Excellent answer. ?That's exactly what I found in one of my 475s that was DOA when I got it.
On 26 Jun 2012, at 21:15 , Tom Jobe wrote:
?
Hi John,
Taking your guess just a bit further, I would guess that one
of those pesky tantalum capacitors is the problem on the mainboard.
Check the resistance to ground of each low voltage supply at
its test point to get started.
The tantalums are multi colored "dipped"?capacitors, and
the ones that often fail are in the 10uF to 47uF range.
tom jobe...
?
?
?
----- Original Message -----
Sent: Tuesday, June 26, 2012 5:50
PM
Subject: [TekScopes] Tektronix 475A
failed during initial use
?
My 475A Oscilloscope powered up fine and as I was adjusting the
trace, the scope
just died, like a classic scope putting itself to sleep. ?I can
still hear the power trans-
former and the fuses on the rear panel are good (they are not blown).
?
This is a scope which I have not had much time to use but because of its
age I am
very surprised it did this.?
I'm going over some documentation that Dino Pappas kindly sent to me but
I am?
wondering if anyone has been through this and if so, what might be the
issue? ?I am
guessing the problem is with the A9 main board ?
Thanks,
John
