20 Aug
2015
20 Aug
'15
3 a.m.
On 2015-Aug-19, at 3:58 PM, William Donzelli wrote:
Yes, let the guys keep selling the higher demand
documents - HP, Tek,
Heathkit. Nearly all of those are super common anyway
. . .
In fact, due to your time constraints, I would not bother with the HP,
Tek, or Heathkit manuals at all
. . .
Not to disagree or contradict you, but I have to mention what may be an exception to that
in the case of one HP instrument:
I have an HP 5480A "Digital Signal Analyser" from ca. 1968.
This instrument might be the first DSO (Digital Sampling Oscilloscope), although as
intended it's a little more more than a DSO in that it does averaging over repetitions
of the signal to take out noise. It also has a couple of other modes to collect and plot
frequency histograms and such. It's limited to 50KHz bandwidth given it's era, but
it comprises input amps, ADC, 1K*24bits of core memory, ALU, a couple of DACs, CRT
display, timebase, and a hardwired control system.
It's an unusual and interesting instrument for it's time and I've kept it
around (I acquired it 12 years ago) as another early example of the transition from the
analog world to the digital world.
It would have been phenomenally expensive in its day, and targeted at a limited and
specialised market, so I doubt the production was very high.
The operating manual has turned up on the web recently (hparchive.com, I couldn't find
anything when I first acquired it), which has been most useful to just figuring out what
it does and how to use it.
It seems to have some intermittent fault in the acquisition/capture control however.
I've reverse engineered maybe a third of it, but the remainder is still a large number
of SSI TTL ICs and a whack of wiring, and I'd be happy to see a service manual show up
instead of doing the remaining two thirds.