Help please with Tek 465 problem

[Yzordderex]

I recently bought a Tek 465. It was working fine, but now scope
traces aren't sweeping across. Just a pair of dots where channels are
supposed to be. I'm not too familiar with this type scope and was
wondering if it's possible that I accidently moved a control and lost
the sweep. I've pretty much tried everything in the way of fiddling
with controls. But maybe secret button somewhere I don't know of.

Ok, so assuming it's a problem inside scope, what am I looking at in
the way of circuits? Obviously there's a sweep oscillator generating
I would guess a sawtooth. Is there some kind of integrated circuit
with a Tek part number on it that's not going to be easy to get hold
of? Or am I likely to find run of the mill parts that I probably have
kicking around.


I guess what I'm asking for is for someone to take a peek at schematic
and give me thumbs up or down. I have another scope and my
troubleshooting skills are good, just don't have schematic in front of
me. If job is no-brainer I'll get hold of a schematic and go for it.
Otherwise have to ship it back to guy I bought from and pay him to fix
and ship back $$$.

Thanks guys.

Regards,
Bob

 

[Jim Yanik]

yzordderrex@verizon.net (Yzordderex) wrote in
news:a69e22f6.0312131830.7fa27e42@posting.google.com:

I recently bought a Tek 465. It was working fine, but now scope
traces aren't sweeping across. Just a pair of dots where channels are
supposed to be. I'm not too familiar with this type scope and was
wondering if it's possible that I accidently moved a control and lost
the sweep. I've pretty much tried everything in the way of fiddling
with controls. But maybe secret button somewhere I don't know of.

A sweep mode,AUTO trigger,AC coupling.Press beam find to see if it's a
blanking problem.Does horizontal position control affect the display,or
just move the dots?

Ok, so assuming it's a problem inside scope, what am I looking at in
the way of circuits? Obviously there's a sweep oscillator generating
I would guess a sawtooth. Is there some kind of integrated circuit
with a Tek part number on it that's not going to be easy to get hold
of? Or am I likely to find run of the mill parts that I probably have
kicking around.

The scope uses a TEK-made sweep logic IC. 155-0049-0X. (-02 was the last
known version of this IC ) They do fail,but not often.(not a likely
failure,IOW) Could even be an unblanking problem.Check the CRT neck pins
for a sweep ramp.(accessible on the bottom board,red and green wires)
Vertical is brown and blue.

I guess what I'm asking for is for someone to take a peek at schematic
and give me thumbs up or down. I have another scope and my
troubleshooting skills are good, just don't have schematic in front of
me. If job is no-brainer I'll get hold of a schematic and go for it.
Otherwise have to ship it back to guy I bought from and pay him to fix
and ship back $$$.

Thanks guys.

Regards,
Bob

Well,first thing is to check the power supplies with a meter to see if they
are the correct voltages,then check ripple with a scope.Vary the line V to
check regulation.The electrolytics are known to dry out,even leak all over
the interface board.(bottom board)

The service manual has an EXCELLENT circuit description section that tells
you exactly how everything works in detail.It's a must-have.

--
Jim Yanik,NRA member
jyanik-at-kua.net

 

[James Sweet]

Does vertical deflection work? I lost horizontal on mine once when a wire
fell off the deflection pin on the CRT.

"Yzordderex" <yzordderrex@verizon.net> wrote in message
news:a69e22f6.0312131830.7fa27e42@posting.google.com...

I recently bought a Tek 465. It was working fine, but now scope
traces aren't sweeping across. Just a pair of dots where channels are
supposed to be. I'm not too familiar with this type scope and was
wondering if it's possible that I accidently moved a control and lost
the sweep. I've pretty much tried everything in the way of fiddling
with controls. But maybe secret button somewhere I don't know of.

Ok, so assuming it's a problem inside scope, what am I looking at in
the way of circuits? Obviously there's a sweep oscillator generating
I would guess a sawtooth. Is there some kind of integrated circuit
with a Tek part number on it that's not going to be easy to get hold
of? Or am I likely to find run of the mill parts that I probably have
kicking around.


I guess what I'm asking for is for someone to take a peek at schematic
and give me thumbs up or down. I have another scope and my
troubleshooting skills are good, just don't have schematic in front of
me. If job is no-brainer I'll get hold of a schematic and go for it.
Otherwise have to ship it back to guy I bought from and pay him to fix
and ship back $$$.

Thanks guys.

Regards,
Bob

 

[bg]

Put both A and B trigger in normal position. Put mode in auto, put scope in
A sweep only. Trigger levels to "+" and midpoint
Three basic sections - horizontal amp, trigger generator, sweep generator.
If the hor. position knob moves the dots, it's a good bet that the
horizontal amp is good (or try the XY mode ). If you have Trigger pulses
from the gate outputs on the back of the scope, your triggers are working.
To check the sweep generator , you need to get inside and have a schematic.
Theres a load of other signals such as blanking, holdoff etc - the manual is
a must for these things.
Yzordderex wrote in message ...

I recently bought a Tek 465. It was working fine, but now scope
traces aren't sweeping across. Just a pair of dots where channels are
supposed to be. I'm not too familiar with this type scope and was
wondering if it's possible that I accidently moved a control and lost
the sweep. I've pretty much tried everything in the way of fiddling
with controls. But maybe secret button somewhere I don't know of.

Ok, so assuming it's a problem inside scope, what am I looking at in
the way of circuits? Obviously there's a sweep oscillator generating
I would guess a sawtooth. Is there some kind of integrated circuit
with a Tek part number on it that's not going to be easy to get hold
of? Or am I likely to find run of the mill parts that I probably have
kicking around.


I guess what I'm asking for is for someone to take a peek at schematic
and give me thumbs up or down. I have another scope and my
troubleshooting skills are good, just don't have schematic in front of
me. If job is no-brainer I'll get hold of a schematic and go for it.
Otherwise have to ship it back to guy I bought from and pay him to fix
and ship back $$$.

Thanks guys.

Regards,
Bob

 

[Jim Yanik]

"bg" <bg@nospam.com> wrote in
news:brin96$ic4$1@terabinaries.xmission.com:

Put both A and B trigger in normal position. Put mode in auto, put
scope in A sweep only. Trigger levels to "+" and midpoint
Three basic sections - horizontal amp, trigger generator, sweep
generator. If the hor. position knob moves the dots, it's a good bet
that the horizontal amp is good (or try the XY mode ). If you have
Trigger pulses from the gate outputs on the back of the scope, your
triggers are working.

Point;
I believe the gates are present when the -sweep gens- are producing a
ramp,not when a trigger is present.But in AUTO mode,you don't need any
trigger to get a sweep,it's free-running.

To check the sweep generator , you need to get

inside and have a schematic. Theres a load of other signals such as
blanking, holdoff etc - the manual is a must for these things.

--
Jim Yanik,NRA member
jyanik-at-kua.net

 

[Yzordderex]

Thanks guys.

Couldn't get scope going, but guy I bought it from is going to swap
out for another reworked unit no charge. He's good to deal with and
going out of his way to make me a happy customer.

Happy Holidays
Yzordderrex