Yeah, you haven't lived till you've been knocked on your kiester by a second anode lead.

Double so when it results in a dropped tube!

Best regards
HP

 

It may not be precise but the modification can give a person the general visual wave form. Useful for someone who has an old TV sitting around (and a little bit of time) but no oscilloscope. I fall into that category at the moment!

Vertical input comprised of spectrally pure (i.e. sinusoidal) ELF through AF signals may render a tolerably faithful display...

 

True! Graphite is an interesting thing. Today after waking up (this is my last day off from work this week) I was bored and trying to get the sleep out of my eyes. So I picked up a pencil and doodled a few thick lines on an envelope and placed a 9v battery upside down on the doodle lines. Then I pulled an LED from my part drawer and touched it to the graphite doodle lines while still trying to get the sleep out of my eyes. Old trick but when the LED lit up a bit of sleep left my eyes and I began to feel the wonder of the world I felt when I was much younger than I am today. Encase that stuff in a vacuum and you could run into trouble for sure!

I always demonstrate to my students the pencil lead potentiometer. I just draw a very thick dark line across a sheet of paper and then measure the resistance with a VTVM (a good old analog meter is more impressive). As you move the probe along the line, the resistance changes. Lots of OOhs and Ahhs from ny rapt students.

 

why do you want to mess with old CRT?

You can get small LCD video displays.
You can get adapters for VGA flat panels, video to VGA.

These CRTs are just immobile monsters belonging to a different era.

Extracting parts? Waste of time. You can buy NOS parts by weight at some places,
then rummage through them for days and see what you got.

 

Extracting parts? Waste of time..

I agree about 90%, but not completely. Desoldering is a useful skill and one can get a lot of practice. You can also learn to identify many different parts. And there are a few parts worth grabbing, in my opinion, if you think you might need them for hobby projects, especially high voltage transistors.

If you already know how to desolder and identify parts, and you're building larger projects instead of just experimenting, then an old TV is just a nuisance. Where I live, you have to pay to have them taken away.

 

I agree about 90%, but not completely. Desoldering is a useful skill and one can get a lot of practice. You can also learn to identify many different parts. And there are a few parts worth grabbing, in my opinion, if you think you might need them for hobby projects, especially high voltage transistors.

If you already know how to desolder and identify parts, and you're building larger projects instead of just experimenting, then an old TV is just a nuisance. Where I live, you have to pay to have them taken away.

But its toxic too, and what about the remains?

 

Owing to the nonlinear and, in fact, near discontinuous frequency response inherent to magnetic deflection schemes, such do not lend themselves to anything approaching 'faithful' oscillography . --- That said, such a device could make an appealing 'light show' display if fed, for instance, with an audio signal

!

That's why most people do like the Elektor project and build an add on box that modulates a video signal to produce a facsimilie of the waveform on the existing raster-scan.

You can also make a UHF spectrum analyser out of an old TV - the vertical sawtooth is dimensioned to 30V and fed to the tuning varicap, a comparator compares the AGC voltage with a sample of the 30V sawtooth to determine at what point on the scan the beam is turned on or off.

 

Some old technologies take 2 decades to disappear, others from one year to the other (mostly because theres no advantage to keep using them).

The number of people dealing with the technology becomes smaller and smaller progressively.
But you can still find old 8 bit CPUs, lamps, 50 Hz transformers, valves, nixie tubes and so on.

 

Double so when it results in a dropped tube!

Best regards
HP

My very first TV eventually developed EHT rectifier problems - the number had rubbed off so I got an EY87 replacement when it should've been a DY87, so the problems persisted until the error was pointed out.

Even with plenty of practice, it took me a while to remember that the CRT final anode was connected to the EHT rectifier cathode (and valve socket) - this resulted in me "manually" discharging the final anode capacitance a few times.

 

These TVs are probably at least 30 years old, there is nothing useful in these big dusty old boxes and the TS is talking about collecting 8 of them! Remember, the TS has no electronics experience so all this talk of utilising the high-voltage stuff or building an oscilloscope is irrelevant and potentially dangerous.

The TS will learn more and have greater success if he starts with a handful of basic components and uses them to build safe low-voltage circuits such as amplifiers, flip-flops, LED flashers, timers, oscillators.........etc...

 

These TVs are probably at least 30 years old, there is nothing useful in these big dusty old boxes and the TS is talking about collecting 8 of them! Remember, the TS has no electronics experience so all this talk of utilising the high-voltage stuff or building an oscilloscope is irrelevant and potentially dangerous.

The TS will learn more and have greater success if he starts with a handful of basic components and uses them to build safe low-voltage circuits such as amplifiers, flip-flops, LED flashers, timers, oscillators.........etc...

As usual but for the TS it is relevant or may look like a plan.

Some pictures in the attach...TS could contact me to arrange have some kilograms "ewaste" shipped to him.
I can get him old PCBs too by the kilogram- shipping cost in excess of the items.
Well unused parts cost me about $20 / kilogram, I could arrange to sell for $30 + shipping (which is about 12 Euro / kg). And thats without my own shipping costs too which are between $10 and $20 kilogram, and much less for old PCBs.

Actually certain parts can be cheaper new, but others, can be considerably cheaper as NOS.

I can also fish out certain parts, or presort larger lots (with price increase), or arrange direct shipping (lower shipping cost).

With some specifications, I can create component kits from NOS parts, and new parts too.

If you think about long hours or days dissecting these appliances, create a lot of dirt + inhale the plastic fumes + worry about the remains, investing some $ for parts makes more sense.

You can buy off ebay, DX etc., but there are cheaper sources too.

 

These TVs are probably at least 30 years old, there is nothing useful in these big dusty old boxes and the TS is talking about collecting 8 of them! Remember, the TS has no electronics experience so all this talk of utilising the high-voltage stuff or building an oscilloscope is irrelevant and potentially dangerous.

The TS will learn more and have greater success if he starts with a handful of basic components and uses them to build safe low-voltage circuits such as amplifiers, flip-flops, LED flashers, timers, oscillators.........etc...

I've dissected many TV sets particulary, cleared out the circuit boards, I was young and didnt understand the circuits properly, but I got exposed to a lot of components early in my life.
Then I did let them be for some years in favour of "computer programming".
Never got a punch from a CRT HV yoke but a lot from other, stupid and dangerous experiments.

One of my favourites was connecting transformers in reverse which of course would overheat quickly.

 

That's why most people do like the Elektor project and build an add on box that modulates a video signal to produce a facsimilie of the waveform on the existing raster-scan.

You can also make a UHF spectrum analyser out of an old TV - the vertical sawtooth is dimensioned to 30V and fed to the tuning varicap, a comparator compares the AGC voltage with a sample of the 30V sawtooth to determine at what point on the scan the beam is turned on or off.

Ah yes! I recall seeing such devices described in the 'Popular Electronics' periodical (Wayyy) back in the day...

Best regards
HP

 

My very first TV eventually developed EHT rectifier problems - the number had rubbed off so I got an EY87 replacement when it should've been a DY87, so the problems persisted until the error was pointed out,

IIRC, here in JEDEC land that'd be 1S2 vs 6S2 -- Indeed! Thermionic devices just plain work better with sufficiently heated cathodes!

Even with plenty of practice, it took me a while to remember that the CRT final anode was connected to the EHT rectifier cathode (and valve socket) - this resulted in me "manually" discharging the final anode capacitance a few times.

Ouch!

I'm embarrassed to confess that my lesson in the virtues of charge abatement came in the form of a dropped 21FJP22 --- with anticipatable, well neigh lamentable, results!

Best regards
HP

 

These TVs are probably at least 30 years old, there is nothing useful in these big dusty old boxes and the TS is talking about collecting 8 of them! Remember, the TS has no electronics experience so all this talk of utilising the high-voltage stuff or building an oscilloscope is irrelevant and potentially dangerous.

The TS will learn more and have greater success if he starts with a handful of basic components and uses them to build safe low-voltage circuits such as amplifiers, flip-flops, LED flashers, timers, oscillators.........etc...

While I sympathize with, and, indeed, share, some of your concerns, I, nonetheless, hold that sustained pursuit of avocation (or, indeed, any venture) requires an admixture of both passion and practicality -- granted while ICs, etc. represent a sensible, safe 'starting point' -- pedagogical, even safety, considerations should not, and, in my experience, do not, 'trump', the requisite ardor to be found solely along "The Road Not Taken"...

With respect all around and apologies to Robert Frost

Best regards
HP

 

While I sympathize with, and, indeed, share, some of your concerns, I, nonetheless, hold that sustained pursuit of avocation (or, indeed, any venture) requires an admixture of both passion and practicality -- granted while ICs, etc. represent a sensible, safe 'starting point' -- pedagogical, even safety, considerations should not, and, in my experience, do not, 'trump', the requisite ardor to be found solely along "The Road Not Taken"...

With respect all around and apologies to Robert Frost

Best regards
HP

I'm sure Mr. Frost will forgive you.

 

I am not advising against deconstructing hardware and salvaging of parts but old CRT TV sets are very poor candidates. Printer/scanners, for instance, can also be obtained free and contain a mixture of useful, modern and, otherwise expensive, stepper motors (generators), gears, drive belts, switches, slide rails and opto-sensors which all have value and provide greater opportunities for imaginative re-deployment.

 

I am not advising against deconstructing hardware and salvaging of parts but old CRT TV sets are very poor candidates. Printer/scanners, for instance, can also be obtained free and contain a mixture of useful, modern and, otherwise expensive, stepper motors (generators), gears, drive belts, switches, slide rails and opto-sensors which all have value and provide greater opportunities for imaginative re-deployment.

Depends what you're into.

For building circuits, the harvest from an old TV is far more usefull.

Although the ICs tend not to be much use for projects, except maybe the SMPSU & AF amp chips - that's more than can be said for the ICs in a scanner.

 

I am not advising against deconstructing hardware and salvaging of parts but old CRT TV sets are very poor candidates. Printer/scanners, for instance, can also be obtained free and contain a mixture of useful, modern and, otherwise expensive, stepper motors (generators), gears, drive belts, switches, slide rails and opto-sensors which all have value and provide greater opportunities for imaginative re-deployment.

My first projects were Tesla coils and (DIY) synchrotrons (back in the 'pre-web'-aka-'on-your-own' Era) -- lots of trial and even more error ---- Thus, being, as I am, an inveterate 'HV' enthusiast, I may be a tad biased (pun not necessarily not intended)

Best regards
HP

 

My first projects were Tesla coils and (DIY) synchrotrons (back in the 'pre-web'-aka-'on-your-own' Era) -- lots of trial and even more error ---- Thus, being, as I am, an inveterate 'HV' enthusiast, I may be a tad biased (pun not necessarily not intended)

Best regards
HP

I didnt like the big efforts needed for a Tesla coil- so, after researching 1000s of webpages, I came up with a design using off the shelf Inductor + winding 8 turns on it- job done. Smallest Tesla coil in the world!

It does work like a Tesla coil- you can hold LED in one hand, and just touch one terminal!
http://ledmatrix16lf1709.hitechworld.org/

Problem with TV parts is, they are highly specialized, and often not particulary good, just on the margin doing their job. ICs tend to be completely useless, the recent CRT TVs just have a few or just one.

transistors also often will be poor, function different than standard types in terms of hFE and current, often PNP which is a thinking barrier to beginners.