[R-390] maintenance

[Richard Loken]

Re: tube life.

Years ago, when I was younger, stronger, and happier I did broadcast
maintenance and I remember working on a McCurdy audio mixing console that
contained many small modules which each contained two or three single
ended metal octal tubes.  It was my experiance that the console would run
without apparant degradation until the tubes were absolutely flat, we did
not PM the console but rather fixed it when it broke which was less than
once a year and then we would replace one or two totally dead tubes.  I
was always impressed with that console - so conservatively designed that
individual tube characteristics were pretty much irrelivant.

If we PMed those consoles we would have purchased hundred tubes to replace
hundreds of apparantly failed tubes to restore performance whose absense
was never noticed.  Good for tube sales I'm sure.

-- 
   Richard Loken VE6BSV, Systems Programmer - VMS  : "Anybody can be a father
   Athabasca University                            :  but you have to earn
   Athabasca, Alberta Canada                       :  the title of 'daddy'"
   ** richardlo at admin.athabascau.ca **             :  - Lynn Johnston