Hello everyone, My oscilloscope has gone wrong. Was going fine then it
suddenly went out of focus for no reason. The focus knob hardly has an
effect, its majorly out of focus


any ideas ?

many thanks!

The model is:

Iwatsu SS 7636 350 MHz 4 channel


"Jamie" wrote in message
...
Barry Hobbs wrote:

Hello everyone, My oscilloscope has gone wrong. Was going fine then it
suddenly went out of focus for no reason. The focus knob hardly has an
effect, its majorly out of focus


any ideas ?

many thanks!


yeah, the focus or high voltage supply is crapped out.

leaky caps in the HV supply can cause this problem in a
large variety if scopes. of course this depends on the type
scope you have.

Barry Hobbs wrote:

Hello everyone, My oscilloscope has gone wrong. Was going fine then it
suddenly went out of focus for no reason. The focus knob hardly has an
effect, its majorly out of focus


any ideas ?

many thanks!


yeah, the focus or high voltage supply is crapped out.

leaky caps in the HV supply can cause this problem in a
large variety if scopes. of course this depends on the type
scope you have.

"Barry Hobbs" wrote in
:

Hello everyone, My oscilloscope has gone wrong. Was going fine then it
suddenly went out of focus for no reason. The focus knob hardly has an
effect, its majorly out of focus


any ideas ?

many thanks!



It certainly would help if you mentioned what make and model scope you
have.

If it were a 2213/2215,I'd say to look at the focus string of resistors,one
or more is out of spec.

--
Jim Yanik
jyanik
at
kua.net

"Jamie" skrev i meddelandet
...
Barry Hobbs wrote:

Hello everyone, My oscilloscope has gone wrong. Was going fine then it
suddenly went out of focus for no reason. The focus knob hardly has an
effect, its majorly out of focus


any ideas ?

many thanks!


yeah, the focus or high voltage supply is crapped out.

leaky caps in the HV supply can cause this problem in a
large variety if scopes. of course this depends on the type
scope you have.

Depends on what kind off focus supply you got, some days ago I was into a
Philips scope and the reason for poor focus was that the lower resistor in
the divider had gone up in value. As Jamie said leaky caps in the HV supply
can give you same trouble but if it suddenly goes bad check for bad solder
joints. Follow the shaft from the front panel to the rear of your scope and
check it out If you got proper instrumentation and knowledge you will
probably solve this.

Bjorn

The model is:

Iwatsu SS 7636 350 MHz 4 channel
thanks

"Jim Yanik" . wrote in message
.. .
"Barry Hobbs" wrote in
:

Hello everyone, My oscilloscope has gone wrong. Was going fine then it
suddenly went out of focus for no reason. The focus knob hardly has an
effect, its majorly out of focus


any ideas ?

many thanks!



It certainly would help if you mentioned what make and model scope you
have.

If it were a 2213/2215,I'd say to look at the focus string of
resistors,one
or more is out of spec.

--
Jim Yanik
jyanik
at
kua.net