Oscilloscope Adapter for CRT Television/Monitor?

[Pionerfa]

Hi - new to the site and hope I'm posting a thread in the right place!

Is there such a thing as an adaptor can be plugged into the co-ax socket of an old CRT TV, as an old video game might have been, so that oscilloscope-like waves can be watched on screen (synched with audio)?

I really like Pioneer SD-1000 and SD-1100 Stereo Scopes, but they are outside my budget. So I'd like something that will respond like an oscilloscope does to music played through a hi-fi. I don't require an accurate 'oscilloscope proper', just something interesting to look at.

I've seen some YouTube uploads of 'hacked' CRT televisions turned on their sides, with their wiring tapped-into. But I don't want to do that. And wonder if some kind of converter was ever - or is - available to produce oscilloscope-like lines on a TV?

Alternative afterthought: I notice a number of inexpensive NOS oscilloscope CRTs on eBay. Are sensibly-priced (less than 150 pounds, euros or USD) driver boards available for these oscilloscope CRTs which can be triggered by music?

Thanks for reading this.

 

[dr pepper]

There are some arduino projects online that are an oscilloscope with a video out, this wont work with a coax antenna i/p, but it would work on a video in or a scart connector, and it would require some building work.

 

[unclejed613]

when i was young, i had a collection of various TVs. i had one TV with a bad tuner that i would experiment with. in one such experiment i removed the deflection yoke from the neck of the tube (but kept it wired to the chassis so the TV still produced HV). i put a spare yoke i had onto the tube, and fed the deflection coils with audio amplifiers, and it would produce lissajous patterns. since the deflection yoke was magnetic, the frequency response was limited to audio frequencies, but it was fun to experiment with it.

 

[crutschow]

You should be able to disconnect the vertical deflection circuit (leaving the horizontal circuit intact) and drive the vertical coils with an audio amp.
I think currents on the order of an amp should give a significant vertical deflection.
Since the horizontal deflection frequency is around 15kHz, a 1kHz audio signal will display about 15 cycles.
(Note to be sure to turn the brightness down before you do that, otherwise you will likely burn a horizontal line in the phosphor.)

Alternately, If you had a circuit diagram of the TV, you might be able to disconnect the vertical oscillator circuit and input a signal into the vertical driver stage.

Here's a paper on vertical deflection circuits that may be of some help.

 

[Nigel Goodwin]

Driving the scan coil makes for a VERY poor scope, assuming you wanted to make a scope out of a TV?, then you essentially build a complete modern digital scope, without the LCD display, Then instead of writing the contents of the memory to an LCD screen, you write them to the display buffer of a video 'card' that outputs a TV compatible display. Years ago there were a couple of books about making cheap video display systems using micro-processors (The Cheap Video Cookbook - if I recall correctly?)

I can't spot those on archive.org, but there is this one (TV Typewriter Cookbook):

https://ia902309.us.archive.org/17/items/tvtcb_doc/tvtcb.pdf

 

[dr pepper]

The OP doesnt want to mod their telly.
I have converted a Tv into a vector monitor, rewinding the yoke, and yes its tricky to get reasonable response out of them.

 

[unclejed613]

Driving the scan coil makes for a VERY poor scope, assuming you wanted to make a scope out of a TV?

Tektronix made vector displays using magnetic deflection. originally they were used for military radar systems, but some early arcade video games (Asteroids and Omega Race) used vector graphics. Tektronix made all of the vector graphic displays and computer terminals used in the original Battlestar Galactica TV series.

 

[crutschow]

Driving the scan coil makes for a VERY poor scope

True.
But the TS stated:

So I'd like something that will respond like an oscilloscope does to music played through a hi-fi. I don't require an accurate 'oscilloscope proper', just something interesting to look at.

So I think simply driving the vertical deflection coil may work sufficiently for his purposes.

 

[Nigel Goodwin]

True.
But the TS stated:
So I think simply driving the vertical deflection coil may work sufficiently for his purposes.

Except he specifically stated he didn't want to mess with the TV, but simply plug in the aerial socket.

 

[ChrisP58]

Do you specifically want to use a CRT television? Or just achieve that visual affect?

If the latter, then I would suggest using one of the many soundcard oscilloscope software utilities to repurpose an old computer to do the same thing.

Googling "soundcard oscilloscope software" should bring up lots of options.