BWD 1722B large screen CRO

[duodiode62]

Hello.  I recently obtained a BWD 1722B oscilloscope and would like to obtain a service manual for it, or at least a decent circuit diagram.  Can anyone out there be of help?

Cheers, Stuart

[tautech]

Welcome to the forum.

Oh wow.....and it's like large display DSO's today are something new ! 

The best BWD resource is Kevin Chant and if he hasn't posted any documentation on these drop him a line with maybe a link back to this thread to see the size of that beast. 
https://www.kevinchant.com/bwd.html

[amspire]

It is probably sharing some of the circuitry with other models which have documentation.

Is it a tube + transistor circuit inside? It looks a bit like their 5MHz oscilloscope models.

Richard

[duodiode62]

Thanks Richard.  I'll have a look at other models.  Yes, it is a hybrid design, with 6CW4 nuvistors in the vertical amplifiers and 12AT7s in the time base, as well as lots of transistors.  The E.H.T. generator also has valves.  I may have come unstuck here, as the core of the E.H.T. generator transformer is broken; however, it does look like a Philips standard line output transformer as used in millions of 1960s B&W TV sets, so I may be able to find a replacement.  The vertical and horizontal deflection power amplifiers use heaps of 2N3055s driving what looks like a standard TV deflection yoke.  The CRT is a '50s style 70 degree 17" TV type, looks to be a 17CGP4.

Thanks Tautech.  I've looked at Kevin Chant's site, and its not there.  But I will have a look through to see if there are similar pre-amplifier and time base designs.

Cheers, Stuart

[james_s]

An analog scope using magnetic deflection has got to be very slow by scope standards. It might make a good vector monitor to play something like Asteroids on.

[amspire]

That scope turns out to be only 15kHz bandwidth - that is not a misprint. Trigger goes to 25kHz.

It is designed for viewing electro-medical outputs, classroom demonstrations and servo waveforms.

1722B is the mainframe and plugins include 17A (balanced input to 25mV/div), 17B/2 (unbalanced 30mV/div) and 17D (50uV/div).

So I doubt that looking at any other manuals would help - it is a very specialised model.