Re: 485 service manual is causing brain oscillations


satbeginner
 

Ok,

If the trimpot does not work, check the resistors around the trimpot and
the trimpot itself.


The way I understood the text in step 13 is:

If no improvement in the voltage can be reached by this procedure, set it
back to the voltage found earlier, and continue with step 14.

Again, I would check the components around the trimpot first.

Good luck,

Leo



On Sat, 24 Apr 2021, 06:26 Ondrej Pavelka, <info@vintageaudiorepairs.eu>
wrote:

Yeah yours is fixed, I still think I have a problem there because it says
to reset it back to noted voltage but in my case the trimpot setting has no
impact on the voltage value.

Your manual is later updated version without typo.

On Fri, 23 Apr 2021, 23:47 satbeginner, <castellcorunas@gmail.com> wrote:

Again sorry, no attachments...

I added my page to this album:

https://groups.io/g/TekScopes/album?id=262133

Leo

Op vr 23 apr. 2021 om 23:44 schreef satbeginner via groups.io
<castellcorunas=gmail.com@groups.io>:

This is what My manual says: (sorry for the poor picture..)
The last time I calibrated my 485 this worked...

Leo
[image: IMG_20210423_234002_01.jpg]

On Fri, 23 Apr 2021, 22:51 Ondrej Pavelka, <
info@vintageaudiorepairs.eu>
wrote:

Hello to the group,

Is anybody on here familiar closely with 485 calibration? In
particular
the Auto Focus section.

There is a time continuum breach making my brain go into feedback
loop
and
self destruct.

It's point 13) If I simplify it, it says put 3MHz in Channel 1,
display
nice 2 divisions high sinewave and adjust focus and astigmatism at
low
intensity for sharp trace. That works perfectly.
Next step is to raise intensity to 50V and check if focus bias does
anything, if it does you continue the procedure if it does not you
are
advised to skip forward to 13. This is where my brain melts. Because
13
is
definitely skip backwards and it says nothing about how to resolve
this
situation.

In my case focus bias does nothing with Z out voltage at all nor does
it
anything with actual focus.

Any ideas?

















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