PDP 11 gear finally moved

Tothwolf tothwolf at concentric.net
Mon Jul 20 21:03:59 CDT 2015

On Mon, 20 Jul 2015, Rich Alderson wrote:
> On Sat, 18 Jul 2015, Peter Coghlan wrote:
>> Rich Alderson <RichA at 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 electrolytic capacitors in power 
>>> supplies. The rest of the advice is sound.
>> Can you please clarify if this statement represents the policy of the 
>> Living Computer Museum or is it something more personal?  Perhaps some 
>> qualification or a re-phrasing would be useful as it does not appear to 
>> make sense as it stands?
> This is the policy of Living Computer Museum.  It is based on the 
> cumulative experience of multiple very senior electrical engineers[1] 
> doing restorations here, in conjunction with 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% of rating.


>> I think you may have seen or participated in some of the many 
>> discussions we have had on this topic on this list?  In light of these 
>> discussions, I find it hard to see how a categorical statement such as 
>> this one could be justified.
> Since the proponents of this practice make categorical statements with 
> no evidence that they want to listen to reasoned explanations, I long 
> ago gave over trying to convince them, and simply respond when someone 
> makes a statement to a newbie which will result in frustration and 
> failure for the unfortunate recipient of this advice.


Do you happen to have a list of whitepapers and/or links on hand? I too am 
getting tired of repeating the same thing over and over and compiling this 
sort of information in a single location might be helpful. Buried in my 
own archives I have quite a few papers and datasheets in pdf format, but 
they are all mixed in with everything else so finding them would be quite 
a challenge.

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