15 Aug
2005
15 Aug
'05
5:31 p.m.
From: "Joe R." <rigdonj at cfl.rr.com>
At 03:51 PM 8/12/05 -0600, you wrote:
Hi
From what I've been told, WD-40 contains both silicon and
petrolium oils. I prefer using silicon grease for this purpose.
Past experiments with petrolium oil and grease showed that the
contact resistance increased on clean contacts while the
silicon grease showed a significant drop in resistance.
I recommend Dow-Cornings, DC-4.
Dwight
On 8/12/05, Brad Parker <brad at
heeltoe.com> wrote:
I've had similar trouble with the HP 1000 boards. I found that if I
clean the edge connectors and them wipe them with a rag slightly dampened
with WD-40 (mostly kerosene, a light oil) that the cards go in and out much
easier and I have a lot less intermitant contacts. I believe the oil
coating also helps reduce oxidation of the contacts.
Joe Is there a list of the various pdp-11 unibus
backplanes anywhere?
I do not know of a master list online.
My 11/44 has a DD11-DF in it which is impossible
to get cards into and
out of. It's like something is physcally wrong with it. Rather than
damage any cards I thought I'd replace it.
It takes a bit of force to get hex cards in a nearly-unused backplane.
I've bent latches trying to get boards in. 
15 Aug
15 Aug
2:16 p.m.
At 02:31 PM 8/15/05 -0700, Dwight wrote:
Does DC-4 lower the force required to insert and remove the board? Where
can you get it? Any idea how much WD-40 increases the contact resistance?
Even if it does increase the resistance it has cured many of problems that
I've had with the 1000s so it seems to do more good than harm.
Joe
From: "Joe
R." <rigdonj at cfl.rr.com>
At 03:51 PM 8/12/05 -0600, you wrote:
Hi
From what I've been told, WD-40 contains both silicon and
petrolium oils. I prefer using silicon grease for this purpose.
Past experiments with petrolium oil and grease showed that the
contact resistance increased on clean contacts while the
silicon grease showed a significant drop in resistance.
I recommend Dow-Cornings, DC-4. On 8/12/05, Brad Parker <brad at
heeltoe.com> wrote:
I've had similar trouble with the HP 1000 boards. I found that if I
clean the edge connectors and them wipe them with a rag slightly dampened
with WD-40 (mostly kerosene, a light oil) that the cards go in and out much
easier and I have a lot less intermitant contacts. I believe the oil
coating also helps reduce oxidation of the contacts.
Joe Is there a list of the various pdp-11 unibus
backplanes anywhere?
I do not know of a master list online.
My 11/44 has a DD11-DF in it which is impossible
to get cards into and
out of. It's like something is physcally wrong with it. Rather than
damage any cards I thought I'd replace it.
It takes a bit of force to get hex cards in a nearly-unused backplane.
I've bent latches trying to get boards in. 
7:31 p.m.
Someone wrote....
>>>> My 11/44 has a DD11-DF in it which is
impossible to get cards into and
>>>> out of. It's like something is physcally wrong with it. Rather
than
>>>> damage any cards I thought I'd replace it.
That's not
totally uncommon, many of my DEC machines exhibit this even after
much care in the backplane restoration. Non-Hex Unibus cards also seem to
rock back and forth slightly in the slots, something I think is not good
design.
Someone else wrote...
>> I've had similar trouble with the HP
1000 boards.
Now that's unusual, at least to me. There's been quite a large
number of HP
1000's make it in and out of my place. I can only think of one or two that
had problems like this and the problem was normally 3rd party cards.
I found that if I
>>clean the edge connectors and them wipe them with a rag slightly dampened
>>with WD-40 (mostly kerosene, a light oil) that the cards go in and out
>>much
>>easier and I have a lot less intermitant contacts. I believe the oil
>>coating also helps reduce oxidation of the contacts.
Ugg... I wouldn't
suggest WD-40. It's not helpful to some other things
commonly on circuit cards.
Please please please buy a can of Caig Pro-Gold for use on gold edge cards
and directly on gold pin backplanes. I promise you'll be extremely happy
with the results which are both instantaneous, extremely effective, and last
a long long time.
Jay West
6911
days inactive
6911
days old
2 comments
3 participants
participants (3)
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dwight.elvey＠amd.com -
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rigdonj＠cfl.rr.com