Re: Problems with 465 - Looking for Help!
Thanks Harvey!
I have a digital scope and will check the power supply ripple with it, post what I find.?
Sent using the mobile mail app
On 9/9/22 at 11:11 PM, Harvey White wrote:
From: "Harvey White" <madyn@...> Date: September 9, 2022 To: [email protected]Cc: Subject: Re: [TekScopes2] Problems with 465 - Looking for Help!
You'll find that, like everything else, you'll want another scope
to help repair this one.? Not absolutely needed, but it makes a
difference.?
Harvey
On 9/9/2022 11:45 PM, Ed Riley wrote:
toggle quoted message
Show quoted text
Thanks Harvey and
Michael!
Exactly the?kind of
guidance I was looking for!
It’s my first scope
repair but looks to be a great learning project.?
Sent using the mobile mail app
On 9/9/22 at 6:32 PM, Harvey White wrote:
From: "Harvey White" <madyn@...>
Date: September 9, 2022
To: [email protected]
Cc:
Subject: Re: [TekScopes2] Problems with 465 - Looking for
Help! What happens with out of tolerance power supply voltages
varies according to the circuit, things that ought to adjust
properly won't.? Ripple on a power supply can creep
anywhere, and generally does.? It presents itself as an
unwanted signal that is gleefully seized by properly
operating circuitry and treated as something valid.
Harvey
On 9/9/2022 6:28 PM, Michael
wrote:
Your LV supply will cause this issue. ?I just repaired a 465
that had almost identical issues. ?Your reported ?LV
voltages are not ideal, I would bet that there is excess
ripple on one or more of the LV rails. ?
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Re: Problems with 465 - Looking for Help!
You'll find that, like everything else, you'll want another scope
to help repair this one.? Not absolutely needed, but it makes a
difference.?
Harvey
On 9/9/2022 11:45 PM, Ed Riley wrote:
toggle quoted message
Show quoted text
Thanks Harvey and
Michael!
Exactly the?kind of
guidance I was looking for!
It’s my first scope
repair but looks to be a great learning project.?
Sent using the mobile mail app
On 9/9/22 at 6:32 PM, Harvey White wrote:
From: "Harvey White" <madyn@...>
Date: September 9, 2022
To: [email protected]
Cc:
Subject: Re: [TekScopes2] Problems with 465 - Looking for
Help! What happens with out of tolerance power supply voltages
varies according to the circuit, things that ought to adjust
properly won't.? Ripple on a power supply can creep
anywhere, and generally does.? It presents itself as an
unwanted signal that is gleefully seized by properly
operating circuitry and treated as something valid.
Harvey
On 9/9/2022 6:28 PM, Michael
wrote:
Your LV supply will cause this issue. ?I just repaired a 465
that had almost identical issues. ?Your reported ?LV
voltages are not ideal, I would bet that there is excess
ripple on one or more of the LV rails. ?
|
Re: Problems with 465 - Looking for Help!
Thanks Harvey and Michael!
Exactly the?kind of guidance I was looking for!
It’s my first scope repair but looks to be a great learning project.?
Sent using the mobile mail app
On 9/9/22 at 6:32 PM, Harvey White wrote:
From: "Harvey White" <madyn@...> Date: September 9, 2022 To: [email protected]Cc: Subject: Re: [TekScopes2] Problems with 465 - Looking for Help!
What happens with out of tolerance power supply voltages varies
according to the circuit, things that ought to adjust properly
won't.? Ripple on a power supply can creep anywhere, and generally
does.? It presents itself as an unwanted signal that is gleefully
seized by properly operating circuitry and treated as something
valid.
Harvey
On 9/9/2022 6:28 PM, Michael wrote:
toggle quoted message
Show quoted text
Your LV supply will cause this issue. ?I just repaired a 465 that
had almost identical issues. ?Your reported ?LV voltages are not
ideal, I would bet that there is excess ripple on one or more of
the LV rails. ?
|
Re: Problems with 465 - Looking for Help!
What happens with out of tolerance power supply voltages varies
according to the circuit, things that ought to adjust properly
won't.? Ripple on a power supply can creep anywhere, and generally
does.? It presents itself as an unwanted signal that is gleefully
seized by properly operating circuitry and treated as something
valid.
Harvey
On 9/9/2022 6:28 PM, Michael wrote:
toggle quoted message
Show quoted text
Your LV supply will cause this issue. ?I just repaired a 465 that
had almost identical issues. ?Your reported ?LV voltages are not
ideal, I would bet that there is excess ripple on one or more of
the LV rails. ?
|
Re: Problems with 465 - Looking for Help!
Your LV supply will cause this issue. ?I just repaired a 465 that had almost identical issues. ?Your reported ?LV voltages are not ideal, I would bet that there is excess ripple on one or more of the LV rails. ?
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Problems with 465 - Looking for Help!
New member here. I posted this incorrectly my first time since I put the comments with the pictures. My screenshot pictures are at this link: /g/TekScopes2/album?id=278262I'm looking for help with my first scope repair. My 465 recently failed. Worked fine one day and not so much the next. With no input signal I no longer have a clean trace but rather some type of spurious image is present as shown in the No Signal Screreen picture. Using the position controls I can adjust that signal "ghost image" horizontally but not vertically. The 9KHz signal originates near the center of the screen, expands and then rebounds from the left side of the screen, eventually compressing and exiting on the right side of the screen. There is also a blip trace out to the right of the 9KHz signal that does not vary with the input frequency or amplitude. The 9KHz signal can be adjusted horizontally but not vertically.? All symptoms are identical on the A and B channels. I've tested the power supply low voltages as: Design Actual 110 104.5 5 4.99 55 54.91 22 17.89 15 12.92 -8 -7.95 I'm currently troubleshooting the low voltage power supply but I don't think the spurious image would necessarily originate there. Does the fact I can adjust the spurious image as well as the 9KHz signal horizontally but not vertically indicate a problem in the vertical amplifier section? Any guidance will be appreciated!?
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Interesting. So one question I had on these is - they're not supposed to be rechargeable, correct?
Digikey has what may be the same battery, but with leads:?.
I'm not sure if anyone has some tips on fitting a regular battery with no leads (I'd probably just go to the uber-retailer with next or even same day delivery here in the US in that case). But from my current vantage point having leads is essential for the fit of a given battery in this scope. Something very simple and/or practical I'm missing??
Thank you, Radu.?
TDS 460 repair
Digi-Key BR-2/3AT2SPN
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TDS 460 repair
Digi-Key BR-2/3AT2SPN
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Going back to the 6-49 troubleshooting flow, I still don't have a clear identification for P2 (this thread -? /g/TekScopes/topic/tds460a_will_not_turn_on/32887222?p=Created%2C%2C%2C20%2C1%2C0%2C0&prev=1?- says it's the "22 pin connector," which I don't think is correct), but I disconnected what I think is the REM PWR (p.9-2), to no avail. Dead scope almost entirely, except the most faint fan movement at time or turning on the main rear switch.? So I'm beginning to think the issue resides entirely on A25, the "LV PS." I am not sure if anyone has tested this out of the scope (connect isolated 120V directly into it)? Loads needed on output? Some sort of crank (bootstrapping) to start it?? Thank you, Radu.?
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Hi Graham.
Hope all are well.
So long as you can adjust the probes compensation to match the 'scope input (so you get that nice flat top square wave with no overshoot etc) you should be good to go, with minimal degradation of the overall bandwidth.
ISTR, there is something in the manual of the 475 (and probably the probe) that gives a formula or nomograph, indicating any bandwidth reduction caused by a lower bandwidth probe.
Back in the day, we used to check such things with a fast rise pulse gen, take the indicated system rise time (without and with probe) and calculate the bandwidth based on that.? Again, an example calculation between rise-time and bandwidth is I think in the user manual.
It may (or may not) flip the X1 / X10 indicator on the 'scope though.? If it has the small pin sticking out of the BNC plug, it should, if not, it wont.
Cheers.
??? Dave B.
--
Created on and sent from a Unix like PC running and using free and open source software:
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Hi All,
Anyone know of any issue using a P5050 (500MHz) 10X probe on a
sub-200MHz scope (475, 7603) or others.
--
Best regards,
Graham
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Continuing in the troubleshooting work, I figured one of the internal batteries is low (the bottom one, and it always seems to be that one). It seems replacing it only results in loss of custom settings (adjustment/calibration constants are in non-volatile memory).
Does anyone have good information on replacement batteries (model, type, etc.) from a good source?
Thankyou,
Radu.?
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File /TDS 460A Documentation/070-9219-00.pdf uploaded
#file-notice
The following files and folders have been uploaded to
the Files area of the [email protected] group.
By: Radu Bogdan Dicher <vondicher@...>
Description:
Reportedly, this scope has a similar PS configuration with the TDS460A.
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(I'm not sure whether the moderators can change the name of a thread, but may be worth doing that if possible for clarity)
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There's an error in the name of this thread - the scope I have is a TDS 460A. I'm not sure exactly how critical this suffix is, but hopefully I didn't create too much inconvenience to anyone looking into this and trying to help.
Thank you,
Radu.?
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Radu Bogdan Dicher <vondicher@...> added folder /TDS 460 Documentation
The following files and folders have been uploaded to
the Files area of the [email protected] group.
By: Radu Bogdan Dicher <vondicher@...>
Description:
Service Manual
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- Primary Troubleshooting procedure has a step where all cables should be checked and reseated if necessary. J7 on the backplane, which was a bit off (a little out on one side) I feel had a bit of effect in that the fan now moves a bit now when the rear power switch?is turned on. The unit has to have been off for a bit for this movement to occur.?
- The above took me to the LV PS Troubleshooting procedure, which, puzzlingly, if no "secondary voltages" on J2, directs the issue on the backplane. I do not understand this, as no output from the PS board would mean to me there are issues on it, not somewhere else. But of course, also, a short somewhere else may suppress?any output. But on all rails??
- Nevermind, I hopped on the?Backplane Troubleshooting?next, as directed by the troubleshooting workflow. On its Figure 6-49, I am asked to disconnect P2 (which is something between A07 and A25). Can anyone shed some light on what this "P2" is? I have not been able to identify it in the manual, if my life depended on it. But maybe someone having worked on this before may know.
Thank you, Radu.?
I have two of these, the power supplies are very problematic.? I have replaced the PS on both of my TDS460A models.? I was even able to repair one supply and bring it back to life by replacing some regulators on the boards. ?
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I have two of these, the power supplies are very problematic. ?I have replaced the PS on both of my TDS460A models. ?I was even able to repair one supply and bring it back to life by replacing some regulators on the boards. ?
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Michael