<story><title>Apollo Guidance Computer switching power supply works after 50 years</title><url>http://www.righto.com/2019/08/reliable-after-50-years-apollo-guidance.html</url></story><parent_chain></parent_chain><comment><author>userbinator</author><text>&lt;i&gt;We found that the capacitors were all in good shape with the proper capacitances. This is in contrast to modern capacitors, which often leak or fail after a few years. NASA used expensive aerospace-grade capacitors and X-rayed each one to test for faults, and this made a large difference.&lt;/i&gt;&lt;p&gt;That&amp;#x27;s also because these are hermetically sealed &lt;i&gt;wet tantalum&lt;/i&gt; caps, not the dry type that&amp;#x27;s notorious for shorting out and catching fire. &amp;quot;Wet tants&amp;quot; are &lt;i&gt;very&lt;/i&gt; expensive and you can still buy them today:&lt;p&gt;&lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;www.mouser.com&amp;#x2F;Vishay&amp;#x2F;Passive-Components&amp;#x2F;Capacitors&amp;#x2F;Tantalum-Capacitors&amp;#x2F;Tantalum-Capacitors-Wet&amp;#x2F;HE3-Series&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;www.mouser.com&amp;#x2F;Vishay&amp;#x2F;Passive-Components&amp;#x2F;Capacitors&amp;#x2F;...&lt;/a&gt;&lt;p&gt;&lt;i&gt;We were somewhat surprised that both power supplies worked flawlessly after 50 years.&lt;/i&gt;&lt;p&gt;I&amp;#x27;m not all that surprised, actually --- but perhaps that&amp;#x27;s because I&amp;#x27;ve seen plenty of videos on YouTube of more mundane equipment, like vehicles and appliances, coming back to life after several decades of storage or exposure to the elements with minimal repairs, so for a clearly high-reliability component like this AGC PSU to work is almost expected.</text></comment>
<story><title>Apollo Guidance Computer switching power supply works after 50 years</title><url>http://www.righto.com/2019/08/reliable-after-50-years-apollo-guidance.html</url></story><parent_chain></parent_chain><comment><author>jacquesm</author><text>That is beautiful work, the &lt;i&gt;welded&lt;/i&gt; connections are really impressive. Obviously they had to take into account massive forces, vibration and possibly impact damage, but still, to see components welded in place is something I&amp;#x27;ve never seen before, not even in very high end HF power electronics.&lt;p&gt;&amp;gt; The AGC that we&amp;#x27;re restoring belongs to a private owner who picked it up at a scrapyard in the 1970s after NASA scrapped it.&lt;p&gt;That is one lucky find. Imagine that it had &lt;i&gt;not&lt;/i&gt; been found and scrapped for its metal value. The mind boggles at the potential destruction of such a historical artifact.&lt;p&gt;&amp;gt; the cordwood components are mounted differently from the other cordwood modules.&lt;p&gt;For those from cities who have never seen cordwood:&lt;p&gt;Cordwood is a stack of wood of short length seen from the endgrain, typically used when referring to firewood but also sometimes used in construction.</text></comment>