Tektronix T-912 acting up: no trace

W

whipaway

Guest
I was using my t-912 for about an hour, then I walked away and came
back, there was no trace anymore. The crt filament lights up fine, and
I can see the trace briefly appear then I turn off the power switch,
so for some reason it is being blanked, I guess. The beam finder does
not help finding the beam.
Not having a schematic I don't know what voltages to check for at the
various test points.
If anyone has any suggestions, or a schematic, please let me know.
whipaway@bigfoot.com
 
whipaway@bigfoot.com (whipaway) wrote in
news:8ee08e67.0307100852.75045252@posting.google.com:

I was using my t-912 for about an hour, then I walked away and came
back, there was no trace anymore. The crt filament lights up fine, and
I can see the trace briefly appear then I turn off the power switch,
so for some reason it is being blanked, I guess. The beam finder does
not help finding the beam.
Not having a schematic I don't know what voltages to check for at the
various test points.
If anyone has any suggestions, or a schematic, please let me know.
whipaway@bigfoot.com
Click to expand...
Ebay or www.big-list for a service manual,or
http://www.logwell.com/tech/oscilloscopes/manuals.html

--
Jim Yanik,NRA member
remove null to contact me
 
Is anyone can scan and emal me the shematic for the power supply
board, I would appreciate it greatly.
whipaway@bigfoot.com
Jim Yanik <jyanik@nullkua.net> wrote in message news:<Xns93B4CB5885A57jyanikkuanet@204.117.192.21>...
whipaway@bigfoot.com (whipaway) wrote in
news:8ee08e67.0307100852.75045252@posting.google.com:

I was using my t-912 for about an hour, then I walked away and came
back, there was no trace anymore. The crt filament lights up fine, and
I can see the trace briefly appear then I turn off the power switch,
so for some reason it is being blanked, I guess. The beam finder does
not help finding the beam.
Not having a schematic I don't know what voltages to check for at the
various test points.
If anyone has any suggestions, or a schematic, please let me know.
whipaway@bigfoot.com


Ebay or www.big-list for a service manual,or
http://www.logwell.com/tech/oscilloscopes/manuals.html
Click to expand...
 
whipaway@bigfoot.com (whipaway) wrote in
news:8ee08e67.0307160837.6ff125e6@posting.google.com:

I checked the Power supply PCB and there is 13v on the 120V output, i
checked all of the components on the PCB everything is OK, maybe xfrmr
is bad?
Click to expand...
I don't have a schematic either,so I can't answer this. There may be a
small fuse on a small PCB on the xfmr.
Jim Yanik <jyanik@nullkua.net> wrote in message
news:<Xns93B4CB5885A57jyanikkuanet@204.117.192.21>...
whipaway@bigfoot.com (whipaway) wrote in
news:8ee08e67.0307100852.75045252@posting.google.com:

I was using my t-912 for about an hour, then I walked away and came
back, there was no trace anymore. The crt filament lights up fine,
and I can see the trace briefly appear then I turn off the power
switch, so for some reason it is being blanked, I guess. The beam
finder does not help finding the beam.
Not having a schematic I don't know what voltages to check for at
the various test points.
If anyone has any suggestions, or a schematic, please let me know.
whipaway@bigfoot.com


Ebay or www.big-list for a service manual,or
http://www.logwell.com/tech/oscilloscopes/manuals.html
Click to expand...


--
Jim Yanik,NRA member
remove null to contact me
 
C478 had become shorted. Replacing it with .033uF @ 400V cured the problem.

whipaway@bigfoot.com (whipaway) wrote in message news:<8ee08e67.0307100852.75045252@posting.google.com>...
I was using my t-912 for about an hour, then I walked away and came
back, there was no trace anymore. The crt filament lights up fine, and
I can see the trace briefly appear then I turn off the power switch,
so for some reason it is being blanked, I guess. The beam finder does
not help finding the beam.
Not having a schematic I don't know what voltages to check for at the
various test points.
If anyone has any suggestions, or a schematic, please let me know.
whipaway@bigfoot.com
Click to expand...
 
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