Off-topic, but interesting (Fiorina fired)

[Philip Pemberton]

In message <16908.50818.183000.43528 at gargle.gargle.HOWL>
          Paul Koning <pkoning at equallogic.com> wrote:

> ...until one of those tubes loses it vacuum and you find it's either
> unobtainable or costs $75 or more.
> 
> That happened with my 535 and its high voltage rectifier tube (5865?
> Something like that).

Ouch. And I thought the hybrid modules for the 466 were expensive (I've seen
them go for anywhere between $50 and $200).

> I now have a 7603, which is quite nice.  A lot lighter than the 535,
> and it has a useful bandwidth for ham radio purposes.  Now if only I
> could find a spectrum analyzer plugin for it that costs less than a
> car... :-)

I was going to build a spectrum analyser addon for my 466, until I started
trying to work out how to actually design one... I've never really been good
at analog electronic design :-/
I did, however, do some work on building a primitive computer-based
oscilloscope. Two RAMs, two high speed binary counters, two A/D converters, a
clock generator, an inverter and some little bits to add a PC interface.
Unfortunately the high speed counter and RAM chips went obsolete just as I
finished the design work on it, but not before I'd bought the A/D converter
ICs :(

At the moment I'm building an 8-channel logic analyser. Finding the parts for
the acquisition circuitry is proving troublesome (basically a FIFO or a
cache RAM chip from an old 386/486/Pentium motherboard and a counter). After
that, I get to play around with the triggering circuitry. Yay.

Later.
-- 
Phil.                              | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
philpem at philpem.me.uk              | ViewFinder, 10BaseT Ethernet, 2-slice,
http://www.philpem.me.uk/          | 48xCD, ARCINv6c IDE, SCSI
... I can't believe my computer's on fire.