Help with a B&K 1460 oscilloscope - I am trying to fix i

[gkaralus]

Help with an old scope

Hi again.
I am trying to fix an B&K 1460 oscilloscope.
It comes on, but I only can get it to display a dot, if I connect it to the signal generator I can get it to display 2 dots separated acordingly the voltage and scale
the dot(s) are always to the left of the screen, I can't get it to center.
so I disconected the plates and then the dot gets near the center.
The collector of Q23 averages to 50v when it should be 80v
and then the collector of Q22 averages 160 instead of 120v
Any help will be apreciated

 

[Siniša]

Re: Help with an old scope

Looks like Q22 and Q23 are in vertical deflection and you have problem with horizontal deflection. Q21/20 and previous circuitry would be place to look.

 

[gkaralus]

Help with an old scope

Hi, thanks for the help
The "variable horizontal gain" board is fine, q21 and 22 there have the right voltage , more or less.
Now in the other board: the base of q21 (next to q22) has 3.6v when the switch s103g connects pin 20 to pin 14
When I move the switch to the last position down to connect pin 20 to pin 8, the voltage drops to 1.6 and the voltages of q22 and q23 are good and I can move the dot horizontaly across the screen.
Now what I cant understand is the diagram sugest that the right voltage at pin 8 of s103g should be 3.5v and the base of q21 should be 1.1v, That can't be they are suposed to be connected together via the switch.
Am I using the wrong multimeter? ( a digital one ) Should I use an analog?