DIYbanter - View Single Post

wrote in
ps.com:

Hi,

got a Tek 2215a to repair. At start, caps on +5V was dead, making a
direct link between +5 and ground.

now I can see lines or signals on crt but wit maximum intensity, which
is not good.

Z-Axis logic is ok, if I turn either A or B intensity channel I can see
signal amplitude changing.
So problem comes from DC restorer, but even with service manual, I
can't see what's going wrong.

At the DC restorer's output (control grid) I only have the DC
component (which is -2 kv ??!!) and AC component from Z-Axis logic is
not here anymore. So I thought somes diodes where out but I checked
caps resistors and diodes all components seems to be ok. Also I checked
connection between DC restorer and CRT wires are's ok too. What can be
the problem ???

thanks and sorry for english level

Laurent

DC restorer diodes can break down under HV,and a normal DMM test will not
show that.If you do not have a curve tracer to test them to their rated
voltage,then swapping them out is the best method.

does adjusting the CRT bias pot (on main board)have any effect on beam
intensity?

--
Jim Yanik
jyanik
at
kua.net