Information re HP1722B Scope

[Aussie Susan]

(Originally added to the Datasheets/Parts forum several days ago but no responses - hoping for better luck here)

I recently bought an HP1722B scope that only had a photocopied manual that described the internal circuitry and listed the various controls and adjustments.

I've been away from such things for (quite) a few years and, while I'm familiar with using scopes in general, this one has a digital readout and associated controls that seem to indicate that it can be used for time interval measurements which I could use (if that is the case)

My problem is that I have no idea how to use these controls and general "playing" has not resulted in anything other than "all zeros" in the digital readout.

Does anyone have any documentation that would tell me what the controls (other than the standard sweep rate and channel amplification controls) are for and how to use them?

Thanks

Susan

(I'm sorry but I'm writing this at work and so I can't recall the labels on the controls - I'm hoping that someone knows this type of scope and can help me. I can add other details later when I get home if necessary))

 

[crutschow]

I believe the readout is used in conjunction with the cursor controls to perform measurements. You move the cursor(s) to the portion of the waveform you want to measure and the digital readout will display the measurement. It possibly may be used to measure either voltage or time, I'm not sure.

If you post the control labels, I may be able to be more specific.

 

[Aussie Susan]

Sorry for the delay - today is a holiday here and so I can sit with the CRO next to me as I type this in.

There is an area in the top-right-hand corner that has a grey background with a BNC connector labelled "Ext trig", next to a knob and 3 spring-loaded 3-way switches that are mounted horizontally with a marking around them of "Time Interval" and individual labels of "Delay" (the known) and "Coarse" "Med" and "Fine" ("Dec" to the left and "Inc" to the right) for the switches. Below the switches is another knob labeled "Trig Level" that has a far-left switch position marked "Starts after delay".

The above forms the top and right-hand bounds of an enclosed rectangle that has the items I originally asked about with a Label of "Chan A" and "Interval" on either side of (what looks like) a momentary contact pushbutton labeled "(Ref Set)". Below these are two yellow (to the left) and 2 blue (to the right) push-in/push-out buttons labeled (left to right) "Posn", "Input", "Time" and "1/Time" above the buttons and "Cal Volts Uncal %", "DC Volts", "Sec" and "1/Sec" underneath.

Below the buttons is the digital readout I mentioned.

To the left of these is a vertical row of push on/push off buttons that are labelled (from the top within the greyed section that seems to be part of the one mentioned at the beginning of this message) "Ext <divide sign> 10", "Int"/"Ext", "AC"/"DC", "LF Rej", "HF Rej" and "+"/"-". There is a marking jammed next to these with "DLY'D TRIG'G" which I think corresponds to similarly marked controls further down the scope that are marked "Main Triggering".

In general I can understand the controls as they relate to a "normal" dual-trace scope, but the ones in the top-right corner have me stumped.

I guess what I'm really after is legible copy of the manual (PDF would be ideal) that explains what all of the controls are and how they should be used. (I've tried looking on the net but the only sites that come up look very suspicious and either want too many details or money to join).

Thanks

Susan

 

[crutschow]

I did a short search and also could not find a manual for that 'scope. You may just have to wing it. (Anyway haven't you heard the joke that "real engineers" don't need a manual?).

The best I can suggest is that you play with the controls described in your third paragraph which are above the digital readout.

The "Time" likely refers to the measurement of time intervals and the "1/Time" converts the interval to frequency.
Similarly the various "...Volts" buttons likely are for the measurement of voltage on the 'scope display.
"Ref Set" likely refers to setting a reference point on the screen for the measurements.
The "Chan A" label would imply that the measurements only apply to Channel A.
I would think there should be some combination of the buttons that will generate a cursor (or pair of cursors) on the screen that you can then be moved to make a measurement of a displayed waveform.

Good Luck,

Edit: I found this old magazine which has an ad for the HP1722 that refers to a "two-dot" measurement system in conjunction with the "dual delayed sweep" capability of the 'scope. So it apparently just places dots on the screen, not a cursor as I had previously thought.

 

[Aussie Susan]

Carl,

Thank you for your comments and for the magazine reference. I've printed them both out and I'll have a "play" (when I get some of that elusive "spare time" - Ha)

As for being a "real engineer", I'm not like Dilbert - I don't seem to have "the knack". Also it is a long time since I've been "engineering" although I still use all of the principles (suitably abstracted) I learned at University.

But sometimes, you just want to get the most out of your gear and (unlike the stereotypical male) I can and read a map - and a manual - because it is faster than "trial and error".

Susan

 

[crutschow]

Well, unlike the joke, I do also read manuals of even simple devices, since I often find information about it that is not apparent from casual experimentation. But if you don't have a manual then all you can do is poke and prod the buttons and knobs until you find the right combination that works. There's usually some logic behind how it works, it just may be difficult trying to determine what that is. Sort of like trying to set the time on a digital watch without the instructions. Of course any 10 year old kid who's played video games all his life is probably a lot better at that then we are.