TeK 453 Scope Questions Please Help?


jonkzak <jonkzak@...>
 

All,

I've just received my used 453 and when I turned it on The only way
to get a trace is to hold the trace find button down and then the
trace is very small located on the right side of the screen. I did
open the covers and just looked around to see if anything looked
burned etc. I did notice this effect. When I toggle the on/off
switch to 'on' there is a lamp located on the bottom pc board that
will flash on then off and stays off. Turning the on/off switch
to 'off' will also flash this lamp. I don't know if this is normal
or not. Also all other pilots on the front of the scope function as
normal. The small trace does seem to look correct using the
calibrate signal as input. Any help would be greatly appreciated.
I'm sure that this has been covered but my search has not resulted in
any hits.

Best Regards,

Jon


ehsjr@...
 

jonkzak wrote:

All,
I've just received my used 453 and when I turned it on The only way to get a trace is to hold the trace find button down and then the trace is very small located on the right side of the screen. I did open the covers and just looked around to see if anything looked burned etc. I did notice this effect. When I toggle the on/off switch to 'on' there is a lamp located on the bottom pc board that will flash on then off and stays off. Turning the on/off switch to 'off' will also flash this lamp. I don't know if this is normal or not. Also all other pilots on the front of the scope function as normal. The small trace does seem to look correct using the calibrate signal as input. Any help would be greatly appreciated. I'm sure that this has been covered but my search has not resulted in any hits.
Best Regards,
Jon
Maybe this is a horizontal centering problem, or the scope is in
non-standard mode (delayed sweep, A intensified during B,
something other than standard). Double check that the controls
are all set where they should be. Someone may have removed
knobs and reinstalled them in the wrong orientation.

Ed


Howard Matthews
 

My first guess, Jon, would be a problem in the horizontal
amplifier. Check the horizontal deflection pins, they should both
read about 48 volts (+/- a few volts). I'll bet they don't. (Well,
according to your description, that is a DUH!) But if the
horizontal amp is working, the two voltages should add up to about
96 volts. If not, then there is a problem in this balanced
amplifier.

I had one scope with similar problems. The horizontal and vertical
output transistors for all these Tek scopes are in an odd holder,
with a rigid plastic strap across the top that both holds the
transisters in place, and provides the collector (as I recall)
connection to the transistor through it's case. During transit,
these straps can be jiggled out of place. Look for these four
transistors with the rigid strap across the top. Check the
transistors connected to the "horizontal amp" board - wiggle,
tighten as needed - simple fix.

If the transistors are all seated correctly, I would probe through
the horizontal amp checking voltages against the manual. But I'm a
relative newbie to fixing scopes, so there should be some other good
suggestions.... If you don't have the manual, checking the
horizontal amp is going to be a bit tough.

-Howard

--- In TekScopes@yahoogroups.com, "jonkzak" <jonkzak@y...> wrote:
All,

I've just received my used 453 and when I turned it on The only
way
to get a trace is to hold the trace find button down and then the
trace is very small located on the right side of the screen. I
did
open the covers and just looked around to see if anything looked
burned etc. I did notice this effect. When I toggle the on/off
switch to 'on' there is a lamp located on the bottom pc board that
will flash on then off and stays off. Turning the on/off switch
to 'off' will also flash this lamp. I don't know if this is
normal
or not. Also all other pilots on the front of the scope function
as
normal. The small trace does seem to look correct using the
calibrate signal as input. Any help would be greatly
appreciated.
I'm sure that this has been covered but my search has not resulted
in
any hits.

Best Regards,

Jon


Stan & Patricia Griffiths <w7ni@...>
 

One thing you can check, Jon, is that the pin connections to the CRT neck
are secure. I have seen these come off in transit. I also have to
emphasize that 90% of ALL scope prblems are in the power supplies. You will
need a manual if you don't have one. The first thing to do is check to make
sure the power supplies are working correctly. All bets are off unless the
power supplies are working correctly. The correct operation of the power
supplies is critical to every other circuit in the scope so you must start
there.

Ask again, when you have a manual and have confirmed correct power supply
operation.

Stan
w7ni@easystreet.com

----- Original Message -----
From: "jonkzak" <jonkzak@yahoo.com>
To: <TekScopes@yahoogroups.com>
Sent: Monday, November 17, 2003 9:33 AM
Subject: [TekScopes] TeK 453 Scope Questions Please Help?


All,

I've just received my used 453 and when I turned it on The only way
to get a trace is to hold the trace find button down and then the
trace is very small located on the right side of the screen. I did
open the covers and just looked around to see if anything looked
burned etc. I did notice this effect. When I toggle the on/off
switch to 'on' there is a lamp located on the bottom pc board that
will flash on then off and stays off. Turning the on/off switch
to 'off' will also flash this lamp. I don't know if this is normal
or not. Also all other pilots on the front of the scope function as
normal. The small trace does seem to look correct using the
calibrate signal as input. Any help would be greatly appreciated.
I'm sure that this has been covered but my search has not resulted in
any hits.

Best Regards,

Jon





Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/