I've had my 475 for about 3 years and it does the same thing. On initial turn on it's bright and then dims a bit after 5-10 minutes. Both traces also take a bit of time to settle in vertically, as well. I think I've been told by the group here before that it's normal. It works quite well and I have no intention of "fixing" it until something actually breaks. I've done a couple of repairs and replaced some failure-prone tantalums before they failed but I'm not recapping it until it actually tells me it needs recapping.
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Redguuz <firstname.lastname@example.org>
Sent: Thursday, February 7, 2019 6:46 AM
Subject: [TekScopes] TEK: 475 Long stabilization times normal: or Failure dooming.
I own a TEK 475 scope (Made in Holland).
I bought this (third hand) from a local Market site.
Ever since I own this scope, it behaves as follows:
It takes quite some time (~10 minutes) before it is fully stabilized (focus, vertical positioning ).
My work room is normally not heated (it is now winter), so might this simply be due to the need of heating up of components?
Or is this a sign of catastophe coming (e.g. in the Power supplies due to e.g bad tantalum capacitors).
Are there known failure prone compoenets, which in your opinion, could be preemtively replaced, before creating a chain reaction, due to failure.
Appreciate your experience with this scope.