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It is alive! Mu-ha-ha-ha!

PostPosted: Fri Nov 10, 2017 6:09 am
by Cheb
For 17 years! 17 years I couldn't use it because its power cord was torn off and I was too lazy to make it another one.

But finally! After much soldering and nerve-wracking moment of thinking I'd accidentally set it to 115V and all was lost - this ancient beast comes to life!!!

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Eerie violet glow from the gas discharge voltage stabilizer:
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I even have a copy of the writing-off act. Reason: 100% wear :mrgreen:

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Note: it does contain several "semiconductor triodes" as they are called in the manual, generating stabilized -24V used, among other things, to drive heaters of the Y-amplifier tubes :shock:

Earlier: the smothering embrace of dust.
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Re: It is alive! Mu-ha-ha-ha!

PostPosted: Fri Nov 10, 2017 12:44 pm
by Ellen Kuhfeld
I've seen older. I've used older. But that still is one troglodyte piece of -- oscilloscope?

Re: It is alive! Mu-ha-ha-ha!

PostPosted: Fri Nov 10, 2017 12:51 pm
by Cheb
Yup, an oscilloscope :D Made in 1970, with some tubes dating 1968.
With a built-in 1kHz generator of sample voltage (square form, 10mV..100V).

Not only it works, it's a vital piece in my master plan of creating an ATX power supply by hand :twisted: One that works from 20..30V DC (battery) directly, without galvanic isolation. Just think of the efficiency! :roll:

Re: It is alive! Mu-ha-ha-ha!

PostPosted: Fri Nov 10, 2017 5:06 pm
by Dumbledork
The most advanced electronics related stuff I can do is changing a light bulb.

Re: It is alive! Mu-ha-ha-ha!

PostPosted: Fri Nov 10, 2017 9:10 pm
by Spica75
Cheb wrote:Yup, an oscilloscope :D Made in 1970, with some tubes dating 1968.
With a built-in 1kHz generator of sample voltage (square form, 10mV..100V).

Not only it works, it's a vital piece in my master plan of creating an ATX power supply by hand :twisted: One that works from 20..30V DC (battery) directly, without galvanic isolation. Just think of the efficiency! :roll:


:mrgreen:

Sounds fun.

My eldest brother had one of "those", bought sometime in the 80s, much smaller and with slightly fewer settings though.
He used it to design some circuitboards and play around with some computers(and connect it to various electronics to do weird shit noone else had a clue what or even why he was doing it).

Re: It is alive! Mu-ha-ha-ha!

PostPosted: Sat Nov 11, 2017 7:48 am
by Cheb
The most advanced electronics related stuff I can do is changing a light bulb.

That is useful too.
Basically, this thing lets you see what is really going on in the circuit by plotting a graph of voltage changing over time. Quite similar to CRT TVs in that the beam scans horizontally at constant speed, then jumps back to the left. What is different, though, is that vertical position of the beam is driven by input signal and the rate of scan could be varied in very wide margins (from 10 seconds to 10 microseconds, in this case) and is synced to the input signal. This is *much* faster than a TV could move its beam, so CRT oscilloscopes used electrostatic plates instead of magnetic coils to drive the beam. The tube also has much lower voltage than the TVs, and much less brightness, only enough for one relatively bright line.
Of course modern oscilloscopes are just mini-computers with specialized input hardware to capture voltage graphs.

bought sometime in the 80s, much smaller

It seems that the transition from 70s to 80s brought much smaller, shorter CRTs. Oscilloscopes just a decade younger are all compact things with small square screens.

and with slightly fewer settings though.

This one is designed to do many extra tricks. It provides reference signal for calibration so that you can use it as as a quite precise voltmeter. It supports plates driven by external source or shorted (the chicken beak handles at the top corners). It supports synchronizing from an external source separate from the input signal, and it supports brightness modulation by external source.
Not to mention it has DC input (meaning you can measure constant voltage with it) which is quite a feat for a tube amplifier.

He used it to design some circuitboards and play around with some computers

Hell yeah! :twisted:

P.S. Of course with oscilloscope prices beginning at $300 and just one pet project planned where I *really* need one, this old beast is a life-saver.

Re: It is alive! Mu-ha-ha-ha!

PostPosted: Tue Nov 21, 2017 6:27 am
by Sunshine Temple
Well, dang. That's an impressive old beast of a 'scope right there.

Re: It is alive! Mu-ha-ha-ha!

PostPosted: Tue Nov 21, 2017 1:32 pm
by Té Rowan
Ellen Kuhfeld wrote:I've seen older. I've used older. But that still is one troglodyte piece of -- oscilloscope?

A Danish magazine published — in the 1980s! — a series of articles on building a valved oscilloscope. The top end wasn’t super-impressive; one or five (can’t remember which) MHz on the Y input. Still, it left a bloke with That Itch…