Re: how to safely dismount the 475 vertical board


pe1fbo@...
 

--- In TekScopes@y..., "Emanuele Girlando" <emanuele_girlando@y...>
wrote:
Referring to my other post "tek 475 vertical position pots", I am
now
required to dismount those pots. To do it (the one for channel 2 in
particular), I have to remove the vertical amplifiers board.
What I am afraid of is that it seems I have to desolder two
resistors
having one lead on the borad and one on the VOLTS/DIV rotary
switches.
Can I do it safely? Anything to be aware of?
Furtheremore, how can I safely dismount the BW/TRIG VIEW command
shaft from the switch it is linked to? Is it sufficient to unscrew
the tiny screws?
Thank a lot
ciao
Hi Emanuele,

You can safely desolder the two resistors. They are connected to the
input FET. Just make sure that your solderingiron ground is on the
same potential as the scope, otherwise you could damage the input FET
(2N5911 discontinued by VISAY). The BW trig view screw (I think allen-
key 1/16") is best taken loos at the switch.

On most 475s there is also a strap from the main board to the
vertical board which can easy be overlooked. It is close to the HV
section. You have to unsolder it as well. The same with the Delay
line which is normaly soldered to the vertial amp board.

Good luck.

Fred de Vries

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