TEKTRONIX 2213A CRO Oscilloscope - XY Mode Issue - Only half a circle

[BTO]

TEKTRONIX 2213A CRO Oscilloscope - XY Mode Issue - Only half a circle

Hi Guys,
SUMMARY :
I Recently bought a C.R.O. and am in the process of testing if it all works.
I'm 50 years of age, Been into electronics as long as Dave and am not new to scopes CRO or DSO.

I suspect i actually do have an issue on this one and just wanted to bounce ideas of everyone before cracking it open for a repair.

Already searched the internet for several days on issues relating to X-Y Mode not working properly and only getting half a circle.
Most of what comes up is...
- How to get into XY Mode
- Yes i have R.T.F.M.
- What to do if having trouble getting into XY Mode
i already know all this.

I have tested my Rigol against another CRO, a Kikusui, XY Mode works perfectly as expected.
and while doing the same thing on this CRO the result is not the same

HARDWARE :
TEKTRONIX 2213A
60MHz
Dual Channel

KNOWN WORKING SCOPE (For Signal Generation)
DSO
Rigol MSO5074 (Upgraded to MSO5354)
350MHz
4 Channel
16Ch L.A.
2 Channel Signal Generator up to 25MHz

The MSO5000 will be our Known working Device
and the Tektronix will be our D.U.T.

THE PROBLEM :
X-Y MODE DOES NOT WORK AS EXPECTED (Details below)

GOAL :
to get into XY Mode and have an Oscillating Circle by Putting 1 channel on 1000 Hertz and the other channel on 10001Hertz.

TROUBLESHOOTING thus far

- Tektronix Power ON Test -  Powers Up
- Tektronix Basic Trace Test - it powers up with a trace (WE HAVE A TRACE)

- Channel 1 Signal Test - Passed , Sine Wave, 5V, 1Khz loaded successfully.
Note : also tested on Square wave and triangle waver and on various frequencies from 10Hz to 1KHz, 10KHz, 1MHz, 10MHz
Channel 1 works perfectly as expected

- Repeated same test on Channel 2 - Channel 2 works the same and as expected
- The switch from Channel 1, to Both to Channel 2  works perfectly
- Focus, Intensity, Trigger all seem to work fine
- Trace rotation has been checked and adjusted on DC to be straight

- Photo 8 shows the switch flipped to  BOTH position and both traces work
- Photo 9 shows me selecting XY Mode correctly
- Photo 11 shows,  I'm in XY Mode However....

the trace was initially to the far left and i had to adjust the Horizontal position to get it to the middle

Second issue,   the trace is not Diagonal, it's Vertical.  AM I WRONG HERE ?  it should be Vertical in XY Mode, right ?
Because XY Mode Plots Channel 1 against Channel 2

- Photo 16 Shows the problem.
XY Mode works.... sort of .
when Ch 1 on the sig gen is 1Khz and Ch 2 is 1001Hz
Half the circle behaves absolutely as it should and expected
the other side just remains as a vertical line
The vertical line is representing Ch 2 on the scope, because if i exit XY Mode and change the Amplitude Base it is Ch 2 that changes in
amplitude


SO GUYS
ANY IDEAS HERE

1. Why am i not getting a Horizontal line upon entering XY Mode
2. Why do i not have a complete circle in XY Mode
3. Why is the trace starting all the way to the left and not as a diagonal expression in the middle of the screen ?

ANY IDEAS
I'm thinking, Faulty internals that control Channel 2

ANY THOUGHTS

[BlownUpCapacitor]

I would guess really really really bad phase offset in the x-y mode?

I'm not sure....

I'll look through the service manual and report back later.

I know you have lots of experience with scopes, but it can sometimes help if you follow settings exactly as listed in manual.

CRT:
Best focus
Desired intensity

Vertical:
Both channels set to same sensitivity and correct sensitivity for x-y operation
BW limit off
Ch2 Invert off
Both Channels GND couple
Vert mode ALT

Horizontal:
X-Y mode
Horz Mode: No-dly

Trigger:
P.P. Auto Trig
Positive slope
Ch1 Trig source
Trigger Source: INT
EXT couple: AC
Varhold off: Norm

Now with these settings, use the horizontal and ch2 position controls to center the dot to the middle.

Connect signals, and set both channelsto DC couple.

What do you observe?

[BlownUpCapacitor]

After looking at schematics, check the following transistors:

Q732
Q737
Q742
Q743

They amplify the X-axis signal from CH1.

Don't pull them out. Use another scope to trace the signal from CH1 in X-Y mode. Follow the schematic on page 159 here https://w140.com/tekwiki/images/e/e5/070-4733-00.pdf

Follow the signal until it looks "wrong", maybe the wave is cut in half, or it's out of phase.

[bdunham7]

Try this:

Select the XY mode, remove any inputs and set both channels to 1V/div and GND.  There should be a dot somewhere, hopefully on the screent.  If not, use the beam finder and intensity controls to brighten and locate it.  Then adjust the CH1 and CH2 position knobs until you get the dot right in the center of the screen.  Then use the CH1 and CH2 position knobs, one at a time, to move the dot to the edges of the screen.  Can you put the dot all the way to the top/bottom and right/left?

After that, you can connect the inputs and change the input coupling from GND to DC on one channel at a time and adjusting the input gain to see if you can get a vertical or horizontal line as wide as the entire screen-or not.

[BTO]

"I know you have lots of experience with scopes, but it can sometimes help if you follow settings exactly as listed in manual."
Thank you for the initial respect, it's appreciated.
but i have indeed RTFM (and stated that in the troubleshooting), it is however possible that i have made a mistake somewhere.

so....

CRT:
Best focus                           - CONFIRMED
Desired intensity                 - CONFIRMED

Vertical:
Both channels set to same sensitivity and correct sensitivity for x-y operation - CONFIRMED
BW limit off                          - CONFIRMED OFF
Ch2 Invert off                      - CONFIRMED OFF
Both Channels GND couple  - CONFIRMED and when ground coupled there is obviously no trace
Vert mode ALT                      - CONFIRMED ALT

Horizontal:
X-Y mode - CONFIRMED (as per the picture)
Horz Mode: No-dly  - CONFIRMED delay off

Trigger:
P.P. Auto Trig            - CONFIRMED
Positive slope         - CONFIRMED
Ch1 Trig source       - CONFIRMED
Trigger Source: INT - CONFIRMED
EXT couple: AC        - CONFIRMED
Varhold off: Norm    - CONFIRMED

Now with these settings, use the horizontal and ch2 position controls to center the dot to the middle......... DONE

Connect signals, and set both channelsto DC couple.

What do you observe?
EXACTLY THE SAME THING... NO CHANGE

[BTO]

Thanks for your reply and effort.
I have done as you have asked and here are the results....

Found the trace easily.
Adjusted it to dead centre of the screen
NOW THIS PART IS INTERESTING

VERTICAL Position Adjustment
I can go all the way up the screen and off the screen by the same distance that it took to go from centre to the topo div.
i can go all the way to the bottom in the same fashion and it goes off the bottom by the same distance as from middle to bottom div.

HORIZONTAL Position Adjustment
NOW HERE WE HAVE A PROBLEM

- I can adjust horizontal to the far left and it goes off the screen by the same distance as from Middle to far left div.
- But if i go right i can't even make it 1 entire division to the right but instead, only 3 sub divisions
Interesting

[BTO]

Firstly thank you again.
and .. Ahh yes, this is what i suspected,  We're gonna need to operate

I agree with what you're saying, it does sound like an unintended phase offset.
OK, ill get onto cracking it open and let you know what happens.

Ill be in touch

[bdunham7]

HORIZONTAL Position Adjustment
NOW HERE WE HAVE A PROBLEM

- I can adjust horizontal to the far left and it goes off the screen by the same distance as from Middle to far left div.
- But if i go right i can't even make it 1 entire division to the right but instead, only 3 sub divisions
Interesting

I just want to make sure I have this right:

1.  In YT (normal) operation with 1 or 2 traces you get a more or less normal display all the way across the screen.
2.  In XY operation, you get the more or less expected Lissajous figure on the right side of the screen but the trace refuses to draw properly past the center line to the left.
3.  Using the horizontal position knobs to move the no-input dot in XY mode, you can get the dot to move to the left (where the XY trace wouldn't go) but can't move it to the right (where the XY trace did go).

If that's correct, that's quite interesting.  If not, please clarify as needed.

[BTO]

UPDATE :
In line with the idea that the problem here is a Phase Offset due to faulty Tranny's

I have set my 2 known working Signal Generators Each to 5V , 1KHz, No offset and No Phase Offset.
IN YT Mode
Basically.. The traces line up
and for comparison i have adjusted the vertical position for Ch1, / Ch 2 comparison.

the pictures show the results.
So therefore the offset seems to be only affecting XY Mode

[BTO]

HORIZONTAL Position Adjustment
NOW HERE WE HAVE A PROBLEM

- I can adjust horizontal to the far left and it goes off the screen by the same distance as from Middle to far left div.
- But if i go right i can't even make it 1 entire division to the right but instead, only 3 sub divisions
Interesting

I just want to make sure I have this right:

1.  In YT (normal) operation with 1 or 2 traces you get a more or less normal display all the way across the screen.
2.  In XY operation, you get the more or less expected Lissajous figure on the right side of the screen but the trace refuses to draw properly past the center line to the left.
3.  Using the horizontal position knobs to move the no-input dot in XY mode, you can get the dot to move to the left (where the XY trace wouldn't go) but can't move it to the right (where the XY trace did go).

If that's correct, that's quite interesting.  If not, please clarify as needed.

1.  CORRECT, it does seem to be the case
2. Yep that's correct
3. Yes that's also correct

let's also consider that when i enter XY Mode, i'm expecting the trace to be
1. in the centre of the screen
2. To be diagonal, from bottom left to top right while bissecting the mid point of the screen.  that doesn't happen. Instead
   when entering XY Mode i get a vertical line on the Middle vertical graticule

Yes it's very interesting, I personally have never seen this in some 45 years

[bdunham7]

Your diagonal line should be there in XY if both inputs have the same signal, otherwise you'll get a pattern (or blur) if the signal aren't the same or a dot if they're zero.  In the case of just an X signal, you get a horizontal line and if just a Y signal a vertical one. 

My first thought is that you have a logic or switching problem.  Can you verify that only the knob marked "Horizontal Position" moves that no-signal dot and the CH1/X position indicator has no effect?  Also, just for the heck of it try cycling the timebase switch in and out of XY mode a few dozen times.

[BTO]

HORIZONTAL Position Adjustment
NOW HERE WE HAVE A PROBLEM

- I can adjust horizontal to the far left and it goes off the screen by the same distance as from Middle to far left div.
- But if i go right i can't even make it 1 entire division to the right but instead, only 3 sub divisions
Interesting

I just want to make sure I have this right:

1.  In YT (normal) operation with 1 or 2 traces you get a more or less normal display all the way across the screen.
2.  In XY operation, you get the more or less expected Lissajous figure on the right side of the screen but the trace refuses to draw properly past the center line to the left.
3.  Using the horizontal position knobs to move the no-input dot in XY mode, you can get the dot to move to the left (where the XY trace wouldn't go) but can't move it to the right (where the XY trace did go).

If that's correct, that's quite interesting.  If not, please clarify as needed.

Let me do this with photo's step by step
so we know that both channels in YT Mode work normally as expected
we know that currently my Known Working Rigol Scope is pumping out waveforms over 2 channels and each one is set to 1KHz, 5V
Photo 20 represents 2 WAVEFORMS overlapped at 1KHz

Photo 21 - represents me chaning Ch2 Waveform to 1001Hz while leaving Ch 1 waveform at 1kHz in YT Mode
Photo 22 - Shows both time bases (both are set to 1x probe , 1 Volt per Div.

Photo 23 - Shows the immediate result by doing nothing else other than switching Horizontal control to XY Mode
as you can see the trace is all the way to the left

Photo 24 - i now adjust Horizontal Position to bring it to the centre
As you can see, there is no Diagonal line, but it starts Horizontal

Photo 25 - i now adjust the CH1 Volts/Div. from 1 to
0.5  this shows no change
0.2 shows the result in Photo 25
Previously i had more of the circle

Photo 26 - shows what happens when i go from 0.2 to 0.1
Now.. this seems like a big jump and it wasn't like this last time i turned the scope on this morning .

[BTO]

Your diagonal line should be there in XY if both inputs have the same signal, otherwise you'll get a pattern (or blur) if the signal aren't the same or a dot if they're zero.  In the case of just an X signal, you get a horizontal line and if just a Y signal a vertical one. 

My first thought is that you have a logic or switching problem.  Can you verify that only the knob marked "Horizontal Position" moves that no-signal dot and the CH1/X position indicator has no effect?  Also, just for the heck of it try cycling the timebase switch in and out of XY mode a few dozen times.

CORRECT
IF i am in XY Mode (which i am)
IF both input signals are identical (they are , 5V, 1kHz)
i should get a diagonal line,  I do not

as for the Horizontal Position knob
yes, CONFIRMED, as per the pictures, i'm ONLY moving the Hor. Position knob, and nothing else

as for the , for the hell of it,
I've done that tonnes of times

[bdunham7]

yes, CONFIRMED, as per the pictures, i'm ONLY moving the Hor. Position knob, and nothing else

I wanted to confirm that if you move the CH1 position knob it has no effect at all in XY mode?

Also, for photos 24 and up, did you put the signal generators back to 1.000kHz each or did you leave CH2 a 1.001 kHz?

Anyway, it looks to me like you'll find your issue either near Q732/Q737 in the center of schematic p. 5 or perhaps near U350 in the upper right corner of schematic p. 3.  I think your horizontal amp and control are fine, something in the X amplifier circuit is biasing it all the way negative.  You might want to check that the XY and (not)XY (the XY with a bar above it) signals are switched correctly first, I've no idea what would happen if one of them was incorrect.

 

[BTO]

yes, CONFIRMED, as per the pictures, i'm ONLY moving the Hor. Position knob, and nothing else

I wanted to confirm that if you move the CH1 position knob it has no effect at all in XY mode?

Also, for photos 24 and up, did you put the signal generators back to 1.000kHz each or did you leave CH2 a 1.001 kHz?

Anyway, it looks to me like you'll find your issue either near Q732/Q737 in the center of schematic p. 5 or perhaps near U350 in the upper right corner of schematic p. 3.  I think your horizontal amp and control are fine, something in the X amplifier circuit is biasing it all the way negative.  You might want to check that the XY and (not)XY (the XY with a bar above it) signals are switched correctly first, I've no idea what would happen if one of them was incorrect.

as for the photo's
only photo 21 has 2 different frequencies

Photo 20 and 22 - to the last one are identical 5V, 1kHz

as for Ch1 "Position" Knob
This knob has NO EFFECT in XY Mode

Ch 2 "Position" Knob allows me to move the trace up and down

HANG ON.... HOLD THE PHONE
Ch1 Position knob DOES HAVE AN EFFECT

it would appear that if the position knob
As per Photo 27
if it's set all the way to the right THE CIRCLE IS SMALLER

As per Photo 28
if it's set all the way to the right THE CIRCLE IS BIGGER

but if the position knob does not affect the vertical movement in any way

[BlownUpCapacitor]

I think I see the problem here now.

Something in channel 1's X-axis amplifier is not conducting the negative cycle of the signal. This is a typical behavior of semi-conductors. Check those, especially transistors and diodes. Hopefully, an IC isn't cooked. CR732 is of suspect.

Looking at block diagrams, this issue is happening in the trigger circuit, or block [3], or the horizontal amp. [5].

The detailed block diagram on tek wiki is cut in half, but I can determine that Q732 and Q737 are of very high suspect.

All other functions work fine yes? If anything other than Q737 and Q732 are faulty, then one or more other functions wouldn't work properly, ei: Holdoff, trigger, delay sweep.

I recommend you pull those transistors and test them, preferably in a curve tracer such as the 7,5CT1N, 576, 577, etc. If you don't have these, a simple diode check should suffice, though this is not as reliable as a true transistor curve tracer. Maybe this is a good time to build your own transistor curve tracer if you lack one. W2AEW has a YT video making a DIY cirve tracer that I find works as well as my 5CT1N, without all the extra controls of course.

If however, these transistors test fine, check the components surrounding these transistors. I have included a small screenshot of the surrounding circuitry.

Report back. If this doesn't find the problem, the issue is I think a lot deeper than expected.

[Note: You said that the horz pos control is also not working well in X-Y, this indicates a problem in the circuitry shown in the image titled "EVIDENCE 3". Hopefully only the above-mentioned is needed]

Also, check the waveforms provided in the service manual for section 5 of the circuitry. RTFM, though you already did, but maybe not checked waveforms. I'm not sure.

Page 157 for waveforms, page 159 for test points.

https://w140.com/tekwiki/images/e/e5/070-4733-00.pdf

[BTO]

I think I see the problem here now.

Something in channel 1's X-axis amplifier is not conducting the negative cycle of the signal. This is a typical behavior of semi-conductors. Check those, especially transistors and diodes. Hopefully, an IC isn't cooked. CR732 is of suspect.

Looking at block diagrams, this issue is happening in the trigger circuit, or block [3], or the horizontal amp. [5].

The detailed block diagram on tek wiki is cut in half, but I can determine that Q732 and Q737 are of very high suspect.

All other functions work fine yes? If anything other than Q737 and Q732 are faulty, then one or more other functions wouldn't work properly, ei: Holdoff, trigger, delay sweep.

I recommend you pull those transistors and test them, preferably in a curve tracer such as the 7,5CT1N, 576, 577, etc. If you don't have these, a simple diode check should suffice, though this is not as reliable as a true transistor curve tracer. Maybe this is a good time to build your own transistor curve tracer if you lack one. W2AEW has a YT video making a DIY cirve tracer that I find works as well as my 5CT1N, without all the extra controls of course.

If however, these transistors test fine, check the components surrounding these transistors. I have included a small screenshot of the surrounding circuitry.

Report back. If this doesn't find the problem, the issue is I think a lot deeper than expected.

[Note: You said that the horz pos control is also not working well in X-Y, this indicates a problem in the circuitry shown in the image titled "EVIDENCE 3". Hopefully only the above-mentioned is needed]

Also, check the waveforms provided in the service manual for section 5 of the circuitry. RTFM, though you already did, but maybe not checked waveforms. I'm not sure.

Page 157 for waveforms, page 159 for test points.

https://w140.com/tekwiki/images/e/e5/070-4733-00.pdf

"Something in channel 1's X-axis amplifier is not conducting the negative cycle of the signal. This is a typical behavior of semi-conductors. Check those, especially transistors and diodes."
I Agree with all this

"All other functions work fine yes?"
YES they appear to do

"Maybe this is a good time to build your own transistor curve tracer if you lack one."
PERHAPS YOU'RE RIGHT, i do lack one and this actually gets deeper.
THIS SCOPE IS A GIFT

**************************************************************************************
IF YOU'RE WATCHING.... WELCOME RILEY TO THE EEV BLOG FORUM
**************************************************************************************

So the scope is a gift for the son of one of one of my best mates.
Now... i would jump straight in , However, i think it'd be cool if Riley were involved in the repair.
He's a smart kid and he's strangely interested in retro CRO's .  he has a very basic understanding of electronics in general
so i think we'll build the curve tracer together (hell, we'll build 2) and me, i have a bucket of parts that i started to catalogue and
test a little while back, i haven't got around to my tranny's yet but when i do it'd be good to have a curve tracer

SO YEAH, SOUNDS LIKE A GOOD IDEA

Let me get together with my mates kid and we'll dive into this together and fix it
SO I CAN PROPERLY WELCOME THE KID TO ELECTRONICS

Jeez man, i wish when i was 11 (as he was) there was someone to tear apart a scope with me  LOL.
i tell you what , Kids today get the benefit of so many things ,
and... His first scope  IS A TEK
Jesus christ, My first scope (and i had to go through hell to get it) was a Kikusui

anyway... I will get onto all this
I will keep you in the loop (this won't happen today), Possibly in a week.
let me get riley invovled , we'll make a day of it and we can hopefully get this bad boy fixed.

I reckon i'm gonna enjoy this.
it's also strange that i wasn't able to find anything on this problem anywhere else.

[bdunham7]

HANG ON.... HOLD THE PHONE
Ch1 Position knob DOES HAVE AN EFFECT

it would appear that if the position knob
As per Photo 27
if it's set all the way to the right THE CIRCLE IS SMALLER

As per Photo 28
if it's set all the way to the right THE CIRCLE IS BIGGER

but if the position knob does not affect the vertical movement in any way

Hmmm.  Try changing the positions of the vertical mode switches (ADD/CHOP/ALT and CH1/CH2/BOTH) to see if there is any change.  Also, disable the signal to CH1/X temporarily and verify that whatever fragment of circle you have is due to that signal.  I think you have a channel switching problem of some sort, although I'm not sure what.  Check the XY and (not)XY signal as I said before and then start looking at everything they control.  I can't see how the CH1 position control would have that effect (or any) unless CH1 is not getting fully disconnected from the vertical amplifier when commanded.  And since any such issues would cause big problems in other modes, this particular issue (but perhaps not all of them) is likely related to the control of U130 by the XY logic line through S550, U540 and related nearby parts.

[BlownUpCapacitor]

Glad to see people actually encouraging the young generation into electronics. My parents don't support my hobby, seeing how absolutely messy my room was because of my hobby.

I would always be working on a project, and thus my room was very messy.

Anyway, here is the video link I was talking about for the curve tracer if you haven't found it already: https://youtu.be/ZOLLoa2fH24?si=mmftnMvwxKHUefYj

The nice thing about this that the 5CT1N doesn't have is that the frequency is adjustable.

You can't raise the frequency in the 5CT1N much higher than 60Hz as it uses an iron core transformer for the emitter-collector sweep voltage and won't work well at 1kHz.

[BTO]

HANG ON.... HOLD THE PHONE
Ch1 Position knob DOES HAVE AN EFFECT

it would appear that if the position knob
As per Photo 27
if it's set all the way to the right THE CIRCLE IS SMALLER

As per Photo 28
if it's set all the way to the right THE CIRCLE IS BIGGER

but if the position knob does not affect the vertical movement in any way

Hmmm.  Try changing the positions of the vertical mode switches (ADD/CHOP/ALT and CH1/CH2/BOTH) to see if there is any change.  Also, disable the signal to CH1/X temporarily and verify that whatever fragment of circle you have is due to that signal.  I think you have a channel switching problem of some sort, although I'm not sure what.  Check the XY and (not)XY signal as I said before and then start looking at everything they control.  I can't see how the CH1 position control would have that effect (or any) unless CH1 is not getting fully disconnected from the vertical amplifier when commanded.  And since any such issues would cause big problems in other modes, this particular issue (but perhaps not all of them) is likely related to the control of U130 by the XY logic line through S550, U540 and related nearby parts.

I CONDUCTED A VERY THOROUGH TEST ON ALL THE BUTTONS AND KNOBS AND SWITCHES
The Results are as follows

For testing purposes i have set both SIG GEN Channels to
Sine Wave
1Hz
2V

===================================================
MAIN CONTROLS
===================================================

INTENSITY      - Works as Expected and Adjusted
TRACE ROTATION - Works as Expected and Adjusted
BEAM FIND      - Works as Expected
PROBE ADJUST   - Works as Expected
FOCUS          - Works as Expected and Adjusted
POWER          - Works as Expected and Powered ON

===================================================
VERTICAL CONTROLS
===================================================
============================================================================
NOTES :

CH1 Initially set to 1 Volt/Div
CH2 Initially set to 1 Volt/Div
Timebase set to 1ms/Div  (Freq 1kHz)

Trace position without any input is set to to the 0V Midline

Changed BOTH Sig Gen Channels to 1kHz for calibration of amplitude.
Calibrated with a Square wave of 2 V Peak to peak

Then Tested basic signal input of the following waves.
- Sine
- Square
- Triangle
- DC

Performed on Both Channels
Both Channels PASSED
============================================================================

-----------------------------
VERTICAL MODE CONTROLS
-----------------------------
Switch (CH1 / BOTH / CH2)
CH1  - Works as Expected
BOTH - Works as Expected
CH2  - Works as Expected
-----------------------------
Button (BW LIMIT 10MHz) - Works as Expected
Button (CH2 Invert)     - Works as Expected
-----------------------------
Switch (ADD / ALT / CHOP)
ADD  - Works as Expected
ALT  - Works as Expected
CHOP - Works as Expected
-----------------------------

-----------------------------
CHANNEL 1 CONTROLS
-----------------------------
CH1 POSITION KNOB  - Works as Expected

CH1 VOLTS/DIV DIAL - Works as Expected
Tested with 1V, 2V, 3V, 4V, 5V
Stops at each level at the correct level

CH1 CAL AJDUSTMENT - Works as Expected

SWITCH (AC GND DC)
AC  - Works as Expected
GND - Works as Expected
DC  - Works as Expected
-----------------------------

-----------------------------
CHANNEL 2 CONTROLS
-----------------------------
CH2 POSITION KNOB  - Works as Expected

CH2 VOLTS/DIV DIAL - Works as Expected
Tested with 1V, 2V, 3V, 4V, 5V

CH2 CAL AJDUSTMENT - Works as Expected

SWITCH (AC GND DC)
AC  - Works as Expected
GND - Works as Expected
DC  - Works as Expected
-----------------------------
===================================================
HORIZONTAL CONTROLS
===================================================
-----------------------------
HORIZONTAL MODE CONTROLS
-----------------------------
Switch (NO DLY / INTENS / DLY'D)
NO DLY - Works as Expected
INTENS - Works as Expected
DLY'D  - Works as Expected
-----------------------------
-----------------------------
HORIZONTAL CONTROL
-----------------------------
HORIZONTAL POSITION KNOB - Works as Expected
HORIZONTAL SEC/DIV DIAL  - Works as Expected
X10 CAL AJDUSTMENT (PULL AND ADJUST) - Works as Expected

DELAY TIME
SWITCH 0.4ms  20us  1.0us
0.4ms - Works as Expected
20us  - Works as Expected
1.0us - Works as Expected

Multiplier Knob
< x1  to  >x50
- Works as Expected
-----------------------------
===================================================
TRIGGER CONTROLS
===================================================
VAR HOLDOFF KNOB
Norm (Anti clockwise) to Max (Clockwise) - Works as Expected
BUTTON SGL SWP reset button - Works as Expected
BUTTON P.P AUTO - Works as Expected
BUTTON NORM - Blanks the Screen
BUTTON SLOPE - Works as Expected
LEVEL KNOB - Works as Expected

INT SWITCH
CH1       - Works as Expected
VERT MODE - Works as Expected
CH2       - Works as Expected

SOURCE SWITCH
INT  - Works as Expected
LINE - Works as Expected
EXT  - Works as Expected

EXT COUPLING SWITCH
AC
DC
DC / 10

DID NOT TEST, NOT RELEVANT
=====================================================


ENTERING XY MODE

SIG GEN 1
Sine Wave
1000Hz
2V

SIG GEN 2
Sine Wave
1001Hz
2V

Changed only Time Base to XY Mode

RESULT
- NO DISPLAY ON SCREEN
(Horizontal Position Adjustment needed)

- Horizontal Position Adjusted to the centre line
- Amplitude is correct
- However there is no immediate circle or Diagonal Line


TESTED ON ANOTHER SCOPE "Entering XY Mode" as above.
My Kikusui scope on the same settings IMMEDIATELY IN XY Mode
had the full circle in the centre without adjustment needed

when changed to YT Mode, Diagonal Line appeared.
that doesn't happen on this scope

From this position
- REMOVED CHANNEL 1 SIGNAL CABLE
no change - 2V Vertical signal remains

REPLACED Ch1 Cable
- REMOVED CHANNEL 2 SIGNAL CABLE
- 2V Vertical signal disappears and becomes a single dot

Those results occur regardless of whether the switch is in
CH1 , Both, Ch2 Mode

FROM HERE
Channel 2 Dial reacts and changes the amplitude accordingly

Channel 1 - I need to change from 1V/Div  to at least 100mV/Div
        Before i can see only a small semicircle

        If i change from 100mV/Div  to 50mV/Div the Semi Circle shoots out
        disproportionately to the voltage change.

at 100mV the semi circle extends out by 1/2 a Division
at 50mV the semi circle extends out beyond 5 divisions, specifically 9.5 divisions

None of this was required on my working Kikusui scope.

So it would appear
- The Main controls seem to work
- Ch 1 controls seem to work correctly
- Ch 2 controls seem to work correctly
- the scaling seems to work and be on par and correct
- Trigger controls seem to work
- The front end inputs seem to work
- the selector for Ch1 , 2 and Both seem to work perfectly

the problem only seems to occur when entering XY Mode
and when an input is removed, there is no Horizontal line
and there is an obvious offset of 5 divisions to the left

[bdunham7]

Try changing the vertical mode controls as I suggested while it is in the XY mode with the semicircle showing.  Those controls should have no effect on XY mode, but if they do it may provide some clue as to where the issue is.  Your observation that the CH1/X position knob had some effect is one such clue, but I don't know what to make of it yet.

[BTO]

HANG ON.... HOLD THE PHONE
Ch1 Position knob DOES HAVE AN EFFECT

it would appear that if the position knob
As per Photo 27
if it's set all the way to the right THE CIRCLE IS SMALLER

As per Photo 28
if it's set all the way to the right THE CIRCLE IS BIGGER

but if the position knob does not affect the vertical movement in any way

Hmmm.  Try changing the positions of the vertical mode switches (ADD/CHOP/ALT and CH1/CH2/BOTH) to see if there is any change.  Also, disable the signal to CH1/X temporarily and verify that whatever fragment of circle you have is due to that signal.  I think you have a channel switching problem of some sort, although I'm not sure what.  Check the XY and (not)XY signal as I said before and then start looking at everything they control.  I can't see how the CH1 position control would have that effect (or any) unless CH1 is not getting fully disconnected from the vertical amplifier when commanded.  And since any such issues would cause big problems in other modes, this particular issue (but perhaps not all of them) is likely related to the control of U130 by the XY logic line through S550, U540 and related nearby parts.

I don't think it's a switching issue
with equal input signals at 1kHz , 2V , Sine Wave (and other signals)
both channels detect the signals
and i am able to switch between Ch1 and 2 independently as well as enabling BOTH, i can also ADD, Chop and ALT without issue.
ADD does double the Amplitude as expected

Most everything seems to work and when changing between Amplitudes and time bases, it seems to change accordingly with either
very little drift or none at all.
Most everything seems O.K. Until you throw it into XY Mode
and the other 2 things
there is no Entire Circle in XY Mode
There is never a diagonal line
there is never a Horizontal line when one input is taken out
and in XY Mode it never starts in the centre of the screen as expected

[BTO]

Glad to see people actually encouraging the young generation into electronics. My parents don't support my hobby, seeing how absolutely messy my room was because of my hobby.

I would always be working on a project, and thus my room was very messy.

Anyway, here is the video link I was talking about for the curve tracer if you haven't found it already: https://youtu.be/ZOLLoa2fH24?si=mmftnMvwxKHUefYj

The nice thing about this that the 5CT1N doesn't have is that the frequency is adjustable.

You can't raise the frequency in the 5CT1N much higher than 60Hz as it uses an iron core transformer for the emitter-collector sweep voltage and won't work well at 1kHz.

"Glad to see people actually encouraging the young generation into electronics."
Thank you mate, well i have a tradition to uphold , don't i ? Like the rest of us
and also i like this kid, he seems like he'll pick it up

"My parents don't support my hobby, seeing how absolutely messy my room was because of my hobby."
LMFAO
Don't tempt me to show you a picture of my lab.
Messy bench is what we do ,  No matter how clean you get it, 2 days later it'll have something on it.

thanks for the video link, i will get onto it

[RAPo]

I also had a half moon on my Tek2225, see this thread.
In the end it appeared to be a loose connection.
Maybe that thread gives you some pointers.

[BTO]

I also had a half moon on my Tek2225, see this thread.
In the end it appeared to be a loose connection.
Maybe that thread gives you some pointers.

Thank you, i'll check it out right away,
Logically.. it does appear
Given that all the buttons are working
and scaling seems to be ok
it does appear that there is some bad connection on the Channel 2 side of things