Re: 2247A occasional horizontal jitter
On Wed, Jul 12, 2023 at 12:58 AM, Alex wrote:
secondary side diodes (17 in total) marked with either ZM or ZS with MUT160
Oops, I meant to instead write "MUR160", just in case.
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Re: 2247A occasional horizontal jitter
If I understood correctly, given the suggestion that the horizontal jitter may be related to the DC power fed to the sweep circuit electronics, I am thinking that tracing the corresponding DC power supply busses with the other scope (2465B) to see if I can catch any glitches should be the next step.
As a side note, about? a year and a half ago I did replace the whole power supply board with a good working one which is completely unrestored although it seems to work perfectly. The original power supply just shut down while the scope was in use and would afterwards not power up again. Nothing obvious on the board that would ponit to a failed part. I tried replacing several electrolytic filter caps without much luck, but then was offered a whole tested and working replacement board from a member of this group so really never fund out what went wrong with it. One thing I had done on the original power supply was to replace all the secondary side diodes (17 in total) marked with either ZM or ZS with MUT160, as it is suggested as they get leaky after some time. But otherwise it was unmodified. Was actually planning to do the same on the replacement supply, once again as a precautionary measure.
Tomorrow I am going to try and sit down to review the service manual and find out what voltages are being supplied to the sweep board and where to best clip on, to start from there.
Thanks everyone for the input so far, and I will of course keep a close eye here in case any additional information or suggestions are posted.
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Re: 2247A occasional horizontal jitter
On Tue, Jul 11, 2023 at 04:49 PM, Dave_G0WBX wrote:
Sadly, that link? ? times out for
me.? :-(
Did you take it down?
Dave G8KBV.
Unfortunately the server where the video was uploaded is temporarily down due to a fire at the datacenter on a UPS. I am hoping it will be back online later tomorrow.
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Re: 2247A occasional horizontal jitter
Sadly, that link? times out for me.? :-(
Did you take it down?
Dave G8KBV.
--
Created on and sent from a Unix like PC running and using free and open source software:
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Re: 2247A occasional horizontal jitter
On Tue, Jul 11, 2023 at 12:18 AM, dxradio33 wrote:
Lighten up dude.? What supreme race do you claim to be from ? ?I do not happen to agree with your smart ass statement of "Most definitely a trigger level (jump) issue....." make any sense to you?¡±
Hope you find the issue soon, and as an aside, I will be sure to jump right in the next time you have a question.
Wow, you really must be an expert, looking at the authority of your above response, and a polite one as well. Good luck finding the power problem that makes the horizontal PLL (?!) lose its lock. Thanks for offering to jump in should I have a question. You know, we have members with strongly varying knowledgeable levels. We're all here to learn from others, or are we? Raymond
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Re: 2247A occasional horizontal jitter
Lighten up dude.? What supreme race do you claim to be from ? ?I do not happen to agree with your smart ass statement of "Most definitely a trigger level (jump) issue....." make any sense to you?¡± Hope you find the issue soon, and as an aside, I will be sure to jump right in the next time you have a question. ? ?
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From: [email protected] < [email protected]> On Behalf Of Raymond Domp Frank Sent: Monday, July 10, 2023 18:00 To: [email protected]Subject: Re: [TekScopes2] 2247A occasional horizontal jitter ? On Mon, Jul 10, 2023 at 11:44 PM, dxradio33 wrote: Looks like the horizontal PLL is losing its lock.? I still suspect power.
and
>
> But it seems to me that the lowest common denominator would be power.? I would suspect
> that sweep circuit electronics are getting a zap occasionally by a failing component (cap
> maybe).? It does not seem like there is any common thread in the horizontal sweep and vert
> amp which leads me to believe a lower layer contributor.
>
Follow Ozan's suggestion and report back. Also, read up on 'scope theory.
Does my comment "Most definitely a trigger level (jump) issue....." make any sense to you?
Raymond
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Re: 2247A occasional horizontal jitter
On Mon, Jul 10, 2023 at 11:44 PM, dxradio33 wrote:
Looks like the horizontal PLL is losing its lock.? I still suspect power.
and > > But it seems to me that the lowest common denominator would be power.? I would suspect
> that sweep circuit electronics are getting a zap occasionally by a failing component (cap
> maybe).? It does not seem like there is any common thread in the horizontal sweep and vert
> amp which leads me to believe a lower layer contributor.
>
Follow Ozan's suggestion and report back. Also, read up on 'scope theory.
Does my comment "Most definitely a trigger level (jump) issue....." make any sense to you? Raymond
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Re: 2247A occasional horizontal jitter
I could be wrong, and very frequently I am. But it seems to me that the lowest common denominator would be power.? I would suspect that sweep circuit electronics are getting a zap occasionally by a failing component (cap maybe).? It does not seem like there is any common thread in the horizontal sweep and vert amp which leads me to believe a lower layer contributor.? ? Sorry, just my two cents worth of rambling. ?
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From: [email protected] < [email protected]> On Behalf Of Alex Sent: Monday, July 10, 2023 10:38 To: [email protected]Subject: Re: [TekScopes2] 2247A occasional horizontal jitter ? Thanks for your response Dave.
At the time I was looking at some audio frequencies between 30Hz to 16Khz, sine wave, AC input coupling.
The jitter seems to occur regardless of the sweep speed or input amplitude, and also with DC coupling.
Just tried with a 1MHz sine wave just to check with a much higher frequency, and it is still doing the same, and at the corresponding much higher sweep speed setting.
Both channel 1 and 2 do exactly the same, I split the signal into both channels so I could watch them simultaneously.
When displaying the waveform the horizontal jitter amounts to between about 1/3 to 1/2 a division, no matter what sweep speed is selected. The waveform just briefly lurches to the right, and then jumps back to its original position at non-constant intervals. A few times also noted that sometimes the waveform even briefly stays in the shifted position to the right for 1-2 seconds and then jumps back but that is more like the exception. Displayed input amplitude seems very constant.
Interestingly with a square wave input at the same frequency/amplitude does not seem to exhibit any horizontal jitter that the equivalent sine wave shows. Perhaps a triggering issue as you mentioned?
Yes fan is working normally. The 224x (and 2252) scopes contrary to some of the 22xx models, all have internal fans fitted next to the power supply board which is located towards the center of the scope.
No other abnormal symptoms so far.
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Re: 2247A occasional horizontal jitter
On Mon, Jul 10, 2023 at 04:37 PM, Alex wrote:
Interestingly with a square wave input at the same frequency/amplitude does not seem to exhibit any horizontal jitter that the equivalent sine wave shows. Perhaps a triggering issue as you mentioned?
Most definitely a trigger level (jump) issue. With a sine wave, the trigger level influences the phase angle where the trace starts, with a square wave, any trigger level between the peak levels causes triggering at the same phase angle. In normal trigger mode, triggering would be interrupted momentarily whenever the trigger level lies outside the peak-peak levels, causing (brightness) flickering in the image. Raymond
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Re: 2247A occasional horizontal jitter
Does it show the same behavior if you select "NORM" mode for trigger?
Ozan
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On Mon, Jul 10, 2023 at 07:49 AM, Alex wrote:
Just in case this might be additional useful information:
Ch1 input a square wave, ch2 a sine wave. Both at same frequency and amplitude.
No jitter shown while trigger source is set to Ch1 (square wave).
Jitter returns when trigger source is set to Ch2 (sine wave).
If I reverse inputs, Ch1 gets the sine wave, and ch2 gets the square wave, with trigger source set to ch1, jitter is shown. With trigger source on ch2 no jitter.
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Re: 2247A occasional horizontal jitter
Here is a 9 second mp4 video file (18Mb) filmed with my cellphone:
https://miwww.com/tmp/2247A_jitter.mp4
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Re: 2247A occasional horizontal jitter
Just in case this might be additional useful information:
Ch1 input a square wave, ch2 a sine wave. Both at same frequency and amplitude.
No jitter shown while trigger source is set to Ch1 (square wave).
Jitter returns when trigger source is set to Ch2 (sine wave).
If I reverse inputs, Ch1 gets the sine wave, and ch2 gets the square wave, with trigger source set to ch1, jitter is shown. With trigger source on ch2 no jitter.
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Re: 2247A occasional horizontal jitter
Thanks for your response Dave.
At the time I was looking at some audio frequencies between 30Hz to 16Khz, sine wave, AC input coupling.
The jitter seems to occur regardless of the sweep speed or input amplitude, and also with DC coupling.
Just tried with a 1MHz sine wave just to check with a much higher frequency, and it is still doing the same, and at the corresponding much higher sweep speed setting.
Both channel 1 and 2 do exactly the same, I split the signal into both channels so I could watch them simultaneously.
When displaying the waveform the horizontal jitter amounts to between about 1/3 to 1/2 a division, no matter what sweep speed is selected. The waveform just briefly lurches to the right, and then jumps back to its original position at non-constant intervals. A few times also noted that sometimes the waveform even briefly stays in the shifted position to the right for 1-2 seconds and then jumps back but that is more like the exception. Displayed input amplitude seems very constant.
Interestingly with a square wave input at the same frequency/amplitude does not seem to exhibit any horizontal jitter that the equivalent sine wave shows. Perhaps a triggering issue as you mentioned?
Yes fan is working normally. The 224x (and 2252) scopes contrary to some of the 22xx models, all have internal fans fitted next to the power supply board which is located towards the center of the scope.
No other abnormal symptoms so far.
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Good council Sam and thank you once again.?
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Good morning Mike and thank you very much for that article and list.? I have the manual in front of me and I am going to compare.? The parts listing sure saves a ton of research on Digikey and others.? Thanks again!
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Thanks very much Sam.? I swear I looked on Ebay and other places, I may have used wrong search terms.? Like "capacitor kit for Techtronics" or something.? In any event, thanks I will pick one up.?
Joe K8FC?
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I found this old quote on cap replacement that should be noted again:
From: "Ozan" <ozan_g@...>To: [email protected]Sent: Friday, March 26, 2021 11:37:29 AMSubject: Re: [TekScopes] Recapping Tektronix 2465You may already know but at least in some service manuals componentplacement diagram shows location of C1132 and C1115 swapped(wrong). This was the case for my 2467B, I assume it also appliesto 2465B. While desoldering take a note of the original value tomake sure. Ozan
Sam Reaves
ARS W3OHM
Owner / Moderator of: LeCroy Owners Group on Groups.io
Sencore Owners Group on Groups.io Sprint Layout Group on Groups.io?? Pulsonix EDA Group on Groups.io
LPKF Owners Group on Groups.io
Electronics and Mechanical Hardware Design Engineering Manager
Staff Scientist Andritz Rolls Global Research Center (RETIRED)
One more thing on the capacitor set. The seller requests pictures of your PCB assemblies before he will ship you an order to assure that you will have a complete set of the correct capacitors. This is due to the variance of build between different versions of the PCB's.
He charges a little more for the parts but does supply quality long life 105C rated parts. Considering the time and effort to sort this out the price seems?reasonable.
I do not have any personal experience with this seller but I have seen comments around the web where people have been quite satisfied.
Sam W3OHM
Sam Reaves
ARS W3OHM
Owner / Moderator of: LeCroy Owners Group on Groups.io
Sencore Owners Group on Groups.io Sprint Layout Group on Groups.io?? Pulsonix EDA Group on Groups.io
LPKF Owners Group on Groups.io
Electronics and Mechanical Hardware Design Engineering Manager
Staff Scientist Andritz Rolls Global Research Center (RETIRED)
K8FC,
I think this is the kit you are looking for. He has offered this kit of caps for years:
?
Attached are the details.
Sam W3OHM
Sam Reaves
ARS W3OHM
Owner / Moderator of: LeCroy Owners Group on Groups.io
Sencore Owners Group on Groups.io Sprint Layout Group on Groups.io?? Pulsonix EDA Group on Groups.io
LPKF Owners Group on Groups.io
Electronics and Mechanical Hardware Design Engineering Manager
Staff Scientist Andritz Rolls Global Research Center (RETIRED)
On Sun, Jul 9, 2023 at 8:09?PM dxradio33 < k8fc@...> wrote: I have two power supplies for the 2445b and they both need new caps.? I know a few years ago there were cap kits that included all the key caps to replace in the supply.? My particular issue is with the AC High voltage section as the trace takes about 10 min to finally appear.? I have done some due diligence on the web looking but to no avail.? This is a great scope and I really want to freshen it up.? Any leads to cap kits ?? Or even a list of critical caps that have been replaced in the past would help.? Thanks in advance.
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One more thing on the capacitor set. The seller requests pictures of your PCB assemblies before he will ship you an order to assure that you will have a complete set of the correct capacitors. This is due to the variance of build between different versions of the PCB's.
He charges a little more for the parts but does supply quality long life 105C rated parts. Considering the time and effort to sort this out the price seems?reasonable.
I do not have any personal experience with this seller but I have seen comments around the web where people have been quite satisfied.
Sam W3OHM
Sam Reaves
ARS W3OHM
Owner / Moderator of: LeCroy Owners Group on Groups.io
Sencore Owners Group on Groups.io Sprint Layout Group on Groups.io?? Pulsonix EDA Group on Groups.io
LPKF Owners Group on Groups.io
Electronics and Mechanical Hardware Design Engineering Manager
Staff Scientist Andritz Rolls Global Research Center (RETIRED)
K8FC,
I think this is the kit you are looking for. He has offered this kit of caps for years:
?
Attached are the details.
Sam W3OHM
Sam Reaves
ARS W3OHM
Owner / Moderator of: LeCroy Owners Group on Groups.io
Sencore Owners Group on Groups.io Sprint Layout Group on Groups.io?? Pulsonix EDA Group on Groups.io
LPKF Owners Group on Groups.io
Electronics and Mechanical Hardware Design Engineering Manager
Staff Scientist Andritz Rolls Global Research Center (RETIRED)
On Sun, Jul 9, 2023 at 8:09?PM dxradio33 < k8fc@...> wrote: I have two power supplies for the 2445b and they both need new caps.? I know a few years ago there were cap kits that included all the key caps to replace in the supply.? My particular issue is with the AC High voltage section as the trace takes about 10 min to finally appear.? I have done some due diligence on the web looking but to no avail.? This is a great scope and I really want to freshen it up.? Any leads to cap kits ?? Or even a list of critical caps that have been replaced in the past would help.? Thanks in advance.
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There is a kit on Ebay for $60. This web page listes the capacitors, but I would compare them to the manual:
On Sun, Jul 9, 2023 at 8:09?PM dxradio33 < k8fc@...> wrote: I have two power supplies for the 2445b and they both need new caps.? I know a few years ago there were cap kits that included all the key caps to replace in the supply.? My particular issue is with the AC High voltage section as the trace takes about 10 min to finally appear.? I have done some due diligence on the web looking but to no avail.? This is a great scope and I really want to freshen it up.? Any leads to cap kits ?? Or even a list of critical caps that have been replaced in the past would help.? Thanks in advance.
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dxradio33
Sam Reaves
Michael A. Terrell