(Using Lab-Volt System) Have the books, how do I get a trace on my 465 Tektronix oscilloscope

[Chris L]

Hello,

I already own the books "How to Use Oscilloscopes and Other Test
Equipment" by R. Penfold, "The XYZ's of Oscilloscopes" by Tektronix,
and "101 Ways to use your ... Oscilloscope" by R. Middleton.

How do I get something to show up on my scope?

I haven't used one in 10 years.

I set the channel 1 button, turned power on, hooked up correct lead to
a circuit board (Lav-Volt simulation of circuit where computer sim
told me to hook it up) from scope, hooked up a function generator
where the simulation told me to hook it up (sine wave, range 10X and
freq knob set to about 1) to circuit, tried focusing, tried
intensity, tried varying volt/div, and delay, but nothing would show
up.

How do I get something?


Thank you,
Christopher Lusardi

 

[Michael Black]

Hello,

I already own the books "How to Use Oscilloscopes and Other Test
Equipment" by R. Penfold, "The XYZ's of Oscilloscopes" by Tektronix,
and "101 Ways to use your ... Oscilloscope" by R. Middleton.

How do I get something to show up on my scope?

I haven't used one in 10 years.

I set the channel 1 button, turned power on, hooked up correct lead to
a circuit board (Lav-Volt simulation of circuit where computer sim
told me to hook it up) from scope, hooked up a function generator
where the simulation told me to hook it up (sine wave, range 10X and
freq knob set to about 1) to circuit, tried focusing, tried
intensity, tried varying volt/div, and delay, but nothing would show
up.

How do I get something?

You're probably starting with too much complication.

With the sensitivity up, any scope will show 60Hz sort of sinewave
(50Hz if that's what you've got coming out of your AC sockets) when
you touch the probe.

What you didn't say is what kind of oscilliscope. IN the old
days, the average scope was pretty rudimentary, and it required
no skill to get some sort of display. But when they got
fancier, the triggered sweep often confuses people, because
they forget to set one of the often numerous switches, and
that causes a lack of display.

Focusing won't do anything. Given a trace, it will merely allow
you to get a narrow trace. But it won't cause the trace to
disappear.

Intensity can be a factor, because if it's set too low, you
won't get a display, and if the sweep is really fast, you may
need to turn up intensity to see the trace.

Positioning is a really important factor. There should be
knobs for moving the trace vertically and horizontally, I'm
not sure the exact labelling or even if there is standard
labelling. If the trace is off-screen, you may never realize
there is a trace. Fancier scopes will have a momentary switch
which compresses the display, so no matter how far off-screen
the trace is, you will see it and be able to get it centered.
Otherwise, setting the adjustments to more or less center
should get you soemthing which can then be perfected.

But, if there's no trace, none of that will help.

Delay is usually about adding some delay between a trigger and
the display. I can't see it being a factor here.

Usually the lack of trace is because one of the switches
for setting the sweep triggering is in the wrong position. If
it's in a single-shot mode, the trace will go from left to right
once, each time it receives a trigger voltage of suitable level.
If the level isn't right, you may not be triggering the sweep
and hence no trace.

Something like "auto" is usually a good mode to start with.

The fancier sweep modes, the more work you have to do with
all the controls, so if the sweep trigger switch is set
to the "wrong" position, you may have to fiddle with the
trigger level controls to get the thing to trigger.

Of course, there's always the possibility that the scope
isn't working. If it's new to you, that's always a possibility.
Even if you've had it around for ten years, there is always
the possibility that something has gone wrong in that
time.

Michael

 

[JeffM]

How do I get something to show up on my scope?
I haven't used one in 10 years.
[...]tried focusing, tried intensity, tried varying volt/div, and delay,
but nothing would show up.
Christopher Lusardi

Has the instrument also been idle for 10 years?
If so, the lytics could have dried out / de-formed
and the scope just isn't working.
Slapping the juice to an electronic device
that has been in storage for an extended period is a gamble.

I would first try minimum sensitivity (10V/div??),
1ms/div, auto-trigger, and work the vertical position knob.
If you can turn the sweep off, you should get a dot.
Some scopes have a Beam Finder button.

 

[Chris L]

You're probably starting with too much complication.

With the sensitivity up, any scope will show 60Hz sort of sinewave
(50Hz if that's what you've got coming out of your AC sockets) when
you touch the probe.

What you didn't say is what kind of oscilliscope. IN the old
days, the average scope was pretty rudimentary, and it required
no skill to get some sort of display. But when they got
fancier, the triggered sweep often confuses people, because
they forget to set one of the often numerous switches, and
that causes a lack of display.

Focusing won't do anything. Given a trace, it will merely allow
you to get a narrow trace. But it won't cause the trace to
disappear.

Intensity can be a factor, because if it's set too low, you
won't get a display, and if the sweep is really fast, you may
need to turn up intensity to see the trace.

Positioning is a really important factor. There should be
knobs for moving the trace vertically and horizontally, I'm
not sure the exact labelling or even if there is standard
labelling. If the trace is off-screen, you may never realize
there is a trace. Fancier scopes will have a momentary switch
which compresses the display, so no matter how far off-screen
the trace is, you will see it and be able to get it centered.
Otherwise, setting the adjustments to more or less center
should get you soemthing which can then be perfected.

But, if there's no trace, none of that will help.

Delay is usually about adding some delay between a trigger and
the display. I can't see it being a factor here.

Usually the lack of trace is because one of the switches
for setting the sweep triggering is in the wrong position. If
it's in a single-shot mode, the trace will go from left to right
once, each time it receives a trigger voltage of suitable level.
If the level isn't right, you may not be triggering the sweep
and hence no trace.

Something like "auto" is usually a good mode to start with.

The fancier sweep modes, the more work you have to do with
all the controls, so if the sweep trigger switch is set
to the "wrong" position, you may have to fiddle with the
trigger level controls to get the thing to trigger.

Of course, there's always the possibility that the scope
isn't working. If it's new to you, that's always a possibility.
Even if you've had it around for ten years, there is always
the possibility that something has gone wrong in that
time.

Michael- Hide quoted text -

- Show quoted text -

Here are the details of my scope. Again, how do I get something to
come up on my scope. Do I have to have the leads connected to
something,

Here are buttons with the word trigger in them:

B Triggering
-----------------
(1) B(DLY'D) Trigger [has a 2 position toggle, and a fine knob on it]

Slope
Level
- 0 +


(2) Coupling [4 positions]
AC [top position]
LF REJ
HF REJ
DC [bottom]

(3) Source [5 positions]
Starts after delay [top]
Norm
Ch 1
Ch 2
Ext

(4) [Output connection]
1M Ohms 20 pF
[This seems to be related to the Source button]

A Triggering
----------------
(5) B Trigger
Slope
Level
- 0 +

(6) Coupling [4 positions]
AC [top position]
LF REJ
HF REJ
DC [bottom]

(7) Source [5 positions]
Starts after delay [top]
Norm
Ch 1
Ch 2
Ext

(8) [Output connection]
1M Ohms 20 pF
[This seems to be related to the Source button]

(9) Trigger Mode [has 3 buttons]
auto button
norm button
Singl Swp button (push to reset)

(10) A Trig Holdoff [continuous turn]

B ENDS A NORM Increase Serial


====================
There are also these buttons:

(A) Scale Illum
(B) A & B Sweep
-----------------
(B1) Delay Time Position has 2 knobs in 1, outter 0 to 9 and
inner 0 to 9 with inner causing outter to increment
(B2) A and B Time/Div and Delay Time [has 3 areas labelled s,
ms, and us]
s has 4 positions: X -Y, .5, .2, .1
ms has 9 positions: 50, 20, 10, 5, 2, 1, .5, .2, .1
us has 12 positions: 50, 20, 10, 5, 2, 1, .5, .2, .1, .05, .
02, .01
[This has 2 knobs labelled with 1st labelled DLYD SWP (Pull) and Lock
Knobs For A, and smaller inner one labelled Var]
(C) Hertz Display [4 buttons]
(C1) A Lock Knobs
(C2)Mix
(C3)A Inten
(C4) B DLYD
(D) Invert
(E) Beam Finder
(F)Each channel has a vertical position knob
(G)Horizontal position
(H)100 or 20MHz Bw (Full) [3 positions]

[Next are 5 located together:]
(I) Ch 1
(J)Alt
(K)Add
(L)Chop
(M)Ch 2

(N) X10 Mag (in)
(O) [There is something labelled calibrator which doesn't seem to
move, it has a "C" shaped bar connecting 2 things?]
(P) there are a few tiny lights:
3labelled UNCAL [one in A & B Sweep area]
X10 Mag
Ready in A & B Sweep area
Trig
(Q) How do I use the ground small hole
(R) Each of the 2 channels has output leads
(S)Each of the Volts/Div has a 3 position switch labelled AC, GND, and
DC.
(T) On the back of the scope, ae 4 outputs which the leads can connect
to. They are labelled:
1.A + Gate 500 Ohms 5.5 V
2.B + Gate 500 Ohms 5.5 V
3.Probe Power
4.Ch 2 Vert Signal Out 500 20mV/Div
There are also 2 holds with 4 holes inside each

Thank you,
Christopher Lusardi

 

[Chris L]

How do I get something to show up on my scope?
I haven't used one in 10 years.
[...]tried focusing, tried intensity, tried varying volt/div, and delay,
but nothing would show up.
Christopher Lusardi

Has the instrument also been idle for 10 years?
If so, the lytics could have dried out / de-formed
and the scope just isn't working.
Slapping the juice to an electronic device
that has been in storage for an extended period is a gamble.

I would first try minimum sensitivity (10V/div??),
1ms/div, auto-trigger, and work the vertical position knob.
If you can turn the sweep off, you should get a dot.
Some scopes have a Beam Finder button.

Here is a picture of the oscilloscope which shows it was working about
a month ago.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180146937400&sspagename=ADME:X:RTQ:US:11

The manual says the scope should be on for 20 minutes before using it.

Chris Lusardi

 

[gearhead]

Hello,

I already own the books "How to Use Oscilloscopes and Other Test
Equipment" by R. Penfold, "The XYZ's of Oscilloscopes" by Tektronix,
and "101 Ways to use your ... Oscilloscope" by R. Middleton.

How do I get something to show up on my scope?

I haven't used one in 10 years.

I set the channel 1 button, turned power on, hooked up correct lead to
a circuit board (Lav-Volt simulation of circuit where computer sim
told me to hook it up) from scope, hooked up a function generator
where the simulation told me to hook it up (sine wave, range 10X and
freq knob set to about 1) to circuit, tried focusing, tried
intensity, tried varying volt/div, and delay, but nothing would show
up.

How do I get something?

Thank you,
Christopher Lusardi

go here
http://bama.edebris.com/manuals/tek/475/
and download
475.pdf(13MB)
go to section 2 of the manual,
it tells how to get started.

 

[gearhead]

Hello,

I already own the books "How to Use Oscilloscopes and Other Test
Equipment" by R. Penfold, "The XYZ's of Oscilloscopes" by Tektronix,
and "101 Ways to use your ... Oscilloscope" by R. Middleton.

How do I get something to show up on my scope?

I haven't used one in 10 years.

I set the channel 1 button, turned power on, hooked up correct lead to
a circuit board (Lav-Volt simulation of circuit where computer sim
told me to hook it up) from scope, hooked up a function generator
where the simulation told me to hook it up (sine wave, range 10X and
freq knob set to about 1) to circuit, tried focusing, tried
intensity, tried varying volt/div, and delay, but nothing would show
up.

How do I get something?

Thank you,
Christopher Lusardi

sorry, I gave you the wrong link in that other post

http://bama.edebris.com/manuals/tek/465/
download the pdf and look at the operating instructions,
it should have the info you need for familiarizing yourself with
the scope

 

[ehsjr]

How do I get something to show up on my scope?
I haven't used one in 10 years.
[...]tried focusing, tried intensity, tried varying volt/div, and delay,
but nothing would show up.
Christopher Lusardi

Has the instrument also been idle for 10 years?
If so, the lytics could have dried out / de-formed
and the scope just isn't working.
Slapping the juice to an electronic device
that has been in storage for an extended period is a gamble.

I would first try minimum sensitivity (10V/div??),
1ms/div, auto-trigger, and work the vertical position knob.
If you can turn the sweep off, you should get a dot.
Some scopes have a Beam Finder button.

Here is a picture of the oscilloscope which shows it was working about
a month ago.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180146937400&sspagename=ADME:X:RTQ:US:11

The manual says the scope should be on for 20 minutes before using it.

Chris Lusardi

Preliminary check: turn it on and wait 1 minute,
turn the intensity all the way up (clockwise), push
the CH 1 button then press the beam finder button.
If you get nothing on the screen, turn the vertical
position knob for ch1 (upper left) to see if that brings
the trace on the screen. If you can't get a trace
that way, something is defective. The trace will be
shorter when you use the beam finder - that's normal.

Assuming you do get a trace while holding the beam finder
button in, use the vertical position knob to center it
vertically on the screen. Don't move that position knob
after that, for the remaining tests.

Repeat the above for CH2, by pushing the CH2 button in
and doing the same things - use the CH2 vertcal position
knob.

Next:
Set the scope for auto trigger by pushing the button in.
Move the AC GND DC switches to GND. You do not need scope
probes for this, so you are purposely grounding the input.
Set the remaining switches/knobs to match the ebay picture.
Make sure A lock knobs is in Auto is in trig view is in
(but not held in with your finger).

That's the basics. If you can't get it to display a trace
doing those things, it is likely defective. However, if
you don't get a trace, it would be a good idea to get someone
who is experienced with 'scopes to verify that the problem
is really in the scope and not with something you are doing.

Once you do get a trace, you can set it up to look at waveforms
using your probes & function generator. You set the input
switch (under the volts/div knob) to AC or DC, connect the
probe to the point you want to look at *and* connect the probe
ground clip to circuit ground. Then you need to turn the
volts/div to an appropriate setting, and the time/div knob
to a setting that shows a display of enough time to examine
the waveform. Properly triggering the scope will require
setting the source and coupling switches and fiddling with the
trigger level control.

The 475 is a fine scope, and you got it for a good price.
Good luck with it!

Ed

 

[Rose]

How do I get something to show up on my scope?
I haven't used one in 10 years.
[...]tried focusing, tried intensity, tried varying volt/div, and delay,
but nothing would show up.
Christopher Lusardi

Has the instrument also been idle for 10 years?
If so, the lytics could have dried out / de-formed
and the scope just isn't working.
Slapping the juice to an electronic device
that has been in storage for an extended period is a gamble.

I would first try minimum sensitivity (10V/div??),
1ms/div, auto-trigger, and work the vertical position knob.
If you can turn the sweep off, you should get a dot.
Some scopes have a Beam Finder button.

Here is a picture of the oscilloscope which shows it was working about
a month ago.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180146937400&sspag...

The manual says the scope should be on for 20 minutes before using it.

Chris Lusardi

Thats a nice scope.

 

[Chris L]

I tried what earlier posts said for about 20 minutes, and I have not
been able to get anything on the display. Question: The calibration
"C" bar is suppose to give a square wave, so if I pinch one probe on
it where do I put the ground probe? I tried putting the black probe
into a tiny hole.

Anyway, two UNCAL came one. The manual says the UNCAL lights indicate:

1)Light indicates that the VAR control is not in the calibrated
position. [They are talking about the fine knob on the Volts/div.]

2) Light that indicates when the VAR Time/Div control is out of the
calibrated detent and the horizontal sweep rate is uncalibrated. [They
are talking about the fine knob on the A and B Time/Div and Delay Time
knob.]

I couldn't get the lights to go out.

What do I try?

Should I try hooking the 2 function generator probes to the
oscillocope? How do I do this?

Chris

 

[Michael Black]

I tried what earlier posts said for about 20 minutes, and I have not
been able to get anything on the display. Question: The calibration
"C" bar is suppose to give a square wave, so if I pinch one probe on
it where do I put the ground probe? I tried putting the black probe
into a tiny hole.

The calibrator is a square wave, of a fixed voltage that shouldn't be
hard to miss, and I think something like about 1KHz. It's purpose
is to provide a known voltage for you to quickly check things. It
also comes in handy to make sure things are working right.

Since it's built into the scope, it shares the ground with the rest
of the scope circuitry. Hence, you don't need to do anything with
the ground lead of the probe. Touching the actual probe to the
calibrator out should show something on the scope. If not, then
either the calibrator is bad, or the scope is bad.

Anyway, two UNCAL came one. The manual says the UNCAL lights indicate:

1)Light indicates that the VAR control is not in the calibrated
position. [They are talking about the fine knob on the Volts/div.]

2) Light that indicates when the VAR Time/Div control is out of the
calibrated detent and the horizontal sweep rate is uncalibrated. [They
are talking about the fine knob on the A and B Time/Div and Delay Time
knob.]

I couldn't get the lights to go out.

Have you got the potentiometer part of the controls set on their
detent? There should be a spot where you feel something, and in
that position the variable controls are out of the circuit, leaving
only the stepped controls.

This isn't anything to worry about at the moment. It's not going
to mess up your ability to see a signal displayed on the scope. It
will just mean that the readings on the stepped controls aren't accurate.
I can't imagine why the lights don't go out, but neither can I imagine
that their not turning off is somehow linked to a greater problem.

Michael

 

[Chris L]

I tried for a half hour without success. Can someone review with me
where to connect the oscillocope probes. Where do I hook them up on
the scope (mine has 4 connections but only two are for channels 1 &
2). There are two other outputs but I do not know how to use them.
Next, once I know how to connect to probes to the scope, where do I
put the other two ends?

The scope now has 2 UNCAL lights come on, one for volts/div and one
for Time delay.

The "C" calibration bar on the scope should produce a step function.

Chris L.

 

[ehsjr]

I tried for a half hour without success. Can someone review with me
where to connect the oscillocope probes. Where do I hook them up on
the scope (mine has 4 connections but only two are for channels 1 &
2). There are two other outputs but I do not know how to use them.
Next, once I know how to connect to probes to the scope, where do I
put the other two ends?

The scope now has 2 UNCAL lights come on, one for volts/div and one
for Time delay.

The "C" calibration bar on the scope should produce a step function.

Chris L.

Did you get a trace when you pressed beam finder?
You do not need probes for the beam finder test.

Ed

 

[Chris L]

Did you get a trace when you pressed beam finder?
You do not need probes for the beam finder test.

Ed

No, nothing appeared

Chris L.

 

[Cliff Schuring]

Christopher,
If you are using a probe then latch the little hook on the end
on to the bar that has the listing calibrator on it. That is exactly
what it is it has a signal typically about 1 to 10 Khz square wave and
typically 100mV it will be listed in your manual. You now have signal
on the tip of the probe. If you look at the side of the probe it will
say if it is a 10X probe or 1 X probe and make sure that if it has a
switch it is not set to ground (some probes have that as an option).
With you probe attached to channel one look at the knob and see where
the setting is I don't remeber what the 465 has on it (10X and 1X
lables are pretty typical. rotate it to where the 100mV per division
or 50 mV per division are present. The little lever under the knob or
on the side should be placed first in ground position. This will allow
you to center up the trace and find it on the scope screen-- put
trigger on believe right side should be on external auto. Brighten up
the intensity so you can see the ground trace and position it in the
center of the screen with the position knob near your channel one
knob. Once this is done put the scope into AC mode this will keep any
offsets from possibly putting your trace into never never land so you
can't see it. Slowly change the time base knob and look for it to
begin flashing as you get a signal. Now take the little knob up near
the trigger and move it (I think it says trigger level) till you sync
with the calibation signal. (this sets the level above or below ground
that you think is a good triggering point and will allow the wavefrom
to sysnc. Hope this helps. (if the scope has a setup button on it then
put probe on cal bar on front of scope and hit the setup button --
following what ever it says and it will set it up for you
automatically all four probes at once)

Regards
Cliff

 

[ehsjr]

No, nothing appeared

Chris L.

If the intensity is turned all the way up, and you are holding
the beam finder button in and adjusting the vertical position
control, and that does not bring the trace on the screen, that
means your scope needs repair - something is defective. That
beam finder test does not require any input - you don't even
need probes connected.

Troubleshooting starts with checking the voltages, per the
manual.

Ed

 

[Chris L]

If the intensity is turned all the way up, and you are holding
the beam finder button in and adjusting the vertical position
control, and that does not bring the trace on the screen, that
means your scope needs repair - something is defective. That
beam finder test does not require any input - you don't even
need probes connected.

Troubleshooting starts with checking the voltages, per the
manual.

Ed- Hide quoted text -

- Show quoted text -

I tried for a half hour without success. I'll try again over the
weekend. I will do things slowly and look for a very faint trace.

Chris L

 

[Michael A. Terrell]

No, nothing appeared

Chris L.

How is "Triggering' set?


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Chris L]

How is "Triggering' set?

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

From the manual:

General
The A Trigger Generator circuit produces the trigger pulse used to
start the
Sweep Generator circuit that provides the A portion of the CRT
display. The
trigger pulse is derived from the internal trigger signal from the
vertical
deflection system, an external signal connected to the external
trigger input
connector, or a sample of the line voltage connected to the
instrument. Controls
are provided to select trigger level, slope, coupling, and source.

Fig 3.5 Detailed block diagram of the A Trigger Generator circuit.

Trigger Source
Trigger SOURCE switch S505 selects the source of the trigger signal.
The sources
available to the A Trigger Generator circuit are the signal being
displayed
(NORM), Channel 1 (CH 1), Channel 2 (CH 2), the instrument line
voltage LINE),
and external signals (EXT and EXT div 10). Emitter followers Q502,
Q504, and
Q506 provide isolation between the input to the A Trigger Circuit and
the output
of the Vertical Channel Switching Circuit.

In the LINE mode of triggering, a sample of the power line frequency
is obtained
from the secondary of the power transformer T1400 in the Low Voltage
Power
Supply circuit. The Trigger COUPLING switches should not be in the
LFREJ mode
when using the instrument line voltage as a trigger signal source.

Trigger Coupline
The Trigger COUPLING switches offer a means of accepting or rejecting
certain
components of the trigger signal. In the AC, LF REF, and HF REJ mode
of trigger
coupling, the DC component of the trigger signal is blocked by
coupling
capacitors C515 or C516. Frequency components below about 60 Hz are
attenuated
when using AC or HF REFJ coupling and below about 50kHz when using LF
REJ
coupling. The higher frequency components of the trigger signal are
passed
without attenuation. In the HF REJ mode of trigger coupling, the high
frequency
components of the trigger signal (above about 50 kHz) are attenuated,
while the
lower frequency components (between about 60 Hz and 50 kHz) are passed
without
attenuation. The DC mode of trigger coupling passes unattenuated all
signals
from DC to 200 MHz and above.

Input Source Follower
....

Paraphase Amplifier
....


The slope of the input signal that triggers the Sweep Generator
circuit is
determined by the setting of the SLOPE switch S530. When the SLOPE
switch is set
to the + position, the output signal at pin 8 of US20 is inverted with
respect
to the input signal, and the output signal at pin 9 is in phase with
respect to
the input signal. When the SLOPE switch is set to the - position, the
output
signal at pin 8 is in phase with respect to the input signal, and the
output
signal at pin 9 is inverted with respect to the input signal.

Tunnel Diode Driver
....

Trigger View Amplifier
The Trigger View Amplifier circuit amplifies a sample of the signal
present in
the A Trigger Generator circuit and passes it on to the Vertical
Output

Amplifier for display n the CRT when the TRIG VIEW pushbutton is
pressed. This
provides a method of making a quick and convenient check of the signal
being
used to trigger the oscilloscope and is intended primarily to be used
to check
the timing difference between the trigger signal and the vertical
deflection
signal.

The amplifier consists of two emitter-coupled pushpull amplifier
stages. The emitter source voltage for Q662 and Q672 is switched on
and off by the TRIG VIEW pushbutton. With the TRIG VIEW bushbutton not
pushed, the emitters of Q662 and Q672 are returned to ground through
R665. This reverse-biases the base-emitter junctions of the
transistors, preventing any loading of the A Trigger Generator
circuit. When the TRIG VIEW pushbutton is pushed, the emitters are now
returned to +15 volts through R663 and R679. This forward biases Q662
and Q672 to allow signal amplification. Trigger View Centering
adjustment R673 adjusts for correct DC balance in the circuit.

Normally, the output of the Vertical Channel Switching circuit is
applied to the input of the Delay Line. When the TRIG VIEW pushbutton
is pushed, the signal from the Vertical Channel Switching circuit is
removed and the output from the Trigger View Amplifier is applied in
its place.

Sweep and Z-Axis Logic
The Sweep and Z Axis Logic Circuit derives the logic levels necessary
to control the sequence of events associated with sweep generation and
CRT unblanking. The +A and +B GATE signals are also generated in this
circuit. Positive logic terminologies and symbologies are used in the
following explanation of circuit operation. Fig. 3-6 shows a detailed
block diagram of the Sweep and Z-Axis Logic circuits.
....
Pin3. This is the positive tunnel diode output terminal. In the AUTO
mode of operation (TRIG MODE set to AUTO) at the end of the holdoff
time period, pin 1, pin 16 and pin 19 are LO, and pin 8 is HI. This
causes the gate level at pin 3 to step LO to turn Q574 on, which
initiates a sweep.

Pin 6. This is the auto RC timing terminal. R609 and C609 determine
the amount of time between loss of trigger signal and the generation
of an auto gate at pin 3 when TRIG MODE is set to AUTO.
....

Pin 8. This is the holdoff timing terminal. The time between the end
of an individual sweep and the start of the next sweep is determined
by RC components that affect the time constant of voltage of pin 8.
The TIME/DIV control selects fixed components in the holdoff timing
circuit and the A TRIG HOLDOFF control allows a variable holdoff
setting in each position of the TIME/DIV control. When pin 8 goes HI,
pin 17 will go LO and allow the trigger tunnel diodes to fire on an
incoming signal or generate an auto gate in the Auto mode if pin 6 is
HI.

Pin 11. This terminal lights the READY light when operating in the
single sweep mode.
....
Pins 14 and 15. Single Sweep reset terminals. Pressing the SINGL SWP
pushbutton prepares the single sweep circuitry to respond to the next
triggering event. Also, this action causes the READY light to be lit.

Main Gate Comparator
Q572 and Q574 form the Main Gate Comparator and are connected as a
voltage comparator, where both transistors do not conduct at the same
time. The input signal to the stage is the positive-going trigger
signal from the A Firing Trigger TD in the A Trigger Generator
circuit. The signal at the collector of Q574 is inverted by Q588, is
connected to the Z Axis Logic Multivibrator to control CRT blanking,
and to Q584 to generate the A + GATE output signal. The signal at the
collector of Q572 connects to the base of the Main Gate Amplifier
stage (Q902) in the Sweep Generators circuit to initiate sweep
generation.

Delayed Gate Comparator
....

A Trigger TD Reset Circuit
....
Holdoff Start Circuit
....
Z Axis Logic Multivibrator
....
Delaying Sweep Latch Circuit
Q788, Q794, and Q796 form the Delaying Sweep Latch Circuit. The
circuit function is used during the three delayed sweep modes of
operation that the instrument is capable of (MIX, A INTEN, and B
DLY'D). Q938A, in the Delay Pickoff Comparator of the Delaying Sweep
Generator, is the current source for the emitters of Q794 and Q796.
Prior to the end of the delay time selected by the A TIME/DIV switch
and DELAY TIME POSITION control, Q938A is off, thereby causing both
Q794 and Q796 to be off also. The base level of Q794 sits at a more
negative level than does the base of Q796 so that when Q938A turns
on, at the delay pickoff point, Q794 will turn on and Q796 will remain
off. The resultant positive movement at the collector of Q794 is
connected to the B Trigger TD Reset Circuit.
....
B Trigger TD Reset Circuit
....

Main Sweep Holdoff Gate and Delayed Sweep Override Amplifier
....
During the delayed sweep, Q798 functions as an override amplifier. It
is possible, with the right combination of control settings, to
achieve a delayed sweep presentation where the delayed sweep would
normally want to continue running after the end of the delaying sweep.
For instance, if the TIME/DIV controls are set only 1 or 2 ranges
apart and the DELAY TIME POSITION control is set to a 8.50 setting.
Under these conditions the delaying sweep end-of-sweep pulse occurs
before the delayed sweep end-of-pulse. The positive movement on the
collector of Q588 at the time of delaying sweep end-of-sweep pulse
turns Q798 on. The negative movement on the collector of Q798 pulls
down on the collectors of Q794 and Q796, through CR793 and CR792
respectively, which in turn pulls down on the base of Q792. ...

A + GATE and B +GATE Amplifiers
Q584 and Q824 are the A +GATE and B +GATE amplifiers respectively.
They provide the +GATE output signals available at the instrument rear
panel. These output gate signals are positive-going rectangular
waveforms, approximately 5 volts in amplitude, coincident with their
respective sweep waveforms.

LOW LINE Indicator Circuit
Q1492, Q1498, and their associated circuitry monitor the unregulated
voltage in the +50 volt supply and provide a visual indication (via
the LOW LINE indicator on the front panel) when the applied line
voltage falls below the lower regulating limit selected by the
Regulating Range Selector assembly. Q1482 provides operating power to
the CRT graticule lights that is adjustable via the SCALE ILLUM
control R1480.


Sweep Generators Timing and Horizontal Display Switching
The Sweep Generators provide several sweep display modes, dependent
upon the horizontal mode selected by the HORIZ DISPLAY switch. One
sweep generator may be employed as a delay circuit for a second sweep
generator, permitting a variety of useful display modes. Before the
discussion of sweep generation, it is helpful to become familiar with
each principle mode of horizontal display and its associated sweep
generator, sweep gate and sweep display labeling. See Table 3-2 for a
list of sweep generator, sweep gate and sweep display terminology
whenever needed throughout the following sweep generators discussion.

Table 302
Horizontal Display Sweep Generator
Terminology Gate that
HORIZ DISPLAY CRT
Display Initiates
Sweep
Switch Setting
------------------------------------------------------------
Portion of Sweep Sweep
Generator
Displayed on CRT Used
for Display
A (TIME/DIV A Non-
Delaying Main
Knobs Locked)
A (TIME/DIV A
Delaying Main
Knobs Unlocked)
MIX A ( First Portion)
Delaying Main

--------------------------------------------------------------------------------------
B (Last Portion)
Non-Delaying Delayed
A INTEN A
Delaying Main

-------------------------------------------------------------------------------------
B (Intensified Portion) Non-
Delaying Delayed
B DLY'D B
Non-Delaying Delayed

(After being delayed

by Delaying Sweep)

 

[Chris L]

Can I ask for suggestions at this point?

Thanks,
Chris Lusardi