HP 3968A

[Jwalling]

Never seen one of these before, so I tried to find a manual out of curiosity. Nothing except for a mention in a bench brief from 1976.
http://www.ebay.com/itm/HP-3968A-Industrial-Data-Acquisition-Instrumentation-Reel-To-Reel-Tape-Recorder-/152660479131?hash=item238b460c9b:g:hmoAAOSwjIRZjof~

www.hparchive.com/Bench_Briefs/HP-Bench-Briefs-1976-09-12.pdf

Anyone have a pdf manual for this?

[alm]

Attached is a two-page excerpt from the 1980 HP catalog with technical specifications. These things were expensive (over $7k in 1980). I do not have a copy of the manual.

[Jwalling]

Attached is a two-page excerpt from the 1980 HP catalog with technical specifications. These things were expensive (over $7k in 1980). I do not have a copy of the manual.

Interesting, thanks. I guess I don't really understand what practical uses this device would have...

[alm]

Recording analog data for further analysis I imagine. For example, you might analyze the result on a scope or LF spectrum analyzer, or plot it on a piece of paper at a slower speed. Obviously bandwidth is limited to slightly beyond audio frequencies, but much better than a paper recorder or human writing frantically with a pencil .

This was before digital storage that was fast enough to keep up was common. The only fast alternative would be an analog storage scope, but that is limited to one screen full of data, and long-time storage is limited to Polaroids.

[wn1fju]

I have the HP 3964A, which is the 4-channel variant.  These are what they advertise - instrumentation recorders.  Used to acquire sensor data
such as voice, vibration, voltage, temperature, strain gauge, or whatever else you can think of.  Although the basic tape transport mechanism
is the same, these recorders were offered with different channel acquisition electronics.  There is the FM variant that goes down to DC, and the
direct record variant that doesn't (but it does go to 64 kHz on the high end).  My unit is packed with the FM cards. 

As is typical with 1970 HP stuff, it is built like a tank.  I only paid a few bucks for mine (I mean, who would really want one of these things?),
and it needed to have the pinch roller re-rubberized since it had turned into goop.

My biggest problem was finding adequate tape.  It was optimized for 3M888 tape, good luck!  I pieced together some old tape and at
least verified that everything worked correctly.  Old tape has a tendency to flake off and crud up the record head very quickly.  There are
some suggested tape restoration procedures that involve baking the tape for a while, but I didn't try that.

While I was in my "tape recorder" phase, I also managed to score a Racal 14DS 14-channel recorder.  Now there's a real beast.  And a while
later, that one developed problems with the oil-dampened tension arms, so I scored another one.  99 cents on eBay for that one (plus
shipping)!!!