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never used an oscilloscope but just got one

puffy09

puffy09

Active Member
All, I just picked up a tektronix 561A oscilloscope with type3A9 differential amplifiers in the inserts. It powers up although I have no test leads for it. Got it at GW for $10.00 . Will this unit be good for testing and trouble shooting? It has lots of cool tubes and looks sweet. Also was it worth the 10 dollars?
 
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You can get Velleman probes for $20 or so that are good enough for audio work. 'Scopes are the ultimate troubleshooting tool. Not familiar with that model, but Tek 'scopes have always been the gold standard.
 
Its probably set to X/Y mode if its just a dot.A very quick read on that site says you want to pull one of the diff amps out for standard display. With both in, it goes to XY mode, meaning one of the probes will produce a horizontal line and the other is your vertical. That mode has special uses, mostly with FM alignment and checking transmitters for symmetrical modulation output. It probably has other uses that I don't know about but thats what I've used it for.
 
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puffy09 said:
All, I just picked up a tektronix 561A oscilloscope with type3A9 differential amplifiers in the inserts. It powers up although I have no test leads for it. Got it at GW for $10.00 . Will this unit be good for testing and trouble shooting? It has lots of cool tubes and looks sweet. Also was it worth the 10 dollars?
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If you do not know anything about electronics it will be worthless to you. This equipment is used by electronics technicians and electrical engineers in the design, electrical measurement, evaluation, and troubleshooting of electronic circuits. There are also various measuring instruments for various other types of technical areas of specialization than can display their output on an oscilloscope.That's about all it's good for.

If this unit is in good working order, it was well worth $10 to someone who needs its capabilities. Depending on the specific requirements of the task at hand, that scope may be more than adequate or not sufficient at all. Audio is one of the least demanding applications where this kind of test equipment is used however, there are times when more capability is needed than a general purpose scope can provide. For example some scopes will display two or more channels of information at once. Others can store a display of a single event, that is capture it for study in the sense of a snapshot that can be viewed until the image is no longer needed. General purpose scopes can't perform those functions. Some applications require scopes that can display very high frequencies, much higher than general purpose scopes of the vacuum tube era could handle.
 
a friend was a techie in radio at kpfk, kppc,
and drake-chenault long ago. he used the 'scope to adjust the azimuth on tape heads, and he also ran stereo signals in to assure various parameters while recording at d-c.

we also ran the stereo signal in just to watch it. the more spacious recordings made a bigger display and were interesting to watch.

he also used it to make corrections for mono when fako stereo was on a disc.

there are so many things you can use one for other that the few items i mentioned, it just takes gaining the knowledge of how to use it and why.

it could force you into learning.
 
gadget73 said:
With both in, it goes to XY mode, meaning one of the probes will produce a horizontal line and the other is your vertical. That mode has special uses, mostly with FM alignment and checking transmitters for symmetrical modulation output. It probably has other uses that I don't know about but thats what I've used it for.
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X/Y mode is good just for fun. Connect left and right audio signals to the deflection amplifiers and adjust gain for the most interesting results. It's a bit like staring into a blaze in the fireplace. Much better than music video.
 
Please keep it coming

Please keep the info coming, I need all the help I can get . This site and all the persons on here rock. Learning everyday this is one of the best hobbies. It can possibly take a person that just enjoys music and with enough time and interest turn them into a closet electronics guru.
 
BinaryMike said:
X/Y mode is good just for fun. Connect left and right audio signals to the deflection amplifiers and adjust gain for the most interesting results. It's a bit like staring into a blaze in the fireplace. Much better than music video.
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There are several different music clips specifically written to generate neat patters on a scope in X-Y mode. Pretty cool to watch honestly.
 
My main use for a scope has been adjusting head azimuth on my open reel tape machines, mostly 3M Mincom, Otari and Ampex.

Cheers,

Otto
 
Until recently, I used a Philips PM-3231 dual-beam oscilloscope to monitor the left and right channel audio waveforms from my main stereo. Helped with troubleshooting channel imbalance and distortion issues, and also made for a really neat lightshow. Unfortunately, something burned out inside it recently. :sigh: Hoping to fix it sometime soon.

stereo_setup.jpg


I also have a Heath-Zenith 'scope from the '80s, a Hewlett-Packard 'scope from the '60s, and a couple of mini oscilloscopes which need work. Definitely handy to have around.
-Adam
 
The old Tek ‘scopes are great instruments. I have a 545 and love it. It hasn’t seen a cal lab for God-knows-how-long but is more than adequate for my needs.

Spend some time learning and becoming comfortable with it. You will find it to be an invaluable tool. Its uses are truly multitude.
 
Hint- keep the intensity low, especially with a slow moving spot, or you'll burn the phosphor in the tube, leaving permanent marks. Though I have faster and smaller scopes, I use a big old 545B for all my everyday work. You can't beat the crisp trace and flexible triggering options.
 
of course we have forgotten the included o'scopes in the marantz tuner and receivers. also, kenwood had a separate one for the stereo.

one important thing is the display should be off or dimmed when not being actively used as it will ruin the phosphors on the screen.
 
For $10 any old tube Tek scope had a few very desirable tubes in it... worth many times the asking price.
 
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