[Eric Adams]

Hi Guys,
It looks like I'm going to get a scope for a great price at a local sale. Since I've always wanted one, I have to have it. My question is (don't laugh) Why do I need it? What will it do for me on tube radios?

Thanks,
Eric

[Eric T]

Probably the best use is for signal tracing if you need to troubleshoot a problem. You can also use it for finding internal noise sources or clipped audio signals, etc.

I have an older 50mHz crt scope for personal use, but I also have a decent portable digital scope for work that I also use during alignments because it's got an accurate frequency counter to set the old signal generator with.

[Eric Adams]

Thanks Eric,

That gives me a reason! Now I guess I'll find some info on just how to use it.

Eric

[Arran]

An oscilloscope is one of those nice things to have but it isn't really something you need to have to work on old radios of the 1930s. I have about three of them, I think all three were given to me from various sources, and I don't think I have used any of them since I don't really play with vintage TVs or FM sets that much. Mostly what I use is a signal generator, and from time to time I calibrate it with a borrowed frequency counter. I think part of the reason they were given to me is much the same reason they sit collecting dust in my possession, they just don't get used much.
Regards
Arran

[AI2V]

Here's a mandatory course for oscilloscope instruction: http://www.njarc.org/scopes4dopes/

My scope is used daily in troubleshooting; it allows me to "see" what kind of signal is riding on my screen supply, how much ripple is in the supplies, signal levels, and very importantly, audio distortion.

You will be needing a pair of probes, preferably the kind that is switchable from 1:1 to 10:1 divider. The purpose of the 10:1 divider is not necessarily for the dividing function but more as very high impedance that won't load down the circuit under test. They are quite inexpensive on Ebay.

[Eric Adams]

Great. I'll check them out on ebay. Do you always have to use a probe?

Thanks,
Eric

[morzh]

A scope is not necessary. But highly desirable.
But not necessary

[Arran]

I've never bothered using one on an old AM only radio mostly because if there is ripple, distortion, or any other problem, 90% of the time drifted resistors and bad capacitors are to blame, and maybe a tube problem another 5% of the time, the rest is more obscure stuff like bad mica caps and open coils. So I try powering a set up on a variac, if it looks safe to do so, and then see what it does if anything, then I start changing any old capacitors or drifted resistors I find, I also check the various coils for continuity. If the set doesn't work after the rebuild then I start troubleshooting, checking voltages and so forth. I don't doubt that an oscilloscope can be useful on a stubborn set, but I end up using a capacitor checker and variac much more on these old beasts. I've never gone out of my way to acquire an old scope where I actually had to pay money for it. But if you work on old TV sets and FM radios an oscilloscope is pretty well a necessity for alignment.
Regards
Arran

[codefox1]

Darg my old Leader scope occasionally to see when sine starts to distort against a non inductive loads when working on amps. Modest digital meters can measure AC ripple over DC supplies, and a few other things. Agree, great for alignment help and a couple of other things, and great to show kids what their voice looks like. For AM set restoration, probably last piece on your bench.

[TA Forbes]

I set my scope display on 60 Hz sine wave and use it to mesmerize my cats.

[Eric T]

Eric, an oscilloscope is virtually useless without at least one probe.

[Chuck Schwark]

I've been in the tv, electronic and broadcast tv field for 40 years now,
and I always have had a scope handy for anything.

The vintage, working TEK 475 w/DM44 on a cart is my
"go-to" test instrument.
Also have a TEK 2465 for digital stuff too.

"Grew up" in the industry with a scope by my side and I'm partial to it.

:-)

Happy New Year to All,

Chuck

[Eric Adams]

Thanks everyone. And Happy New Year. I just got the scope for $5.50. I was the high bid!
Pete, I've started to go through the course. Very informative. Hopefully I'll learn why I bought it. Although for that price I could just put it on my bench and look cool!

Eric

[Eric T]

Decades ago, when I was in Navy Electronics school, we hooked up an o-scope to a radar system output and watched the radar sweep right there on the o-scope. I had seen my dad use a scope many times, but never suspected you could do something like that with one.