TEKTRONIX 2213A CRO Oscilloscope - XY Mode Issue - Only half a circle - Page 1
Forum section: electronics / repair

author: BTO
author_rank: Frequent Contributor
timestamp: February 14, 2024, 11:57:00 am
content: TEKTRONIX 2213A CRO Oscilloscope - XY Mode Issue - Only half a circleHi 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 Modei 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 sameHARDWARE :TEKTRONIX 2213A60MHzDual ChannelKNOWN WORKING SCOPE(For Signal Generation)DSORigol MSO5074 (Upgraded to MSO5354)350MHz4 Channel16Ch L.A.2 Channel Signal Generator up to 25MHzThe MSO5000 will be our Known working Deviceand 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.TROUBLESHOOTINGthus 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, 10MHzChannel 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 middleSecond 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 1001HzHalf the circle behaves absolutely as it should and expectedthe other side just remains as a vertical lineThe 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 inamplitudeSO GUYSANY IDEAS HERE1. Why am i not getting a Horizontal line upon entering XY Mode2. Why do i not have a complete circle in XY Mode3. Why is the trace starting all the way to the left and not as a diagonal expression in the middle of the screen ?ANY IDEASI'm thinking, Faulty internals that control Channel 2ANY THOUGHTS

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 14, 2024, 07:11:24 pm
content: 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 cansometimeshelp if you follow settings exactly as listed in manual.CRT:Best focusDesired intensityVertical:Both channels set to same sensitivity and correct sensitivity for x-y operationBW limit offCh2 Invert offBoth Channels GND coupleVert mode ALTHorizontal:X-Y modeHorz Mode: No-dlyTrigger:P.P. Auto TrigPositive slopeCh1 Trig sourceTrigger Source: INTEXT couple: ACVarhold off: NormNow 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?

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 14, 2024, 07:36:41 pm
content: After looking at schematics, check the following transistors:Q732Q737Q742Q743They 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 herehttps://w140.com/tekwiki/images/e/e5/070-4733-00.pdfFollow the signal until it looks "wrong", maybe the wave is cut in half, or it's out of phase.

author: bdunham7
author_rank: Super Contributor
timestamp: February 14, 2024, 07:46:20 pm
content: 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.

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 02:01:56 am
content: "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 - CONFIRMEDDesired intensity - CONFIRMEDVertical:Both channels set to same sensitivity and correct sensitivity for x-y operation - CONFIRMEDBW limit off - CONFIRMED OFFCh2 Invert off - CONFIRMED OFFBoth Channels GND couple - CONFIRMED and when ground coupled there is obviously no traceVert mode ALT - CONFIRMED ALTHorizontal:X-Y mode - CONFIRMED (as per the picture)Horz Mode: No-dly - CONFIRMED delay offTrigger:P.P. Auto Trig - CONFIRMEDPositive slope - CONFIRMEDCh1 Trig source - CONFIRMEDTrigger Source: INT - CONFIRMEDEXT couple: AC - CONFIRMEDVarhold off: Norm - CONFIRMEDNow with these settings, use the horizontal and ch2 position controls to center the dot to the middle......... DONEConnect signals, and set both channelsto DC couple.What do you observe?EXACTLY THE SAME THING... NO CHANGE

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 02:11:34 am
content: 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 screenNOW THIS PART IS INTERESTINGVERTICAL Position AdjustmentI 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 AdjustmentNOW 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 divisionsInteresting

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 02:13:42 am
content: Firstly thank you again.and .. Ahh yes, this is what i suspected, We're gonna need to operateI 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

author: bdunham7
author_rank: Super Contributor
timestamp: February 15, 2024, 02:59:04 am
content: Quote from: BTO on February 15, 2024, 02:11:34 amI 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 therightside of the screen but the trace refuses to draw properly past the center line to theleft.3. Using the horizontal position knobs to move the no-input dot in XY mode, you can get the dot to move to theleft(where the XY tracewouldn'tgo) but can't move it to theright(where the XY tracedidgo).If that's correct, that's quite interesting. If not, please clarify as needed.

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 03:16:30 am
content: UPDATE :In line with the idea that the problem here is a Phase Offset due to faulty Tranny'sI have set my 2 known working Signal Generators Each to 5V , 1KHz, No offset and No Phase Offset.IN YT ModeBasically.. The traces line upand 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

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 03:33:52 am
content: Quote from: bdunham7 on February 15, 2024, 02:59:04 am1. CORRECT, it does seem to be the case2. Yep that's correct3. Yes that's also correctlet's also consider that when i enter XY Mode, i'm expecting the trace to be1. in the centre of the screen2. To be diagonal, from bottom left to top right while bissecting the mid point of the screen. that doesn't happen. Insteadwhen entering XY Mode i get a vertical line on the Middle vertical graticuleYes it's very interesting, I personally have never seen this in some 45 years

author: bdunham7
author_rank: Super Contributor
timestamp: February 15, 2024, 03:51:03 am
content: 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.

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 03:55:17 am
content: Quote from: bdunham7 on February 15, 2024, 02:59:04 amLet me do this with photo's step by stepso we know that both channels in YT Mode work normally as expectedwe know that currently my Known Working Rigol Scope is pumping out waveforms over 2 channels and each one is set to 1KHz, 5VPhoto 20 represents 2 WAVEFORMS overlapped at 1KHzPhoto 21 - represents me chaning Ch2 Waveform to 1001Hz while leaving Ch 1 waveform at 1kHz in YT ModePhoto 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 Modeas you can see the trace is all the way to the leftPhoto 24 - i now adjust Horizontal Position to bring it to the centreAs you can see, there is no Diagonal line, but it starts HorizontalPhoto 25 - i now adjust the CH1 Volts/Div. from 1 to0.5 this shows no change0.2 shows the result in Photo 25Previously i had more of the circlePhoto 26 - shows what happens when i go from 0.2 to 0.1Now.. this seems like a big jump and it wasn't like this last time i turned the scope on this morning .

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 04:14:18 am
content: Quote from: bdunham7 on February 15, 2024, 03:51:03 amCORRECTIF 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 notas for the Horizontal Position knobyes, CONFIRMED, as per the pictures, i'm ONLY moving the Hor. Position knob, and nothing elseas for the , for the hell of it,I've done that tonnes of times

author: bdunham7
author_rank: Super Contributor
timestamp: February 15, 2024, 04:38:19 am
content: Quote from: BTO on February 15, 2024, 04:14:18 amI 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.

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 05:13:52 am
content: Quote from: bdunham7 on February 15, 2024, 04:38:19 amas for the photo'sonly photo 21 has 2 different frequenciesPhoto 20 and 22 - to the last one are identical 5V, 1kHzas for Ch1 "Position" KnobThis knob has NO EFFECT in XY ModeCh 2 "Position" Knob allows me to move the trace up and downHANG ON.... HOLD THE PHONECh1 Position knob DOES HAVE AN EFFECTit would appear that if the position knobAs per Photo 27if it's set all the way to the right THE CIRCLE IS SMALLERAs per Photo 28if it's set all the way to the right THE CIRCLE IS BIGGERbut if the position knob does not affect the vertical movement in any way

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 15, 2024, 05:58:53 am
content: 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 , or the horizontal amp. .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

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 06:24:38 am
content: Quote from: BlownUpCapacitor on February 15, 2024, 05:58:53 am"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 generalso 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 andtest 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 tracerSO YEAH, SOUNDS LIKE A GOOD IDEALet me get together with my mates kid and we'll dive into this together and fix itSO I CAN PROPERLY WELCOME THE KID TO ELECTRONICSJeez 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 TEKJesus christ, My first scope (and i had to go through hell to get it) was a Kikusuianyway... I will get onto all thisI 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.

author: bdunham7
author_rank: Super Contributor
timestamp: February 15, 2024, 06:31:18 am
content: Quote from: BTO on February 15, 2024, 05:13:52 amHmmm. 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.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 15, 2024, 06:38:58 am
content: 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=mmftnMvwxKHUefYjThe 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.

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 03:52:36 pm
content: Quote from: bdunham7 on February 15, 2024, 06:31:18 amI CONDUCTED A VERY THOROUGH TEST ON ALL THE BUTTONS AND KNOBS AND SWITCHESThe Results are as followsFor testing purposes i have set both SIG GEN Channels toSine Wave1Hz2V===================================================MAIN CONTROLS===================================================INTENSITY - Works as Expected and AdjustedTRACE ROTATION - Works as Expected and AdjustedBEAM FIND - Works as ExpectedPROBE ADJUST - Works as ExpectedFOCUS - Works as Expected and AdjustedPOWER - Works as Expected and Powered ON===================================================VERTICAL CONTROLS===============================================================================================================================NOTES :CH1 Initially set to 1 Volt/DivCH2 Initially set to 1 Volt/DivTimebase set to 1ms/Div (Freq 1kHz)Trace position without any input is set to to the 0V MidlineChanged BOTH Sig Gen Channels to 1kHz for calibration of amplitude.Calibrated with a Square wave of 2 V Peak to peakThen Tested basic signal input of the following waves.- Sine- Square- Triangle- DCPerformed on Both ChannelsBoth Channels PASSED============================================================================-----------------------------VERTICAL MODE CONTROLS-----------------------------Switch (CH1 / BOTH / CH2)CH1 - Works as ExpectedBOTH - Works as ExpectedCH2 - Works as Expected-----------------------------Button (BW LIMIT 10MHz) - Works as ExpectedButton (CH2 Invert) - Works as Expected-----------------------------Switch (ADD / ALT / CHOP)ADD - Works as ExpectedALT - Works as ExpectedCHOP - Works as Expected----------------------------------------------------------CHANNEL 1 CONTROLS-----------------------------CH1 POSITION KNOB - Works as ExpectedCH1 VOLTS/DIV DIAL - Works as ExpectedTested with 1V, 2V, 3V, 4V, 5VStops at each level at the correct levelCH1 CAL AJDUSTMENT - Works as ExpectedSWITCH (AC GND DC)AC - Works as ExpectedGND - Works as ExpectedDC - Works as Expected----------------------------------------------------------CHANNEL 2 CONTROLS-----------------------------CH2 POSITION KNOB - Works as ExpectedCH2 VOLTS/DIV DIAL - Works as ExpectedTested with 1V, 2V, 3V, 4V, 5VCH2 CAL AJDUSTMENT - Works as ExpectedSWITCH (AC GND DC)AC - Works as ExpectedGND - Works as ExpectedDC - Works as Expected-----------------------------===================================================HORIZONTAL CONTROLS===================================================-----------------------------HORIZONTAL MODE CONTROLS-----------------------------Switch (NO DLY / INTENS / DLY'D)NO DLY - Works as ExpectedINTENS - Works as ExpectedDLY'D - Works as Expected----------------------------------------------------------HORIZONTAL CONTROL-----------------------------HORIZONTAL POSITION KNOB - Works as ExpectedHORIZONTAL SEC/DIV DIAL - Works as ExpectedX10 CAL AJDUSTMENT (PULL AND ADJUST) - Works as ExpectedDELAY TIMESWITCH 0.4ms 20us 1.0us0.4ms - Works as Expected20us - Works as Expected1.0us - Works as ExpectedMultiplier Knob< x1 to >x50- Works as Expected-----------------------------===================================================TRIGGER CONTROLS===================================================VAR HOLDOFF KNOBNorm (Anti clockwise) to Max (Clockwise) - Works as ExpectedBUTTON SGL SWP reset button - Works as ExpectedBUTTON P.P AUTO - Works as ExpectedBUTTON NORM - Blanks the ScreenBUTTON SLOPE - Works as ExpectedLEVEL KNOB - Works as ExpectedINT SWITCHCH1 - Works as ExpectedVERT MODE - Works as ExpectedCH2 - Works as ExpectedSOURCE SWITCHINT - Works as ExpectedLINE - Works as ExpectedEXT - Works as ExpectedEXT COUPLING SWITCHACDCDC / 10DID NOT TEST, NOT RELEVANT=====================================================ENTERING XY MODESIG GEN 1Sine Wave1000Hz2VSIG GEN 2Sine Wave1001Hz2VChanged only Time Base to XY ModeRESULT- 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 LineTESTED ON ANOTHER SCOPE "Entering XY Mode" as above.My Kikusui scope on the same settings IMMEDIATELY IN XY Modehad the full circle in the centre without adjustment neededwhen changed to YT Mode, Diagonal Line appeared.that doesn't happen on this scopeFrom this position- REMOVED CHANNEL 1 SIGNAL CABLEno change - 2V Vertical signal remainsREPLACED Ch1 Cable- REMOVED CHANNEL 2 SIGNAL CABLE- 2V Vertical signal disappears and becomes a single dotThose results occur regardless of whether the switch is inCH1 , Both, Ch2 ModeFROM HEREChannel 2 Dial reacts and changes the amplitude accordinglyChannel 1 - I need to change from 1V/Div to at least 100mV/DivBefore i can see only a small semicircleIf i change from 100mV/Div to 50mV/Div the Semi Circle shoots outdisproportionately to the voltage change.at 100mV the semi circle extends out by 1/2 a Divisionat 50mV the semi circle extends out beyond 5 divisions, specifically 9.5 divisionsNone 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 perfectlythe problem only seems to occur when entering XY Modeand when an input is removed, there is no Horizontal lineand there is an obvious offset of 5 divisions to the left

author: bdunham7
author_rank: Super Contributor
timestamp: February 15, 2024, 03:57:39 pm
content: Try changing the vertical mode controls as I suggestedwhile it is in the XY modewith the semicircle showing. Those controlsshouldhave 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.

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 03:59:35 pm
content: Quote from: bdunham7 on February 15, 2024, 06:31:18 amI don't think it's a switching issuewith equal input signals at 1kHz , 2V , Sine Wave (and other signals)both channels detect the signalsand 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 expectedMost everything seems to work and when changing between Amplitudes and time bases, it seems to change accordingly with eithervery little drift or none at all.Most everything seems O.K. Until you throw it into XY Modeand the other 2 thingsthere is no Entire Circle in XY ModeThere is never a diagonal linethere is never a Horizontal line when one input is taken outand in XY Mode it never starts in the centre of the screen as expected

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 04:02:18 pm
content: Quote from: BlownUpCapacitor on February 15, 2024, 06:38:58 am"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 usand 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."LMFAODon'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

author: RAPo
author_rank: Super Contributor
timestamp: February 15, 2024, 04:12:53 pm
content: I also had a half moon on my Tek2225, see thisthread.In the end it appeared to be a loose connection.Maybe that thread gives you some pointers.

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 04:24:35 pm
content: Quote from: RAPo on February 15, 2024, 04:12:53 pmThank you, i'll check it out right away,Logically.. it does appearGiven that all the buttons are workingand scaling seems to be okit does appear that there is some bad connection on the Channel 2 side of things

author: BTO
author_rank: Frequent Contributor
timestamp: February 15, 2024, 04:34:10 pm
content: Quote from: RAPo on February 15, 2024, 04:12:53 pmI had a look at your issue.My one appears to be identical, Almost.Your semi circle even appears on the same side.the only difference is, You adjusted the circle with Phase shifting, i'm doing with Frequency shifting.. but, that doesn't matter too much for the problem.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 15, 2024, 06:46:34 pm
content: I had another look at schematics again. Try fiddling with R738. It's the x-axis offset pot. Remember to back its original setting with a marker or something. If that doesn;t rectify the issue, reset it and follow the following steps.Probe pin 5 of P9705. Does it resemble the input signal from ch1?If not, probe TP350. Does it resemble the input signal?If not, desolder Q739 and power up the unit in X-Y mode without the transistor. While this transistor is out of circuit, do not switch into any other modes other than X-Y as this may damage the scope. If the problem solved?If not, resolder Q739 back in, or just replace it with generic 2N3904, then probe the emitters of U350E and U350D using differential probing.DO NOT CONNECT A GROUND LEAD TO ANY OF THESE POINT!!!Does it resemble the input signal?If not, probe the bases of Q302 and Q303 using differential probing.DO NOT CONNECT A GROUND LEAD TO ANY OF THESE POINT!!!Does it resemble the input signal?Report back.

author: BTO
author_rank: Frequent Contributor
timestamp: February 17, 2024, 09:49:49 am
content: Quote from: BlownUpCapacitor on February 15, 2024, 06:46:34 pmFIRSTLYShit... I blew up my scopeNo... Not really .Yes i understand the dangers of mains referencing the ground reference of the scope...... DON'T WORRY ABOUT IT. I'm aware of it.- Now i do not have a differential probe- However.. i do have a handheld Hantek Scope which is "Floating", i can charge it up on Battery power and use itto conduct the tests.FOR THE BENEFIT OF NEWBIES READING THIS AND WONDERING"What the Hell are they on about ?"TRAP FOR YOUNG PLAYERSSo.. Update, Young Riley will be coming next week on SaturdayUntil then i'll have a peek inside, but i do want to wait for him until we sink our teeth in

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 17, 2024, 06:52:48 pm
content: You don't need to use a handheld floating scope. Just use differential probing, by using two conventional probes.On a scope like a 2235, set the cert mode to "ADD" and set channel two to "INVERT". This will make a differential amp. So you can use a ground-referenced scope.Look at this video:https://youtu.be/DgYGRtkd9Vs?si=ZeNDvT2toklw6CCg&t=559You can use a good high bandwidth bench top scope instead of a cheap hantek here.

author: BTO
author_rank: Frequent Contributor
timestamp: February 17, 2024, 07:10:40 pm
content: Quote from: BlownUpCapacitor on February 17, 2024, 06:52:48 pmwell, i do have a high bandwidth scope, Rigol MSO5000 Series (350MHz), Although.. I'd rather not use it in this instance.is there anything inherently wrong with using the hantek , Just in case.at the end of the day it is a floating scope.If it's not earth referenced, I don't see the issue with it.Worse case scenario, something happens and the hantek gets sacrificed.

author: BTO
author_rank: Frequent Contributor
timestamp: February 24, 2024, 04:08:20 pm
content: OK, I'm backWith a great degree of difficulty, I got the C.R.O. Open.AS ADVICE FOR ANYONE ATTEMPTING THIS1. There is a screw on side of the chasis (take that out)2. Take off the Back Cover3. Initially you don't need to worry about removing the front panel cover or buttons and knobs4. The 2 hinges that hold up the legs HAVE NOTHING TO DO WITH OPENING THE SCOPE.The Housing will Slide down and out the back of it, But it will require some convincing because the friction (in my case, Caught on aroundhalf way making me think i missed a screw.Once opened, Here is what it looks like

author: BTO
author_rank: Frequent Contributor
timestamp: February 24, 2024, 04:37:37 pm
content: Quote from: BlownUpCapacitor on February 14, 2024, 07:36:41 pmSo.. I was looking for those Tranny's that you stated.AND THEN I SAW THIS and then i looked closer with my video microscope41 - is what i spotted first42 - a bit of a closer look33 and 34 are video scope viewsso... We have CRACKED JOINTSI sucked up the old solder with Solder wick and Re Soldered the Jointsthen restarted the scope, still get the same result, XY Still doesn't work,But YT DoesI've also noticed that If i feed in a Signal (say sine wave) 1kHz that's fine, But given this is a 60MHz scope.i should be able to feed in up to 60MHz and still be able to stretch out the signal (or.. Zoom in) and be able to easily see the waveform,However i can't. Even at 10MHz you can't zoom in and see the waveform as a single AC Line.

author: BTO
author_rank: Frequent Contributor
timestamp: February 24, 2024, 04:45:53 pm
content: Quote from: BlownUpCapacitor on February 14, 2024, 07:36:41 pmNow..1. I couldn't find those Tranny's yet that you listed, I've looked on the mainboard , it's not there.Now there are 2 others boards, A VERTICAL (which forms the board for the knobs ) and A HORIZONTAL (which appears to befor the Op Amp and controls and calibrations of controls) I took a few pictures of thisOn these boards, the first thing i encounter after the control knob is (What i believe is A TIMING CAPACITOR)Pretty cool.... It's a Tektronix Cap 0.019uF , 600V (Hard to Find)Now, one of these caps is questionable the other seem highly bloated , I'm inclined to replace them.it's the Ch2 cap that seems bloated the most.

author: BTO
author_rank: Frequent Contributor
timestamp: February 24, 2024, 04:51:28 pm
content: Quote from: BlownUpCapacitor on February 14, 2024, 07:36:41 pmHere is the Channel 1 Cap (Picture 37)and 38 is the Channel 2 CapNow in the process of looking around (Picture 35) shows that i noticed voltage readings coming out of the PSU.so i decided to test them with a DMM, they were30 V DC100 V DC8.6 V DC5 V DC- 8.6 V DCThey all test pretty much spot on.

author: bdunham7
author_rank: Super Contributor
timestamp: February 24, 2024, 06:54:35 pm
content: Quote from: BTO on February 24, 2024, 04:45:53 pmThose are not electrolytic caps and are very unlikely to be bad. Besides, they are simply the AC blocking capacitors and completely irrelevant if you are using DC coupling.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 24, 2024, 07:49:36 pm
content: That blown capacitor implies that someone overloaded the input and damaged something. Most likely in the attenuator.

author: BTO
author_rank: Frequent Contributor
timestamp: February 24, 2024, 11:42:00 pm
content: Quote from: bdunham7 on February 24, 2024, 06:54:35 pmI'm confused1. the rating on them is 0.019uF which to me suggest a capacitor2. Granted i have NEVER in my life seen a Tektronix Capacitor3. when i look up the part , it's called a Timing CAPACITOR4. you yourself called it AC Blocking Capacitorso.. How is it not a capacitor ?

author: BTO
author_rank: Frequent Contributor
timestamp: February 24, 2024, 11:44:28 pm
content: Quote from: BlownUpCapacitor on February 24, 2024, 07:49:36 pmi wouldn't say it's BLOWN but i would say it's bulging.But, ok, i'll keep the attenuator in mindi now have to figure out how to remove the boards out of the scope, once i do that i have a look for that transistorthat you were referring to

author: bdunham7
author_rank: Super Contributor
timestamp: February 25, 2024, 12:06:46 am
content: Quote from: BTO on February 24, 2024, 11:42:00 pm1. Yes2. Not unusual in this era to have Tek or Fluke or HP part labels on seemingly ordinary components.3. Where are you seeing "Timing Capacitor"? These appear to me to be C2 and C52 on the attenuator board.4. Yes, according to the schematic, these are the AC blocking capacitors. 0.019uF for the early s/n, 0.022uF for the later ones.I didn't say it wasn't a capacitor, I said it isn't an electrolytic capacitor. It's listed as a "plastic" capacitor, which probably means polypropylene but IDK for sure. The later model ones do look like PP, yours are in a can so it is hard to tell. The bottom line is that they don't have the same common failure modes that an electrolytic cap might have and in any case, the scope would still work properly (in DC-coupled mode) even if the capacitors in question were shorted, open, missing or in any other state you could think of.

author: BTO
author_rank: Frequent Contributor
timestamp: February 25, 2024, 03:39:04 am
content: Quote from: bdunham7 on February 25, 2024, 12:06:46 am2 Quick pointsYou didn't say it WASN'T a capacitor.No problemI however didn't say it WAS an electrolyticWhere did i see, TIMING CAPACITOR ?here...https://www.ebay.com/itm/224560230256They don't look electrolytic and i first thought Axial.it has 1 leg going into the usual place and the other leg seems to be on the canI'm going to try and separate the 3 boards and check whatever i can and follow the schematic and then have a look around for thos Tranny's.thus far i have the housing off and can see the markings on the bottom of the Main Board, thos tranny's are not therebut i didn't expect them to be eitherso... the Search continues

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 25, 2024, 03:51:27 am
content: These "plastic capacitors" are typically used for timing applications in Tek instruments. In fact, all of the horizontal timing circuits in all the oscilloscopes I have (that are Tektronix) use this timing capacitor idea.I have included an example of a Timing Capacitor in my 7B80 horizontal sweep plug-in.And on to you not being able to find the transistor, they are hidden away inside the metal construction of the horizontal sweep camshaft.I have attached a photoshopped image of the diagram for the A4 timing board. The transistors of suspect are highlighted in red.Do not replace the "timing capacitors" on the A4 board. Those capacitors are matched and are highly unlikely to fail.These "plastic capacitors" can usually be replaced with new modern polyprop caps.

author: BTO
author_rank: Frequent Contributor
timestamp: February 25, 2024, 05:01:48 am
content: Quote from: BlownUpCapacitor on February 25, 2024, 03:51:27 am"And on to you not being able to find the transistor, they are hidden away inside the metal construction of the horizontal sweep camshaft."LOL.....OF COURSE THEY ARE !, I mean.. why wouldn't they be ? what sane person would put them in an easily accessible location LOL"Do not replace the "timing capacitors" on the A4 board. Those capacitors are matched and are highly unlikely to fail."Understood"I have attached a photoshopped image of the diagram for the A4 timing board. The transistors of suspect are highlighted in red."I owe you a cup of coffee LOL, thank you

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: February 26, 2024, 12:10:23 am
content: If those other transistors on the sweep board test fine, check Q739 on the main board. Desolder it and put the scope into X-Y mode, then power it on. DO NOT CHANGE TO ANY OTHER FUNCTION OTHER THAN XY with this transistor removed.If that doesn't rectify the issue, report back.

author: BTO
author_rank: Frequent Contributor
timestamp: February 26, 2024, 08:08:06 am
content: Quote from: BlownUpCapacitor on February 26, 2024, 12:10:23 amOK, will do, Let me catchup on all the instructions thus far, I'll have a bit more time tomorrow, i'm a bit busy tonight.but i am on top of this. so bear with me for like 24 hours,its' more figuring out how to disassemble those damn 3 boards from each other.but give me 24 hours and i will report back, speak to you soon, thanks heaps for your ongoing help.

author: BTO
author_rank: Frequent Contributor
timestamp: March 20, 2024, 06:27:24 pm
content: Quote from: BTO on February 15, 2024, 03:52:36 pmI APOLOGIZE FOR BEING A STRANGER AND DROPPING OFF THE PLANETI have COVID and was sick as a dog. i'm significantly better now.so i'll get stuck into it again. I'll report back soon with the disassembly of the scope and trying to find the problem and checking out thosesuspect components .

author: BTO
author_rank: Frequent Contributor
timestamp: March 21, 2024, 04:45:52 pm
content: Quick Update,After my COVID i got back into it, the problem i'm currently having is how to separate the 4 boards,there's a Mainboard (Horizontally) then on top of that a stack of 2 other boards (horizotally),and then a front panel board (Vertically). Still can't work out how to separate these boards.I'll keep trying.

author: Miti
author_rank: Super Contributor
timestamp: March 21, 2024, 04:57:43 pm
content: TL;DR Did you try to select CH2 on CH1 BOTH CH2 switch? I remember having similar issues with my Tek 2445A.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: March 21, 2024, 06:59:39 pm
content: I don't think the channel mode switches interfere with the X-Y mode of operation if I remember from my Tek 2213.

author: Miti
author_rank: Super Contributor
timestamp: March 21, 2024, 07:00:53 pm
content: I think it does.Edit: I’ve attached a screenshot from a w2aew video on YouTube. Not the same model but something to consider.And see here the reply from Chuck Harrishttps://groups.io/g/TekScopes/topic/question_regarding_xy_mode/30854252?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,0,0,30854252

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: March 21, 2024, 10:49:13 pm
content: That's for the 24xx. I'm talking about the 22xx. My 2230 isn't affected by the vert mode switch in X-Y.

author: BTO
author_rank: Frequent Contributor
timestamp: March 22, 2024, 12:25:33 am
content: Quote from: Miti on March 21, 2024, 04:57:43 pmHow was my last comment Too Long ?As for your question, Read ALL the notes thus far as i and others have taken the time to address all this already.if you couldn't be bothered reading it all then why are you replying ? Everyone else in the forum seems to have had the patience to read it.

author: BTO
author_rank: Frequent Contributor
timestamp: March 22, 2024, 12:33:24 am
content: Quote from: Miti on March 21, 2024, 07:00:53 pmI've read and considered your comment, I don't think it is affected either in my scope.Again.. Different Model.In any case , I'm currently looking at service manuals and my current issue is how to disassemble my C.R.O.After that i can follow the trace and check out those suspect components that we spoke about (Did you take the time to read that yet though ?, Do you know what i'm referring to ?)

author: Miti
author_rank: Super Contributor
timestamp: March 22, 2024, 03:13:18 am
content: Quote from: BTO on March 22, 2024, 12:25:33 amI wasn't talking about your last comment, I was talking about the two pages that I didn't have time to read. I was just offering my experience, and as I said, I had similar (or so I remembered) experience with my (also Tektronix) scope when I tried X-Y function. I don't have to read ALL the notes, I can promise you that I will not bother you with my input from now on.Cheers,Miti

author: Miti
author_rank: Super Contributor
timestamp: March 22, 2024, 03:17:15 am
content: Quote from: BlownUpCapacitor on March 21, 2024, 10:49:13 pmI don't have a Tek 22xx to verify that, all I said was that, being a Tek, may be affected in the same way and is worth a try before going down the rabbit hole of repairing something that may not be defective. I don't get the rude reaction that the OP has to my post.

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: March 22, 2024, 06:06:57 am
content: Quote from: Miti on March 22, 2024, 03:17:15 amYou're probably right. Start simple. There are a few times I've found an issue with one of my pieces of Test Equipment, and gone full-on troubleshooting just to find out that it was just a wrong setting or something.

author: BTO
author_rank: Frequent Contributor
timestamp: March 22, 2024, 09:41:10 am
content: Quote from: Miti on March 22, 2024, 03:13:18 amOK... Let me explain it for you... (in the nicest way that i can)1. I appreciate everyone's help here2. I even appreciate your input and WILLINGNESS TO EVEN CARE TO HELP3. and you are free to give input , By all means.Dave made this site many years ago so that we may interact and enjoy electronics and i'm about the same age as dave and from the same era.But here's the thing...4. This isn't you tube , this isn't facebook where uneducated moron's attend and then have the attention span of a fish so they just say TLDR.5. On those sites, when people do say TLDR i dismiss it as,- i can respect their opinion without argument- at the same time i can see LACK OF COMMITMENT and laziness because that's what TLDR says, it says"I'm too lazy to read that entire post"6. NOW HERE'S THE POINT.Whether Hobbyist or Engineer, We are all here for 1 purpose, Because we are technical people and we either want to have fun or need a problem solved. and also to interact with out fellow Engineering buddies.Part of the troubleshooting proces and so that it's efficient is to systematically go through a problem.THAT REQUIRES A BIG LONG POST,Did you think i enjoyed going through every single button and say... "Works as expected", But.. doing that is required for good troubleshooting.Now...- your TLDR shows , firstly, that you don't actually care (so how can i expect you to help me )- Secondly, Your actual question is already a question that i answered, that everyone else already knows i have because they havefollowed the process thus far. that also tells me it's a waste of time to answer , as that's double handling.- If you're going to jump into the problem.... Again I APPRECIATE YOUR PARTICIPATION, but.... Participate !!! don't half arse it .and if you jump in, You're expected to read all the notes thus far and the progress and then submit input .Again, We are technical people here, No idiots on you tube .Now.. Just to be clear, (and please understand)1. I have no bad blood and i don't get stressed or upset, Not ever !!2. But when your sentence starts with TLDR, to me that means... You don't even care to read what i took the time to type up.So.. Feel free to participate , You are welcome to this party, and i guess there is a reason why you jumped in in the first place,and if that reason is to have fun. then let's have fun together, But.. Do me the respect of reading all the notes thus far, okBecause that's the purpose of this forum and we wouldn't be here in the first place if our mentality was TLDRthat's all i'm saying, okbut, i'm not upset with you, I just don't like my time to be wasted or my effort disrespected. Does that make senseI look forward to your reply

author: BTO
author_rank: Frequent Contributor
timestamp: March 22, 2024, 09:48:42 am
content: Quote from: Miti on March 22, 2024, 03:17:15 amLET ME ANSWER THEN1. My reaction was not rude, My reaction was appropriate.2. I understand your post and your intention, and i can confirm they are not the same. so I DID TAKE YOUR COMMENT INTO CONSIDERATION.don't think that i didn't3. Also do not make the mistake with me of assuming that i'm angry or rude. I don't do that.As stated in my previous comment to you (and i'll say it here as well) when you prefix your comment with TLDR it says to me thatyou don't care, now combine that with the fact that i already addressed what you said in an earlier post, it says you didn't even readthe history.Everyone here has read the history , and if you're going to participate in this conversation, i expect you to do what everyone else has done,that being, Put in a normal effort to read the comments. I'll put it this way..A few years back i jumped onto the , "How to hack the Rigol DS2000A Scope" post (the AKA Monster Post) , Mate.. BEFORE I EVEN RESPONDED , I read through approx 50 pages of comments, ok, Just to get up to speed with it. Granted that's an exaggerated example.but we only have 3 pages here, and the first comment is long and the others are pretty short. As a min requirement, you are expectedto have read the first comment entirely.. for contextso i'm not being rude, but if anything TLDR is a rude comment and it was your first. Can you see my point of view ?would you waste time with someone who right off the bat said "I don't really care, but i'm gonna comment anyway"what would you do ?that's my position, okbut.. No i'm not being rude to you, I'M BEING BLUNT so you don't misunderstand me. i'm doing that out of respect.

author: BTO
author_rank: Frequent Contributor
timestamp: March 22, 2024, 09:57:41 am
content: Quote from: BlownUpCapacitor on March 22, 2024, 06:06:57 amI agree with this, and before posting my post, (so i didn't look like a complete idiot LOL) i checked and re checked.and then, together we went through the troubleshooting , we have exhaused (i feel) all options that do not require me to crack open the housing.We can agree that this problem is unusual to have half a circle in X-Y mode and after examining the service manual , i agree that there issomething there that is either not disconnecting or switching , I agree with that train of thought.I have already noticed a few cold joints and broken joints (in the spirit of simplest solution first) and i have soldered them with fresh solder.Hoping to god that this would just be it, It wasn't.So even though i agree on not jumping the gun and i'm not dismissing Miti's input , i don't think we have jumped the gun anyway.,and.. without any ill will, i say this.. I also believe that if Miti read all the comments, Miti would have seen this, But instead, Miti just jumped in,had a quick look around (probably with the best intentions) and just said.. What about this ?Right, But we've already gone way past that.so My current problem is the disassembly of the unit, I have a vertical board connected to 3 Horizontal boards and i'm trying to figure outhow to get them separated in the least destructive way possible.there are a tonne of solder joints on the bottom board that i'm really hoping i don't have to desolder.My other concern is, if i do separate the boards, then (i assume) i can't test the boards........... Unless of course i put in temporary bodge wiresto hook it up (.... LOL, that'll be interesting)

author: BTO
author_rank: Frequent Contributor
timestamp: March 22, 2024, 10:02:53 am
content: Quote from: Miti on March 22, 2024, 03:17:15 amSO... MITI So after reading those replies from me, (and i say this genuinely)1. What are your thoughts2. Do you want to participate in this solution (if you do , You're welcome, but please put in the effort to read all the comments so that you canbe a productive member towards to the solution)3. Again.. I'm not upset IN THE SLIGHTEST, ok and if you want, I'm happy to start over with you, Hey... Everyone is subject to misunderstandings, that's not a problem at allso.. give me your thoughts.and.. If you want to leave , that's also ok (some people don't like to stay after these comments) I'm easy either way, and i take nothing personally either way. I just ask for mutual respect , that's all, I've been in electronics so long to know that i need to respect my fellow Electronics community and work together, so... You get a pass JUST BECAUSE YOU'RE IN ELECTRONICS, OK LOLif this was you tube...... Aww man, You don't even wanna know LMFAObut all jokes asideI have no bad blood, give m your thoughts though, ok

author: BTO
author_rank: Frequent Contributor
timestamp: March 22, 2024, 10:09:59 am
content: HEY GUYS, I HAVE AN UNRELATED QUESTION.Un related to this current thread, I have 3 C.R.O.'s that i need to fix.1. this Tek 2213A2. A BWD (Seriously cool, from the 60's i think) BWD 321 i think it was, 2 Ch , 40Mhz Jobbie3. A BWD (can't remember the model #) Single channel JobbieNow HERE IS MY QUESTION :Given that this scope is stuffing me around a bit, and i'm not backing out of it, i'm just trying to be time effective about it,Kill 3 scopes with 1 stone so to speakObviously i will start a separate thread for each scope, but...DO YOU THINK IT'S A GOOD IDEA TO LINK THOSE THREADS TO THIS THREAD, i guess what i'm asking is....would you guys like to participate in that solution as well.My thoughts on those scopes are... Probably will need cap replacements and a bit of TLC, there's no X-Y on those scopes as that stuff(wait for it.. LOL) wasn't invented yet. You know.. Back when dinosaurs walked the earthso what do you reckon, While i'm trying to figure out, how to disassemble this one, you guys want to help me on the other one's.I just figured since they were old scopes, people here may want to see that old Tech. I don't see a lot of BWD Posts here anyway,i reckon it'll be cool . and Yes Miti you are also invited if you want to come.

author: BTO
author_rank: Frequent Contributor
timestamp: March 22, 2024, 03:12:39 pm
content: UPDATE : Started a new post here for the BWD 506https://www.eevblog.com/forum/repair/bwd-506-c-r-o-repair-all-but-dead-will-it-survive/new/#newI've done some troubleshooting, I'm stuck between Faulty Secondary Side Transformer or Faulty C.R.T. . I don't know how to test the voltage on the C.R.T. or what it would it's supposed to be.Anyway.. Off to bed

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: March 22, 2024, 05:57:37 pm
content: Quote from: BTO on March 22, 2024, 03:12:39 pmIf the scope works fine except the X-Y mode, the CRT circuit is NOT the problem. Don't go poking around there. Keep focused on the horz-amp and sweep boards. Like I said, check transistors.Edit:OOOOHH OHHH! A THOUGHT JUST CAME TO MIND. Check voltages again. Not the PSU voltages, but the supply voltages on suspected circuit blocs. Maybe a negative supply voltage is not there and so the op-amp or what ever it is can't amplify the signal in the negative cycle.

author: BTO
author_rank: Frequent Contributor
timestamp: March 23, 2024, 05:09:22 am
content: Quote from: BlownUpCapacitor on March 22, 2024, 05:57:37 pm1. No No, what you're responding to is another scope, A BWD that is on another post, i was just mentioning it.I didn't want to go into detail about it here , that's why i left a link but that scope doesn't even have XY Mode. problem is there is no trace on screenas for Voltages, ok i'll check again, but i already checked the voltagesStill haven't managed to figure out how to disassemble the current Tek Scope

author: BlownUpCapacitor
author_rank: Frequent Contributor
timestamp: March 23, 2024, 06:21:18 am
content: Quote from: BTO on March 23, 2024, 05:09:22 amGo to page 6-16 in the service manual:https://w140.com/tekwiki/images/e/e5/070-4733-00.pdfRead the section of "TIMING CIRCUIT BOARD" in the "How to remove and replace stuff" section. The service manual provides very useful information.

author: BTO
author_rank: Frequent Contributor
timestamp: March 23, 2024, 07:23:48 am
content: Quote from: BlownUpCapacitor on March 23, 2024, 06:21:18 amHonestly, i wish the actual manual did name that chapter "How to remove and replaceSTUFF"i think that's a much cooler name LOLbut , no, thanks for that , i'll have a look at that , i didn't realize that was in the manual. Appreciate it.OK, here we go again