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Problem with Tektronix scope 7313
(Holger Menges) wrote in
om:
Hello,
thanks for your help, I've got a Service Manual for the Scope. But now
I've got 2 new Problems:
- the line fuse was blown after a short time when I switched on the
scope. Which Units should I disconnect for the LV - Test?
- How should I test the HV - unit? It's installed behind a shield and
two other PCBs are mounted on the shield.
I also think the Problem is in the HV - section, because the crackling
came from this direction.
Greetings,
Holger
IIRC,There's a fuse on the cap rectifier board(top board on the lower rear
module,above the pwr xfmr) that supplies -15 unreg to the HV. If the HV has
a problem,that should open.Ribbon cables to the Z-axis PCB can be pulled to
isolate the HV/Z-Axis from the LV supplies.Check the manual for the right
ones to pull.Then,IIRC,the cal procedure identifes the place to measure the
LV supplies.
The LV regulator board (top assy at rear)has to be connected to the
interface PCB(where the plug-ins connect) by 2 ribbon cables to maintain
sense feedback and decoupling.The LV reg can have cracked solder joints on
the studs for the TO-3 collector screws,causing LV problems.also,the 'IC'
on the LV reg PCB should have the socket removed and the 'IC'(5-xstr array)
soldered direct to the PCB.
Note,the circuit description is a great source of info for knowing how the
scope circuits work. Read it!!
--
Jim Yanik
jyanik-at-kua.net
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