Author Topic: Where to start with an HP 1720A oscope?  (Read 503 times)

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Offline orngnr

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Where to start with an HP 1720A oscope?
« on: April 19, 2018, 09:17:43 am »
I have an old HP 1720A oscilloscope. I'm not sure if my mind is going empty, but I can't get even a DC signal to show up on either channel. All I've got is a horizontal line that I can't get to move up or down, or change no matter what my inputs are. I don't think the unit is broken just yet, more likely I'm missing something simple about these older scopes. Any ideas?
 

Offline edavid

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Re: Where to start with an HP 1720A oscope?
« Reply #1 on: April 19, 2018, 09:26:15 am »
1. Read the Tektronix tutorial "XYZs of Oscilloscopes": http://ecelabs.njit.edu/student_resources/XYZ-Scope.pdf

2. If you still can't get it to display anything, post a clear picture of the front panel so we can see how all the controls are set.
 

Offline orngnr

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Re: Where to start with an HP 1720A oscope?
« Reply #2 on: April 19, 2018, 11:03:21 am »
Thanks for the tutorial, helped me brush up on some topics I'd forgotten about. I'm able to get a signal displayed now, which is great.

Now, it's sweeping really slowly. I think this is a characteristic of an analog scope I'm not used to. Do you know how I can speed up the sweep so that it can show the 10 Hz square wave reliably?

Here's a video of what it's doing now.
https://youtu.be/0xijk8Gf32A
 

Offline edavid

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Re: Where to start with an HP 1720A oscope?
« Reply #3 on: April 19, 2018, 11:21:42 am »
1. That is too low resolution to see how the controls are set

2. You need to adjust the time/div knob

3. It's going to be hard to view a 10Hz square wave on an analog scope... try 1kHz
 

Online vk6zgo

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Re: Where to start with an HP 1720A oscope?
« Reply #4 on: April 19, 2018, 05:24:28 pm »
(1)It isn't triggered.

(2)"Focus" is not set correctly.

A reasonable analog Oscilloscope should be able to display 10Hz, but it would be easier to trigger at 1kHz.
 


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