Re: 502A - Anyone looking to part with one?
Thank you John! I'll definitely keep you in mind if I run across one and need help finding any parts to restore it.
For the record, it appears you have quite the collection! I'm also wondering what size electric panel you have after seeing pictures of several classic scopes all displaying traces at the same time! :-)
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Re: 502A - Anyone looking to part with one?
Sorry Jason I only have 3 at present. However if you do find one that needs parts I do have lots of those. I checked eBay and there doesn¡¯t look like there are any there at present. However once summer is over there should be a few show up. You can take a look at mine at:
Good luck on your quest.
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502A - Anyone looking to part with one?
Hello fellow scope addicts... that is to say... collectors!
Combing through the messages, it looks like I am about 8 years too late to the party for the batch of 502A scopes that were discovered in 2011. Regardless, it got me thinking if someone has a 502 or preferably a 502A in relatively good shape, that's one of the classics I wouldn't mind having for my audio frequency work. I figured I'd float it out here in case someone just happens to be cleaning out their ham shack, lab or is being "voluntold" to downsize their collection - I could provide one a good home. Hit me up if you qualify and maybe we can work something out.
Thanks and best regards,
Jason
|
Re: 11801C and the T1331 error: lost factory TB calibration data.
For some unexpected reason the formatting of my previous post was lost so here it is again in what I hope will be a more readable version:
Everyone:
The following subject threads with their email responses are "very" or "some what" relevant to this discussion of fixing lost cal data in the 11K series.
These are the TekScopes archive email numbers and the dates they were posted:
VERY RELEVANT
Programming a new NVRAM (Dallas DS1220Y) with a EPROM programmer
By Dennis Tillman W7PF ¡¤ #119113 ¡¤ 10/01/15
By Dennis Tillman W7PF ¡¤ #119111 ¡¤ 10/01/15
Repairing an expired NVRAM battery in 11A32, 11A33, 11A34, 11A72 plugins
By Vince Vielhaber ¡¤ #118126 ¡¤ 08/19/15
By Dennis Tillman W7PF ¡¤ #118121 ¡¤ 08/19/15
By Dennis Tillman W7PF ¡¤ #118115 ¡¤ 08/19/15
By Dennis Tillman W7PF ¡¤ #118063 ¡¤ 08/16/15
Addendum: Repairing an expired NVRAM battery in 11A32, 11A33, 11A34, 11A72 plugins
By Dennis Tillman W7PF ¡¤ #118098 ¡¤ 08/17/15
SOME-WHAT RELEVANT
11801 Sampling Head
By Dennis Tillman W7PF ¡¤ #119056 ¡¤ 09/29/15 ¡¤
By Dennis Tillman W7PF ¡¤ #119043 ¡¤ 09/28/15 ¡¤
Tektronix 11000 series vs. modern scopes. Sampling rate and aliasing questions.
By ditter2 ¡¤ #96382 ¡¤ 07/26/13
11A33 - what are possible problems, gotchas, and revisions?
By cheater cheater ¡¤ #96393 ¡¤ 07/27/13
By fjh001 ¡¤ #96406 ¡¤ 07/27/13
I hope this helps. Often, although it may not be the exact answer to your specific problem, it will guide you to a solution. If that is the case please share it with the forum so we can add it to our "bag of tricks".
Dennis Tillman W7PF
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Albert Otten Sent: Friday, August 23, 2019 9:22 AM To: [email protected]Subject: Re: [TekScopes] 11801C and the T1331 error: lost factory TB calibration data. [This topic continued from /g/TekScopes/message/158778 ] I know the discussion was about the later CSA803(A/B/C) and 11801(B/C). I have an 803 and an 803A. The U500/U511 batteries in my 803 were dead, so factory calibration constants would have been lost and I could freely experiment with the CCALCORRECTION command. To my surprise this command was unknown to the 803. This is also confirmed by the commands lists in U810/U910 EPROM images. The CSA803 Service Reference is now available at Tekwiki (thanks H?kan!). There is no reference at all in that manual to factory set calibration constants. The corresponding texts in the C version was obviously added later on. So I am convinced that in the CSA803 nothing is lost when an A5 time base board Dallas chip dies. [[BTW in the pdf manuals provided by Tek you won't find words in the added text with an ordinary search. Likely Tek used a custom character coding in the added text. If you copy-paste for instance T1331 from the added text into the search field then you will find the other instances of T1331 in the added text.] Albert On Thu, Aug 15, 2019 at 04:21 PM, freemail8877 wrote:
Hi, first post to this forum. I have very much enjoyed browsing, and
thought I could contribute with this information. Thanks guys for
keeping this forum so interesting. The T1331 (loss of battery backed
up information in the Time Base/Controller board NVRAMs) seems to be
an error to avoid, by backing up/replacing the NVRAMs on that board.
See e.g. the topic "Saving A5 Timing Board NVRAM calibration constants
CSA803 (A/C) and 11801(B/C)" for how to. To answer some question
raised there, here is some information from the Tektronix documentation.
In the 11801C User Manual (070-9971-01), on p. 3-112 (p.262/440 of
the pdf), I found this:
"Initializing and Erasing Nonvolatile RAM:
...
The following information is not lost:
...
- Factory calibration constants, which are established at the factory
and cannot be changed by the user or by the 11801C
- Enhanced Accuracy calibration constants, which are periodically
calculated and updated ..."
And in the 11801C Service Manual (070-9972-02) on p. 6-108 (p.244/286)
it is
stated:
"Time Base Calibration Errors:
...
Calibration data to enhance the time interpolator linearity is stored
in NVRAM on the Time Base/Controller board. If this NVRAM fails, a
T1331 error occurs during power-up diagnostics. The values are written
at the factory with the GPIB command CALCORRECTION.
CALCORRECTION<ui>:N
where <ui> = 0..32 and N = -128..+127
CAUTION: The calibration enhancement values are set at time of manufacture.
There is no query form of this command. Do NOT reset these values. If
a T1331 failure occurs during extended power-up diagnostics or you
suspect a time interpolator error, contact Tekronix factory service.
A T1331 failure causes all N values in the 33 ui locations to be reset
to zero. The oscilloscope will still run, but with decreased accuracy
in the time interpolator linearity. Resetting NVRAM with the Teksecure
feature does not affect the Time Base/Controller board NVRAM."
So now the big question seems to be:
Does anybody in the group know, or know who might know, how the
factory calibration procedure is, how the 33 N-values are determined?
Does anybody know how much the accuracy is affected?
Monica A.
PS:
I have for many years been a Tektronix scopes addict, It started with
the fascination in late 60's and early 70's, when I saw and used a 535
with Type CA plugin at my father's workplace. Being interested in
electronics, this was heaven. I now have a 7904a with sampling and
non-sampling plugins, a 7704a which rudely enough let the smoke out of
the power supply, a newly acquired 7603, and a 468. The design and
layout of the fronts are just so great. An 11801C is on the way in, so
I have used search a lot lately. It is said to pass POST, and a
picture shows the graticule on the screen, so hopefully it's OK.
-- Dennis Tillman W7PF TekScopes Moderator -- Dennis Tillman W7PF TekScopes Moderator
|
Re: 11801C and the T1331 error: lost factory TB calibration data.
Everyone:
The following subject threads with their email responses are "very" or "some what" relevant to this discussion of fixing lost cal data in the 11K series. These are the TekScopes archive email numbers and the dates they were posted:
VERY RELEVANT
Programming a new NVRAM (Dallas DS1220Y) with a EPROM programmer
By Dennis Tillman W7PF ¡¤ #119113 ¡¤ 10/01/15
By Dennis Tillman W7PF ¡¤ #119111 ¡¤ 10/01/15
Repairing an expired NVRAM batteryin11A32,11A33,11A34, 11A72 plugins
By Vince Vielhaber ¡¤ #118126 ¡¤ 08/19/15
By Dennis Tillman W7PF ¡¤ #118121 ¡¤ 08/19/15
By Dennis Tillman W7PF ¡¤ #118115 ¡¤ 08/19/15
By Dennis Tillman W7PF ¡¤ #118063 ¡¤ 08/16/15
Addendum: Repairing an expired NVRAM battery in 11A32, 11A33, 11A34, 11A72 plugins
By Dennis Tillman W7PF ¡¤ #118098 ¡¤ 08/17/15
11801 Sampling Head
By Dennis Tillman W7PF ¡¤ #119056 ¡¤ 09/29/15 ¡¤
By Dennis Tillman W7PF ¡¤ #119043 ¡¤ 09/28/15 ¡¤
SOME-WHAT RELEVANT
Tektronix 11000 series vs. modern scopes. Sampling rate and aliasing questions.
By ditter2 ¡¤ #96382 ¡¤ 07/26/13
11A33 - what are possible problems, gotchas, and revisions?
By cheater cheater ¡¤ #96393 ¡¤ 07/27/13
By fjh001 ¡¤ #96406 ¡¤ 07/27/13
I hope this helps. Often, although it may not be the exact answer to your specific problem, it will guide you to a solution. If that is the case please share it with the forum so we can add it to our "bag of tricks".
Dennis Tillman W7PF
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Albert Otten Sent: Friday, August 23, 2019 9:22 AM To: [email protected]Subject: Re: [TekScopes] 11801C and the T1331 error: lost factory TB calibration data. [This topic continued from /g/TekScopes/message/158778 ] I know the discussion was about the later CSA803(A/B/C) and 11801(B/C). I have an 803 and an 803A. The U500/U511 batteries in my 803 were dead, so factory calibration constants would have been lost and I could freely experiment with the CCALCORRECTION command. To my surprise this command was unknown to the 803. This is also confirmed by the commands lists in U810/U910 EPROM images. The CSA803 Service Reference is now available at Tekwiki (thanks H?kan!). There is no reference at all in that manual to factory set calibration constants. The corresponding texts in the C version was obviously added later on. So I am convinced that in the CSA803 nothing is lost when an A5 time base board Dallas chip dies. [[BTW in the pdf manuals provided by Tek you won't find words in the added text with an ordinary search. Likely Tek used a custom character coding in the added text. If you copy-paste for instance T1331 from the added text into the search field then you will find the other instances of T1331 in the added text.] Albert On Thu, Aug 15, 2019 at 04:21 PM, freemail8877 wrote:
Hi, first post to this forum. I have very much enjoyed browsing, and
thought I could contribute with this information. Thanks guys for
keeping this forum so interesting. The T1331 (loss of battery backed
up information in the Time Base/Controller board NVRAMs) seems to be
an error to avoid, by backing up/replacing the NVRAMs on that board.
See e.g. the topic "Saving A5 Timing Board NVRAM calibration constants
CSA803 (A/C) and 11801(B/C)" for how to. To answer some question
raised there, here is some information from the Tektronix documentation.
In the 11801C User Manual (070-9971-01), on p. 3-112 (p.262/440 of
the pdf), I found this:
"Initializing and Erasing Nonvolatile RAM:
...
The following information is not lost:
...
- Factory calibration constants, which are established at the factory
and cannot be changed by the user or by the 11801C
- Enhanced Accuracy calibration constants, which are periodically
calculated and updated ..."
And in the 11801C Service Manual (070-9972-02) on p. 6-108 (p.244/286)
it is
stated:
"Time Base Calibration Errors:
...
Calibration data to enhance the time interpolator linearity is stored
in NVRAM on the Time Base/Controller board. If this NVRAM fails, a
T1331 error occurs during power-up diagnostics. The values are written
at the factory with the GPIB command CALCORRECTION.
CALCORRECTION<ui>:N
where <ui> = 0..32 and N = -128..+127
CAUTION: The calibration enhancement values are set at time of manufacture.
There is no query form of this command. Do NOT reset these values. If
a T1331 failure occurs during extended power-up diagnostics or you
suspect a time interpolator error, contact Tekronix factory service.
A T1331 failure causes all N values in the 33 ui locations to be reset
to zero. The oscilloscope will still run, but with decreased accuracy
in the time interpolator linearity. Resetting NVRAM with the Teksecure
feature does not affect the Time Base/Controller board NVRAM."
So now the big question seems to be:
Does anybody in the group know, or know who might know, how the
factory calibration procedure is, how the 33 N-values are determined?
Does anybody know how much the accuracy is affected?
Monica A.
PS:
I have for many years been a Tektronix scopes addict, It started with
the fascination in late 60's and early 70's, when I saw and used a 535
with Type CA plugin at my father's workplace. Being interested in
electronics, this was heaven. I now have a 7904a with sampling and
non-sampling plugins, a 7704a which rudely enough let the smoke out of
the power supply, a newly acquired 7603, and a 468. The design and
layout of the fronts are just so great. An 11801C is on the way in, so
I have used search a lot lately. It is said to pass POST, and a
picture shows the graticule on the screen, so hopefully it's OK.
-- Dennis Tillman W7PF TekScopes Moderator
|
Re: Looking for Tek 2712 spectrum analyzer parts.
On 8/22/19 5:51 PM, Randy.AB9GO wrote: I know this may be a long shot but I am looking for an N connector and coax
assembly for a 2712. Also if someone has a good condition plastic end
panel for the back and the feet I'm looking for that also. Most important
thing is definitely the n connector. One side of the center pin is
missing. before I go to the trouble of a recalibration I would like to
have a good female N connector. An even longer shot would be the stuff for the internal Tracking Generator option. Failing that, the plumbing to get the LO to the rear connector for the external Tracking Generator option is another roadblock, almost as large as auction-site prices for the Tek 2707.? FWIW, the 2707 has an N connector.... -- Jeff Woolsey {{woolsey,jlw}@jlw,first.last@{gmail,jlw}}.com Nature abhors straight antennas, clean lenses, and empty storage. "Delete! Delete! OK!" -Dr. Bronner on disk space management Card-sorting, Joel. -Crow on solitaire
|
Re: Tek 576 Curve Tracer HV Transformer winding
|
Re: 11801C and the T1331 error: lost factory TB calibration data.
[This topic continued from /g/TekScopes/message/158778 ] I know the discussion was about the later CSA803(A/B/C) and 11801(B/C). I have an 803 and an 803A. The U500/U511 batteries in my 803 were dead, so factory calibration constants would have been lost and I could freely experiment with the CCALCORRECTION command. To my surprise this command was unknown to the 803. This is also confirmed by the commands lists in U810/U910 EPROM images. The CSA803 Service Reference is now available at Tekwiki (thanks H?kan!). There is no reference at all in that manual to factory set calibration constants. The corresponding texts in the C version was obviously added later on. So I am convinced that in the CSA803 nothing is lost when an A5 time base board Dallas chip dies. [[BTW in the pdf manuals provided by Tek you won't find words in the added text with an ordinary search. Likely Tek used a custom character coding in the added text. If you copy-paste for instance T1331 from the added text into the search field then you will find the other instances of T1331 in the added text.] Albert
On Thu, Aug 15, 2019 at 04:21 PM, freemail8877 wrote:
Hi, first post to this forum. I have very much enjoyed browsing, and thought I
could contribute with this information. Thanks guys for keeping this forum so
interesting. The T1331 (loss of battery backed up information in the Time
Base/Controller board NVRAMs) seems to be an error to avoid, by backing
up/replacing the NVRAMs on that board. See e.g. the topic "Saving A5 Timing
Board NVRAM calibration constants CSA803 (A/C) and 11801(B/C)" for how to. To
answer some question raised there, here is some information from the Tektronix
documentation.
In the 11801C User Manual (070-9971-01), on p. 3-112 (p.262/440 of the pdf),
I found this:
"Initializing and Erasing Nonvolatile RAM:
...
The following information is not lost:
...
- Factory calibration constants, which are established at the factory and
cannot be changed by the user or by the 11801C
- Enhanced Accuracy calibration constants, which are periodically calculated
and updated
..."
And in the 11801C Service Manual (070-9972-02) on p. 6-108 (p.244/286) it is
stated:
"Time Base Calibration Errors:
...
Calibration data to enhance the time interpolator linearity is stored in NVRAM
on the Time Base/Controller board. If this NVRAM fails, a T1331 error occurs
during power-up diagnostics. The values are written at the factory with the
GPIB command CALCORRECTION.
CALCORRECTION<ui>:N
where <ui> = 0..32 and N = -128..+127
CAUTION: The calibration enhancement values are set at time of manufacture.
There is no query form of this command. Do NOT reset these values. If a T1331
failure occurs during extended power-up diagnostics or you suspect a time
interpolator error, contact Tekronix factory service.
A T1331 failure causes all N values in the 33 ui locations to be reset to
zero. The oscilloscope will still run, but with decreased accuracy in the time
interpolator linearity. Resetting NVRAM with the Teksecure feature does not
affect the Time Base/Controller board NVRAM."
So now the big question seems to be:
Does anybody in the group know, or know who might know, how the factory
calibration procedure is, how the 33 N-values are determined?
Does anybody know how much the accuracy is affected?
Monica A.
PS:
I have for many years been a Tektronix scopes addict, It started with the
fascination in late 60's and early 70's, when I saw and used a 535 with Type
CA plugin at my father's workplace. Being interested in electronics, this was
heaven. I now have a 7904a with sampling and non-sampling plugins, a 7704a
which rudely enough let the smoke out of the power supply, a newly acquired
7603, and a 468. The design and layout of the fronts are just so great. An
11801C is on the way in, so I have used search a lot lately. It is said to
pass POST, and a picture shows the graticule on the screen, so hopefully it's
OK.
|
Jon,
You might try emailing Forrest Burton (forrestburton@...). He produces replacements (3D printed) that seem pretty good quality.? I have a set of his replacements on my old Tek 454 that work very well.
I have no affiliation with him or his small side business.? I just happen to know of him...? :)
Hope this helps.Regards,Vern
toggle quoted message
Show quoted text
On Friday, August 23, 2019, 1:48:23 AM PDT, Jean-Paul <jonpaul@...> wrote:
Hello all: restoring a 2465B TEK scope that is missing the front and rear feet:
2 pcs foot bottom front plastic 348-0740-00
2 pcs foot cabinet cord wrap 348-0729-01
Also missing the? special TORX - 15 screws.
I looked on the Qservice website but these seem out of stock.
If anyone has some or is parting out a junker unit, I will appreciate!
MANY THANKS!
Jon
|
I'll see what I can get for you.
toggle quoted message
Show quoted text
On Fri, Aug 23, 2019 at 3:48 AM Jean-Paul <jonpaul@...> wrote: Hello all: restoring a 2465B TEK scope that is missing the front and rear
feet:
2 pcs foot bottom front plastic 348-0740-00
2 pcs foot cabinet cord wrap 348-0729-01
Also missing the special TORX - 15 screws.
I looked on the Qservice website but these seem out of stock.
If anyone has some or is parting out a junker unit, I will appreciate!
MANY THANKS!
Jon
|
Re: Tek 576 Curve Tracer HV Transformer winding
This thread in TekScopes may help. It includes the participants and the
message numbers.
SUBJECT: Restoration of a 576 Curve Tracer (High Voltage Xfmr)
ulf_r_k 09/18/16 #131067
ykochcal 09/18/16 #131068
Dave Wise 09/18/16 #131069
drawding@... 09/19/16 #131081
ulf_r_k 09/19/16 #131083
ykochcal 09/19/16 #131085
ykochcal 09/26/16 #131247
Dennis Tillman W7PF
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of David C. Partridge Sent: Friday, August 23, 2019 4:56 AM To: [email protected]Subject: Re: [TekScopes] Tek 576 Curve Tracer HV Transformer winding David Rawding *used* to supply replacements for the 576 transformer, who I believe was once (and may still be) a member of the group? HtH David -----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Miguel Work Sent: 23 August 2019 12:26 To: [email protected]Subject: Re: [TekScopes] Tek 576 Curve Tracer HV Transformer winding 8070008 -----Mensaje original----- De: [email protected] [mailto: [email protected]] En nombre de Craig Sawyers Enviado el: viernes, 23 de agosto de 2019 9:13 Para: [email protected]Asunto: Re: [TekScopes] Tek 576 Curve Tracer HV Transformer winding Tektronix 567 EHT rewinding pictures from Craig
Tektronix 567 EHT rewinding pictures from Craig Thanks for remembering where the pics were stored! I used a pot core former, which was too high. So I cut a cheek off, shortened the tube and stuck the cheek back on (superglue). I used a cheap manual winding machine from eBay, and used Ulf's wind and retrace method to limit voltage from layer to layer. Once finished I wax potted in an a mix of beeswax and candle wax (percentage - can't remember. Googled it), until bubbles stopped coming out, then gave it maybe another half hour to soak. Then let it drip. It has worked perfectly ever since. The 576 was free, so time and not much money to get it working again was a bonus. The multiple tags on the bobbin were a boon - because the 0.1mm wire breaks a few times during winding, you just terminate it on a pin and continue winding. Craig -- Dennis Tillman W7PF TekScopes Moderator
|
Re: Tek 576 Curve Tracer HV Transformer winding
David Rawding *used* to supply replacements for the 576 transformer, who I
believe was once (and may still be) a member of the group?
HtH
David
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Miguel Work Sent: 23 August 2019 12:26 To: [email protected]Subject: Re: [TekScopes] Tek 576 Curve Tracer HV Transformer winding 8070008 -----Mensaje original----- De: [email protected] [mailto: [email protected]] En nombre de Craig Sawyers Enviado el: viernes, 23 de agosto de 2019 9:13 Para: [email protected]Asunto: Re: [TekScopes] Tek 576 Curve Tracer HV Transformer winding Tektronix 567 EHT rewinding pictures from Craig
Tektronix 567 EHT rewinding pictures from Craig Thanks for remembering where the pics were stored! I used a pot core former, which was too high. So I cut a cheek off, shortened the tube and stuck the cheek back on (superglue). I used a cheap manual winding machine from eBay, and used Ulf's wind and retrace method to limit voltage from layer to layer. Once finished I wax potted in an a mix of beeswax and candle wax (percentage - can't remember. Googled it), until bubbles stopped coming out, then gave it maybe another half hour to soak. Then let it drip. It has worked perfectly ever since. The 576 was free, so time and not much money to get it working again was a bonus. The multiple tags on the bobbin were a boon - because the 0.1mm wire breaks a few times during winding, you just terminate it on a pin and continue winding. Craig
|
Re: Tek 576 Curve Tracer HV Transformer winding
Well found. Yes - I got mine from Mark Hennesy. It was in a cupboard at the BBC research department where he worked, and he saved it from getting thrown out into a skip. Craig From: [email protected] [mailto:[email protected]] On Behalf Of Miguel Work
Sent: 23 August 2019 12:26
To: [email protected]
Subject: Re: [TekScopes] Tek 576 Curve Tracer HV Transformer winding
-----Mensaje original-----
De: [email protected] [mailto:[email protected]] En nombre de Craig Sawyers Enviado el:
viernes, 23 de agosto de 2019 9:13
Para: [email protected]
Asunto: Re: [TekScopes] Tek 576 Curve Tracer HV Transformer winding
Tektronix 567 EHT rewinding pictures from Craig
Tektronix 567 EHT rewinding pictures from Craig Thanks for remembering where the pics were stored! I used a pot core former, which was too high. So I cut a cheek off, shortened the tube and stuck the cheek back on (superglue). I used a cheap manual winding machine from eBay, and used Ulf's wind and retrace method to limit voltage from layer to
layer. Once finished I wax potted in an a mix of beeswax and candle wax (percentage - can't
remember.
Googled it), until bubbles stopped coming out, then gave it maybe another half hour to soak. Then let it drip.
It has worked perfectly ever since. The 576 was free, so time and not much money to get it working
again was a bonus.
The multiple tags on the bobbin were a boon - because the 0.1mm wire breaks a few times during
winding, you just terminate it on a pin and continue winding.
Craig
|
Re: Tek 576 Curve Tracer HV Transformer winding
-----Mensaje original----- De: [email protected] [mailto: [email protected]] En nombre de Craig Sawyers Enviado el: viernes, 23 de agosto de 2019 9:13 Para: [email protected]Asunto: Re: [TekScopes] Tek 576 Curve Tracer HV Transformer winding Tektronix 567 EHT rewinding pictures from Craig
Tektronix 567 EHT rewinding pictures from Craig Thanks for remembering where the pics were stored! I used a pot core former, which was too high. So I cut a cheek off, shortened the tube and stuck the cheek back on (superglue). I used a cheap manual winding machine from eBay, and used Ulf's wind and retrace method to limit voltage from layer to layer. Once finished I wax potted in an a mix of beeswax and candle wax (percentage - can't remember. Googled it), until bubbles stopped coming out, then gave it maybe another half hour to soak. Then let it drip. It has worked perfectly ever since. The 576 was free, so time and not much money to get it working again was a bonus. The multiple tags on the bobbin were a boon - because the 0.1mm wire breaks a few times during winding, you just terminate it on a pin and continue winding. Craig
|
Re: 7104 odd beam fault - whole screen illuminated
Nothing like as extreme as yours, but I had a 485 with a diffuse glow over about a quarter of the screen area on the right side. It varied with intensity control but not anything else until I noticed a very slight jump when the timebase was retracing on its slowest sweep speed. Dead output transistor in the X amplifier, I assume the beam was deflected so far that it was reflecting off the X deflection plate and spraying around ( or maybe secondary emission from the X plate?). I hope your 7104 problem is no worse than that, maybe one of the CRT electrodes is completely disconnected?
Roger
|
The problem is that connecting up the voltage to the input capacitor will put a DC voltage transient
up the innards of the AA501 while the cap charges up. That is the reason the 7A19 and 7A29 plugs in
have a "pre-charge" position of the input selector.
Craig
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Show quoted text
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of EJP
Sent: 23 August 2019 09:06
To: [email protected]
Subject: Re: [TekScopes] AA501 DC offset
I misread the parts list. The AA501 input caps are C1630/1, 1uF 5% 400V metallized film.
The answer to my question turns out to be that the AA501 will survive it, but the Device Under Test
may not ;-)
EJP
|
Hello all: restoring a 2465B TEK scope that is missing the front and rear feet:
2 pcs foot bottom front plastic 348-0740-00
2 pcs foot cabinet cord wrap 348-0729-01
Also missing the special TORX - 15 screws.
I looked on the Qservice website but these seem out of stock.
If anyone has some or is parting out a junker unit, I will appreciate!
MANY THANKS!
Jon
|
I misread the parts list. The AA501 input caps are C1630/1, 1uF 5% 400V metallized film.
The answer to my question turns out to be that the AA501 will survive it, but the Device Under Test may not ;-)
EJP
|
Re: Tek 576 Curve Tracer HV Transformer winding
Tektronix 567 EHT rewinding pictures from Craig
Tektronix 567 EHT rewinding pictures from Craig Thanks for remembering where the pics were stored! I used a pot core former, which was too high. So I cut a cheek off, shortened the tube and stuck the cheek back on (superglue). I used a cheap manual winding machine from eBay, and used Ulf's wind and retrace method to limit voltage from layer to layer. Once finished I wax potted in an a mix of beeswax and candle wax (percentage - can't remember. Googled it), until bubbles stopped coming out, then gave it maybe another half hour to soak. Then let it drip. It has worked perfectly ever since. The 576 was free, so time and not much money to get it working again was a bonus. The multiple tags on the bobbin were a boon - because the 0.1mm wire breaks a few times during winding, you just terminate it on a pin and continue winding. Craig
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How big is the original input cap? If it's reasonably small, you can put a much larger - say ten to a hundred times bigger - external plastic cap in series, with suitable voltage rating. A bipolar Zener clamp (like 10-27 Vz) behind it can shunt the charging currents upon hookup or power-up/down, to protect the input.
Ed
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Jason A.
John Williams
David C. Partridge
Jean-Paul