using oscilloscope crt+power supply

Thread Starter

uv147

Joined Dec 24, 2015
18
hi
i found two crt and power supplys of ascilloscopes on ebay:

http://www.ebay.com/itm/Tektronix-300MHz-Oscilloscope-CRT-2440-154-0850-01-Power-Supply-670-9748-04-/271955460673?hash=item3f51cf0241:g:fZcAAOSw5dNWlOxV

http://www.ebay.com/itm/Tektronix-150MHz-Oscilloscope-CRT-2445-With-Power-Supply-/272104974886?hash=item3f5ab86a26:g:TpEAAOSwKtlWl8ZW

will i be able to make it work and just display a dot on the screen without connecting the crt and the power supply to an actual oscilloscope?
thank you very much
 

Hypatia's Protege

Joined Mar 1, 2015
3,208
Display of even a 'dot' will require correct biasing (i.e. cathode, focus, pre-acceleration, etc...) -AND- charging of the deflection plates such that the beam impinges upon the 'screen area' (It appears that the first PSU (linked above) provides filament power and final/post accelerator potential) --- What are you trying to do?

Best regards
HP:)
 
Last edited:

Thread Starter

uv147

Joined Dec 24, 2015
18
i am trying to deflect the beam using my own helmholtz coils
Display of even a 'dot' will require correct biasing (i.e. cathode, focus, pre-acceleration, etc...) -AND- charging of the deflection plates such that the beam impinges upon the 'screen area' (It appears that the above linked PSU provides filament power and final/post accelerator potential) --- What are you trying to do?

Best regards
HP:)
i am trying to deflect the beam using my own helmholtz coils
 

Dodgydave

Joined Jun 22, 2012
8,797
The psu wont have any line scan circuits or vertical amplifier, it should just put the beam in the centre position with focus and brightness adjustment,

As for deflection, the tube uses deflection plates inside to move the beam up down, left right, not coils.

i would contact the seller and ask them for confirmation.
 

Thread Starter

uv147

Joined Dec 24, 2015
18
The psu wont have any line scan circuits or vertical amplifier, it should just put the beam in the centre position with focus adjustment, i would contact the sell and ask them for confirmation.
well i tried, they said they think it's possible but never tried it
 

Hypatia's Protege

Joined Mar 1, 2015
3,208
The psu wont have any line scan circuits or vertical amplifier, it should just put the beam in the centre position with focus ans brightness adjustment, i would contact the seller and ask them for confirmation.
It is very unlikely that the beam will be directed 'dead center' (or even on-screen) with the deflection plates merely floating or bonded/tied --- In my experience significant 'inherent' offset is always present...

i am trying to deflect the beam using my own helmholtz coils
Of course magnetic deflection of any CRT is possible - so long as you can manage location of the coils despite 'bulb' geometry, shielding, any 'neck pins', etc...:)

Best regards
HP
 
Last edited:

Thread Starter

uv147

Joined Dec 24, 2015
18
It is very unlikely that the beam will be directed 'dead center' (or even on-screen) with the deflection plates merely floating or bonded/tied --- In my experience significant 'inherent' offset is always present...


Of course magnetic deflection of any CRT is possible - so long as you can manage location of the coils despite 'bulb' geometry, shielding, any 'neck pins', etc...:)

Best regards
HP
so can i make the crt shoot a beam without the scope iself? because i see there is a wire in there not connected to the power suply in the picures
thank you
 

Thread Starter

uv147

Joined Dec 24, 2015
18
You seem to be under some misapprehension -- You are, in point of fact, contemplating construction of an oscilloscope!:confused:

Best regards
HP
yes kind of...

Do you want to make an Oscilloscope or just want to make the beam move left, right,up,down???
i only need the beam to move right up left and down, i am controling the beam by changing the current in the coils

Fair enough! -- Although I'm here to tell you that magnetic deflection of those tubes is as using a Lamborghini to deliver beer!:eek: --- You'll find it less expensive and much easier to use a TV CRT for your purposes!:cool:

Best regards
HP:)
i tried it, but it turns out to be almost impossible to disconnect the deflection plates, and using a color crt is too

Hello,

Here is the schematic of the 2445 HV powersupply and the CRT:

View attachment 99648

Bertus
thank you bertus, but the question is will the power suply and the crt will be enough for my needs or will i need to buy a full oscilloscope in order to make the crt just shoot a beam?
 

bertus

Joined Apr 5, 2008
20,317
Hello,

A CRT as shown uses voltage on the deflection plates to move the beam.

In the posted schematic, you will see some controls like focus, astig and trace rotaion.
Those are NOT on the supply.

Bertus
 
i tried it, but it turns out to be almost impossible to disconnect the deflection plates, and using a color crt is too
TV CRTs are magnetically deflected (hence no deflection plates) --- If you mean that the deflection yoke is chemically bonded to the neck/bulb, please be advised that it may readily be removed via application of ketone solvents (e.g. acetone) --- Also, although a colour tube will suffice, a monochrome CRT would be better applied to your demonstration... :)

Best regards
HP
 

Thread Starter

uv147

Joined Dec 24, 2015
18
Hello,

A CRT as shown uses voltage on the deflection plates to move the beam.

In the posted schematic, you will see some controls like focus, astig and trace rotaion.
Those are NOT on the supply.

Bertus
as i said above, the deflection plates are not needed as part of my demonstration, as i plan to move the beam using helmholtz coils
TV CRTs are magnetically deflected (hence no deflection plates) --- If you mean that the deflection yoke is chemically bonded to the neck/bulb, please be advised that it may readily be removed via application of ketone solvents (e.g. acetone) --- Also, although a colour tube will suffice, a monochrome CRT would be better applied to your demonstration... :)

Best regards
HP
 
as i said above, the deflection plates are not needed as part of my demonstration, as i plan to move the beam using helmholtz coils
That's my point -- Just remove the yoke (using solvent) - then replace it with your coil{s}:)

Again, television CRTs contain no deflection plates! --- So... no worries about 'interference' from same:cool::cool::cool:

Best regards
HP
 
Top