Scope help.. How much voltage is too much?

I have a old heathkit tube oscilloscope. It is a model I0-17. I was wanting to learn a little about it and how to use it. My biggest question is how much voltage can a scope usually handle? This scope doesn't have any probes. Are there special probes for scopes that are different than those for multimeters?

My first project I want to use it for is trying to find where I'm getting a buzz in my stereo. It will buzz if my computer is hooked up to and it is grounded. If the computer is ungrounded it doesn't buzz. The stereo only has a two wire connector so it isn't groudned. I thought this scope could be usefull in tracking down where the buzzing is coming from.. Anyhow I need to know if I can plug this thing into the wall (120vac) or if it will blow up if I do that.

Reply to
Michael Kennedy
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Different strokes for different scopes. Some will only handle a few hundred volts before their front end will blow. Others, like Sencore analyzers, can handle 2000+ vdc/ac quite happily. Scope leads have important characteristics other than merely how much voltage they can safely handle -- such as capacitance. Also, there are multiplier probes which allow the user to measure higher-than-usual voltages with the same scope.

The manual for your scope ($22) can be found here:

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or here ($18):

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The manual is 60 pages, btw.

Try a device called a ground loop isolator. This may seem counterintuitive, since your stereo is not grounded, but isolators have been known to fix all sorts of seemingly weird grounding maladies. Don't be phased (pardon pun) by some online prices, as isolators can be had ultra cheaply; it's worth a shot.

Most any scope easily accomodates 120vac, but even if the spec'd max voltage is well above that, it's no guarantee yours won't "blow up". Yours is afterall an OLD scope, which no doubt hasn't been checked for 100% functionality, safety and calibration in quite some time.

Reply to
Ray L. Volts

As for the hum, have you tried connecting bot stereo and computer to the same wall outlet or power bar? Sounds like ground loop to me, and if so, this should make it go away.

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Reply to
tempus fugit

The issue is solved by a ground loop isolator but when I run input in to my vcr I also get bars on the screen. I think I have a grounding issue in the building. The voltage spikes when the AC on the other leg of 120v starts up. It is not a 240v ac it is on a seperate circuit on a seperate leg. I would call it a sperate phaze, but it is really just off a different tap on the transformer on the power pole. Anyway I'm going in to too much detail. I'm sure you know what I mean. I think I may need to drive another grounding rod.

Reply to
Michael Kennedy

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