[volt-nuts] What made a HP3458A so expensive

[Bill Gold]

I did have a display that was going dim on one digit so I ordered a new VFD
display from Agilent, not the whole board just the actual display.  When I
compared it to the original I found that the top to bottom distance between
the pins was larger than the original display.  So I had to carefully bend
the pins inwards towards the center until the distance was correct.  Imagine
a DIP IC with a 0.6 inch distance being reduced to a 0.5 inch distance.
Fortunately the pitch from pin to pin in the rows was the same.

There are 56 pins on this sucker and bending them inwards and then getting
them into the 56 holes on the PC Board was a real trick but it can be done
with a great deal of patience.  I never did question Agilent if they had
changed the PCB in later models to accomodate this change.  The new VFD was
a Noritake just like the old one.  The distance on the old one was 1.375"
and the new one 1.5".  I don't remember if the part number was different.
Since this is a very custom display made expressely for Agilent you would
have thought that they would have kept the dimensions the same on the pins.
Once I got done the display worked perfectly which was a big relief.

In looking at the Agilent site it looks like these might have already become
unobtainium but there is a repair service available and a PCB exchange.  My
guess would be that because of the size difference they want to do the
repair work themselves.

----- Original Message ----- 
From: "Mark Sims" <holrum at hotmail.com>
To: <volt-nuts at febo.com>
Sent: Saturday, January 18, 2014 9:55 AM
Subject: [volt-nuts] What made a HP3458A so expensive


> One problem with leaving the 3458A on all the time is the vacuum
fluorescent display.  These have a rather limited lifetime and leaving them
on 24/7 puts a lot of hours on the tube.  Someday those displays will become
unobtainium...
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