tektronix 2445 problem

[Ed]

I recently purchased a used Tektronix 2445. It worked fine for a week;
one day after using it for several hours suddenly it shut off and
turned on by its self. From that moment nothing was displayed in the
screen. I opened the unit and I found a burned fuse (125V 750mA) I
replaced with a new one and it burned instantly. I don't know what to
do and I don't have a service manual. If anyone has any suggestions of
what I should do please let me know,
Regards, Ed
pengued@comcast.net

 

[James T. White]

"Ed" <pengued@comcast.net> wrote in message
news:1164399116.842363.138550@f16g2000cwb.googlegroups.com

I recently purchased a used Tektronix 2445. It worked fine for a week;
one day after using it for several hours suddenly it shut off and
turned on by its self. From that moment nothing was displayed in the
screen. I opened the unit and I found a burned fuse (125V 750mA) I
replaced with a new one and it burned instantly. I don't know what to
do and I don't have a service manual. If anyone has any suggestions of
what I should do please let me know,
Regards, Ed
pengued@comcast.net

Go join Yahoo Groups - TekScopes. If you don't find what you need in
the archives, then ask there.

--
James T. White

 

[Jim Yanik]

"Ed" <pengued@comcast.net> wrote in
news:1164399116.842363.138550@f16g2000cwb.googlegroups.com:

I recently purchased a used Tektronix 2445. It worked fine for a week;
one day after using it for several hours suddenly it shut off and
turned on by its self. From that moment nothing was displayed in the
screen. I opened the unit and I found a burned fuse (125V 750mA) I
replaced with a new one and it burned instantly. I don't know what to
do and I don't have a service manual. If anyone has any suggestions of
what I should do please let me know,
Regards, Ed
pengued@comcast.net

ftp://bama.sbc.edu/downloads/tek/2465service/

for the service manual;2445 and 2465 are the same animal except for
bandwidth.(determined by the mother board PCB itself!)

Then your 2445 power supply needs troubleshooting and repair.
Probably a shorted diode and several electrolytic filter caps with high
ESR. Use switcher-grade low ESR caps,not your average RadioShack caps.

Read the circuit descrption to get an understanding of how the PS works.
DON'T go in blind. It's not like most switchers.

--
Jim Yanik
jyanik
at
kua.net