BWD 539B CRO

[Loco1960]

I have one of these old beauties but it has a problem, seems no horizontal timebase. The tube appears fine and has a single dot, focussable and movable in X and Y directions. Anyone experienced at fixing these?

[james_s]

Are you sure you are using it correctly? I've seen people have this symptom and it turns out they have the scope set in XY mode.

[tautech]

I have one of these old beauties but it has a problem, seems no horizontal timebase. The tube appears fine and has a single dot, focussable and movable in X and Y directions. Anyone experienced at fixing these?

Welcome to the forum.

Service manual if you don't already have one and for those playing along at home:
https://www.kevinchant.com/uploads/7/1/0/8/7108231/539b.pdf

[vk6zgo]

Have you checked that ir works on X-Y?

A common thing with some BWDs is the loss of internal triggering, which is because  they source their trigger from the output to the horizontal plates, via a high value resistive voltage divider.
The larger of the two resistors in the dividers goes high, reducing the trigger signal below the threshold.

Do you get a "free running" display in "auto"?.
If so, & you can control the sweep rate with the time/div control, try usiing an ecternal trigger signal.
If it now triggers, the fault is as referred to above.

[Loco1960]

 I misread the button positions in/out and indeed had it on X-Y