[R-390] HP 8640B Question

[Mahlon Haunschild]

Barry,

Any 8640B counter will display all zeroes if its input is inadvertently 
switched to the front panel external counter input connector (this is 
easily overlooked; I've done it myself several times).

Were you thinking of something else?

By the way... while writing this I turned around to my equipment rack 
and switched on my two 8640Bs which I hadn't turned on in a very long 
time (at least a year).  The freq. displays are within .005% of where I 
left them and the PLLs lock right up as they should.  I'll keep 'em.

regards,

Mahlon - K4OQ
> ------------------------------------------------------------------------
> 
> Subject: Re: [R-390] HP 8640B Question
> From: "Barry" <n4buq at knology.net>
> Date: Sat, 20 Feb 2010 10:46:03 -0600
> To: <r-390 at mailman.qth.net>, "2002tii" <bmw2002tii at nerdshack.com>
> To: <r-390 at mailman.qth.net>, "2002tii" <bmw2002tii at nerdshack.com>
> 
> 
> I'm curious about something.  Many of the 8640Bs I see display all zeros 
> - apparently on start-up.  Some of the ads state the display simply 
> shows all zeros - apparently even when the frequency change knob is 
> exercised.  Is this a common?  Is there something one has to do to get 
> the frequency to display?
> 
> Thanks!
> Barry - N4BUQ