NOS caps? They've got to be pretty old.
--Chuck
3:54 a.m.
New subject: Capacitors -- replacements?
That's the punch line of "NOS" capacitors: if they are as old as the ones
you're replacing, you're replacing crap with crap. Many folks have noted that
caps sitting on the shelf aren't any better off than those sitting in a power supply.
When I was rebuilding power supplies on our VAX-11s, I sought replacement units with as
close physical dimensions as I could find. In one case, I had to use a Dremel tool to
"oval out" the mounting holes to fit the new units. The PCB had plenty of
plating to accommodate the new spacing, or this would not have been successful. YMMV.
If the new caps are dramatically smaller than the originals and you are not seeking to
perform historical restoration, perhaps consider caps with wire leads, crimp-fit lugs on
the leads and screw/nut fasteners through the original PCB holes. I think the idea of
hollowing out the original caps is "too much work to have fun." I'd far
rather document for future generations (since I'm doing a historical restoration) why
I "ovalled" the holes or otherwise mounted a capacitor of different dimensions
-- Ian
________________________________________
From: cctalk-bounces at classiccmp.org [cctalk-bounces at classiccmp.org] On Behalf Of
Chuck Guzis [cclist at sydex.com]
Sent: Friday, December 10, 2010 11:58 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Capacitors -- replacements?
On 10 Dec 2010 at 21:57, ben wrote:
Check here off hand
> http://www.surplussales.com/Capacitors/Electrolytics/10000uF-300000u
> F.html
Nothing exact, but some pretty close-enough stuff.
How reliable are these NOS caps? They've got to be pretty old.
--Chuck
11:31 a.m.
New subject: Capacitors -- replacements?
On 11 Dec 2010 at 0:54, Ian King wrote:
That's the punch line of "NOS"
capacitors: if they are as old as the
ones you're replacing, you're replacing crap with crap. Many folks
have noted that caps sitting on the shelf aren't any better off than
those sitting in a power supply.
That's what I suspected. I like your idea of crimping a couple of
lugs on on a radial lead modern electrolytic. Fortunately, the rest
of the capacitors that have bit the dust are axial-lead jobs and not
much of a bother to replace.
I wonder if modern capacitors are better than the old ones in this
respect. After all, they've been engineered to withstand use in
switching power supplies, so working with a 120Hz ripple should be
pretty easy.
I'm with Dwight on the Lambdas being well-built supplies. Huge
heatsinks on this thing, given its ratings.
--Chuck
12:50 p.m.
New subject: Capacitors -- replacements?
That's the punch line of "NOS"
capacitors: if they are as old as the ones you're replacing, you're replacing crap
with crap. ?Many folks have noted that caps sitting on the shelf aren't any better off
than those sitting in a power supply.
I would not damn NOS caps quite so fast. Capacitor technology really
improved in the 1960s, so the caps of the 1970s and especially 80s and
90s are really quite good.
With NOS caps, I think it all boils down to two things. One is the
age, being made sometime post-1970, after the cap makers really got
their act together. The other, and probably more important, is where
the caps came from. Storage conditions matter quite a lot. I suspect
that a huge share of electrolytic capacitor failures we see are not
due to whole improper/impossible reformation process, but rather by
the seals going bad and contaminants getting in. Thus, getting NOS
parts from a surplus dealer that keeps half of his stock in
non-climate control building is probably not a good place to get the
caps. Every year, the temperature cycles from freezing to baking, and
humidity might swing nearly 100 percent. Clearly, swings like these
are not good for any seal - electrolytic capacitors or your Great
Aunt's jars of tomato jelly.
My advice is to use caution when getting NOS capacitors - research the
source, ask about date codes, and when you get them, inspect them,
margin test them, them burn them in.
--
Will
11:44 a.m.
New subject: Capacitors -- replacements?
On 12/11/2010 12:58 AM, Chuck Guzis wrote:
Nothing exact, but some pretty close-enough stuff.
How reliable are these NOS caps? They've got to be pretty old.
They may have to be re-formed, but I suspect they would not be dried
out.This gets you cap, that may have screw on terminals rather than a
PCB type mounting , which is what I suspect is used with this power supply.
--Chuck
Ben.
12:11 a.m.
New subject: Capacitors -- replacements?
On 2010 Dec 10, at 6:44 PM, Chuck Guzis wrote:
I've got a lovely old Lambda power supply here
(linear +/-15, +/-5)
that uses an old Sprague screw-mount (Computerlytic) capacitor. It's
rated at 34000uF, 15WVDC. It's all dried out, so it needs
replacement.
It looks as if it's going to be difficult to find a working exact
replacement.
What in your experience works best in these applications? Plain old
"snap in" electrolytics? Anyone have any hints on making the
replacement fit the larger footprint?
For mounting, how about:
a) Cut out a large hole in the bottom of the can, leaving some of it
for rigidity. Remove innards. Connect and stuff the new one in wrapped
with some plastic packing to fill up the extra space. Or cut or pry
open the seam at the top if you can leave enough metal to re-attach.
b) If the old cap is actually screw-mounted by it's terminals to the
PCB, and the new cap is small enough, again cut the can, but remove the
insulated top with screw terminals (discard the can), drill 2 holes in
it, zap strap the new cap to top and remount it on the PCB.
c) Less trouble: drill 2 holes or screw down a plastic mounting to the
chassis, to zap strap the new cap to.
3:14 p.m.
New subject: Capacitors -- replacements?
List,
I've got a lovely old Lambda power supply here (linear +/-15, +/-5)
that uses an old Sprague screw-mount (Computerlytic) capacitor. It's
rated at 34000uF, 15WVDC. It's all dried out, so it needs
replacement.
It looks as if it's going to be difficult to find a working exact
replacement.
What in your experience works best in these applications? Plain old
"snap in" electrolytics? Anyone have any hints on making the
replacement fit the larger footprint?
As you know, you should get aworking voltage at least as high as the
orignial (but some say that runnign an electrolytic way beolw its rated
voltage will shorten the life), and about the same value. For a 34000uF,
I would thinkthat 33000uF would be fine (these are not close-tolerance),
or 47000 uF.
Some of the vitage radio crowd open up the old electrolyitic can, extrac
the guts and replace them with the modern replacementment capacitors. I
susepct, though that your can is too small to do this (it's not old
enough to me much larger than the modern caps.). But you might be able to
make use of the plastic moulding/terminals.
Once when I needed a screw-terminal electrolytic, I soldered suitable
nuts ot the termianls of a PCB-mount ('snap in') part and then fixed it
in place with the original terminal screws.
-tony
4919
days inactive
4922
days old
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