Date   

465 scope component question

Bill
 

On the A9 Interface Circuit Board I ran into a problem identifying a component. On page 198 of the service manual for scopes 250,000 and up at Position E3 near Q1474 note C1474, R1473, R1472 and CR1472. In my scope there is a very small ceramic capacitor in front of what appears to be a large ceramic capacitor, could be C1474?? There are not two of them shown in the diagram in the manual. The larger component has markings on it, CE .1k 200 volt, and is the component I'm not sure of. Any ideas?
Thanks,
Bill


Re: Corrosion Damage – TM500 Plugins

Jim Adney
 

On Sat, Apr 24, 2021 at 02:58 AM, <christopherbath@hotmail.com> wrote:

I am not a chemist, and my knowledge of chemistry is limited however the
damage represents to me what I suspect is from a gaseous corrosive chemical
presumably that may have formed from either the foam or glue possibly under
summer conditions
I'm not a chemist either, but the answer may be simpler that you suspect. Your box is not hermetically sealed, so air will leak in and out of it with changes in barometric pressure. Thus, over time, this box "breathes". There's also a daily rise and fall in ambient temperature. As a result, there will be times when humid air is carried into the box just before the temperature drops below the dew point. This results in dew forming on anything in the box. It's just water, but it has condensed out of the air and has condensed on anything that is exposed to the air in the box, which means anything that isn't hermetically sealed.

This happens in cars, where rust appears to come out of places that have not been exposed to weather. These are sometimes referred to as "trapped volumes." It is common for trapped volumes in cars to have to paint or any other rust prevention coating, so they rust silently until the rust bubbles appear. This same problem happens in the gas tanks of stored cars: Dew typically forms inside the top of the tank, drips into any gas that's still in there, and eventually falls to the bottom, where it rusts the bottom of the tank.

So it's certainly possible that there's something special going on in your box, but it's also possible that this simpler explanation is all you need.


Re: Cure tracer with digital scope

Michael Dunn
 

Experimenting with displaying an "analog clock" on a digital scope:
https://www.edn.com/struggling-with-x-y-mode-or-what-time-is-it/


Re: Corrosion Damage – TM500 Plugins

christopherbath@...
 

Hi,

Sorry for the very long delay in replying. Inside the container is a black open cell foam with comparatively large cells. The foam had not broken down. It does appear the foam was glued in place and it is possible that the glue may have caused the issue. The outside of the box is made from plastic (possibly polyethylene). The case is almost airtight however would still allow any external humidity into the storage container. On top of the box was some other plugins with only a sheet of bubble wrap left on top of them which are totally unaffected, so it is very likely that something inside the box had caused the issue. The box from what I can tell is not that old and the plug-ins had probably been in the box for about 5 years.

The damage is strange. I am not a chemist, and my knowledge of chemistry is limited however the damage represents to me what I suspect is from a gaseous corrosive chemical presumably that may have formed from either the foam or glue possibly under summer conditions when the ambient temperature may have exceeded 40 degrees Celsius (104 degrees Fahrenheit).

The damage included the following:

• Corrosion to steel components such as screws and the coating (possibly zinc or similar)
• Oxidisation to aluminium including some small pitting in some areas.
• Damage (reaction) to copper and brass from penetration through plating such as nickel plated brass. Some tracks with silk screened coatings on
top showed some very minor damage. Gold plated components feared much better with almost no damage.
• Penetration inside some magnetically latching relays where the chemical appears to have penetrated the epoxy potting causing corrosion to some
of the mechanical parts.
• Accelerated damage where dissimilar metals had been in contact such as the screws with the aluminium frame.
• Inside the one of the plugins there is a plated steel or iron component that has had some of the plating come off. Obviously the chemical had
penetrated the plating (which would be to some extent porous anyway.
• Some “worming” to one aluminium front panel underneath the anodized finish.

The modules were no better off being fully wrapped in bubble wrap inside the container. The chemical also seems to have formed on the outside to the plastic components however after cleaning with ethanol the plastic does not appear to have been affected.

Any idea on what the chemical is that may have formed?

Thanks,

Chris


Re: Cure tracer with digital scope

santa0123456
 

Looks like I misunderstood X-Y use that is quite common with X/Y which is less used in the digital scopes world.

But this will only go further proving that you can do funny things in the digital world. After exporting your characteristics measured in X/Y mode for a lot of parts, you could make a table in excel of X-Y and even their root-mean-square to compare your bunch of parts and see which ones are best paired...


Re: 485 service manual is causing brain oscillations

satbeginner
 

Ok,

If the trimpot does not work, check the resistors around the trimpot and
the trimpot itself.


The way I understood the text in step 13 is:

If no improvement in the voltage can be reached by this procedure, set it
back to the voltage found earlier, and continue with step 14.

Again, I would check the components around the trimpot first.

Good luck,

Leo



On Sat, 24 Apr 2021, 06:26 Ondrej Pavelka, <info@vintageaudiorepairs.eu>
wrote:

Yeah yours is fixed, I still think I have a problem there because it says
to reset it back to noted voltage but in my case the trimpot setting has no
impact on the voltage value.

Your manual is later updated version without typo.

On Fri, 23 Apr 2021, 23:47 satbeginner, <castellcorunas@gmail.com> wrote:

Again sorry, no attachments...

I added my page to this album:

https://groups.io/g/TekScopes/album?id=262133

Leo

Op vr 23 apr. 2021 om 23:44 schreef satbeginner via groups.io
<castellcorunas=gmail.com@groups.io>:

This is what My manual says: (sorry for the poor picture..)
The last time I calibrated my 485 this worked...

Leo
[image: IMG_20210423_234002_01.jpg]

On Fri, 23 Apr 2021, 22:51 Ondrej Pavelka, <
info@vintageaudiorepairs.eu>
wrote:

Hello to the group,

Is anybody on here familiar closely with 485 calibration? In
particular
the Auto Focus section.

There is a time continuum breach making my brain go into feedback
loop
and
self destruct.

It's point 13) If I simplify it, it says put 3MHz in Channel 1,
display
nice 2 divisions high sinewave and adjust focus and astigmatism at
low
intensity for sharp trace. That works perfectly.
Next step is to raise intensity to 50V and check if focus bias does
anything, if it does you continue the procedure if it does not you
are
advised to skip forward to 13. This is where my brain melts. Because
13
is
definitely skip backwards and it says nothing about how to resolve
this
situation.

In my case focus bias does nothing with Z out voltage at all nor does
it
anything with actual focus.

Any ideas?


















Re: Cure tracer with digital scope

santa0123456
 

Long time ago, I posted pictures with a 7CT1N in a DSA602A in X/Y mode.

https://groups.io/g/TekScopes/photo/12992/165087?p=Name,,7CT1N,20,1,0,0

Funny mix of 7K and 11K series to make a digital (color) curve tracer. And you can store traces for comparison or even download them over GPIB.

Of course, the 7CT1N is not a 576...


Re: 485 super weak brightness control

Ozan
 

Hi Ondrej,
Great news that relays fixed many of the issues, congratulations.

As you know in 521 setting only B sweep is used so if you look at "B sweep from Q1236" on sheet <11> it should look the same as you press "A" or "B". Base node of Q1312 and Q1318 select A or B (should be in B in 521 regardless of switch), that node should be the same voltage in "A" or "B" in 521 mode. Base node of Q1358 and Q1356 select sweep or XY mode, should also stay the same in "A" and "B".

Once you know which node misbehaves you can find the root case, most likely in sheet <12> or one of the switches that feed into <12>.

Ozan


Guys,

New Relays arrived and nearly all is healed. When B is selected all works
flawlessly, when A is selected everything works up till the 521 range. In
521 it's not displaying properly. More in the video

I'm so happy it's nearly there now!

https://youtu.be/xCO4kJbXaMw






On Fri, 26 Mar 2021, 01:21 Raymond Domp Frank, <hewpatek@gmail.com> wrote:

On Fri, Mar 26, 2021 at 12:48 AM, Ozan wrote:


I agree sometimes stepping back and looking with fresh eyes helps. Let
us know
when you want to bounce off ideas again.
Ozan
I fully concur, Ozan.

Raymond






Re: 485 service manual is causing brain oscillations

Ondrej Pavelka
 

Yeah yours is fixed, I still think I have a problem there because it says
to reset it back to noted voltage but in my case the trimpot setting has no
impact on the voltage value.

Your manual is later updated version without typo.

On Fri, 23 Apr 2021, 23:47 satbeginner, <castellcorunas@gmail.com> wrote:

Again sorry, no attachments...

I added my page to this album:

https://groups.io/g/TekScopes/album?id=262133

Leo

Op vr 23 apr. 2021 om 23:44 schreef satbeginner via groups.io
<castellcorunas=gmail.com@groups.io>:

This is what My manual says: (sorry for the poor picture..)
The last time I calibrated my 485 this worked...

Leo
[image: IMG_20210423_234002_01.jpg]

On Fri, 23 Apr 2021, 22:51 Ondrej Pavelka, <info@vintageaudiorepairs.eu>
wrote:

Hello to the group,

Is anybody on here familiar closely with 485 calibration? In particular
the Auto Focus section.

There is a time continuum breach making my brain go into feedback loop
and
self destruct.

It's point 13) If I simplify it, it says put 3MHz in Channel 1, display
nice 2 divisions high sinewave and adjust focus and astigmatism at low
intensity for sharp trace. That works perfectly.
Next step is to raise intensity to 50V and check if focus bias does
anything, if it does you continue the procedure if it does not you are
advised to skip forward to 13. This is where my brain melts. Because 13
is
definitely skip backwards and it says nothing about how to resolve this
situation.

In my case focus bias does nothing with Z out voltage at all nor does
it
anything with actual focus.

Any ideas?














Re: Cure tracer with digital scope

Bert Haskins
 

On 4/23/2021 6:11 PM, wallydoc via groups.io wrote:
After a great deal of reading and lots of manipulation, (And a little luck) I finally hit on a combo that actually gives me a trace very much like the analog scope!

I never occurred to me to turn the sweep (horizontal control) on the digital scope. It's x-y right?? NO!
Could you elaborate on this?

What sweep setting are you using?

Maybe some pictures?

I now know the x-y mode is a math function of the two traces and not a true x-y plot.
You would have thought that would have registered with at least two remaining neurons since the x-y function is in the Math Menu.

These gol-darn new-fangled things actually can work well.

And the trace is Magenta!! Far Out!




FS: Tektronix TDS3064B with 4 new Keysight A2783 500 Mhz probes

Ken Eckert
 

The scope started life as a TDS3014B. I've done the upgrade in bandwidth to 600 Mhz and it has the TDS3ENG module that gives all the options.

I can provide photos showing the fast rise test on all 4 channels showing it meets the 600 Mhz BW.

Complete with cover and I think I have the manuals too.

If you are interested, send me a PM and we can go from there.


FS: Tektronix 1502B and 1503C TDR

Ken Eckert
 

I have a nice clean Tek 1502B and a 1503C for sale. A on very quick check, it looks like they both work fine.

The Tek 1502B LCD backlight doesn't does not work.The strip chart recorder on the 1502B was not tested.

Photos on request.

If you are interested please PM me and we can discuss it further


Re: Cure tracer with digital scope

wallydoc
 

After a great deal of reading and lots of manipulation, (And a little luck) I finally hit on a combo that actually gives me a trace very much like the analog scope!

I never occurred to me to turn the sweep (horizontal control) on the digital scope. It's x-y right?? NO!
I now know the x-y mode is a math function of the two traces and not a true x-y plot.
You would have thought that would have registered with at least two remaining neurons since the x-y function is in the Math Menu.

These gol-darn new-fangled things actually can work well.

And the trace is Magenta!! Far Out!


Photo IMG_20210423_234002_01.jpg uploaded #photo-notice

TekScopes@groups.io Notification <noreply@...>
 

The following photos have been uploaded to the 485 troubleshooting horizontal B sweep album of the TekScopes@groups.io group.

By: satbeginner <castellcorunas@...>


Re: 485 service manual is causing brain oscillations

satbeginner
 

Again sorry, no attachments...

I added my page to this album:

https://groups.io/g/TekScopes/album?id=262133

Leo

Op vr 23 apr. 2021 om 23:44 schreef satbeginner via groups.io
<castellcorunas=gmail.com@groups.io>:

This is what My manual says: (sorry for the poor picture..)
The last time I calibrated my 485 this worked...

Leo
[image: IMG_20210423_234002_01.jpg]

On Fri, 23 Apr 2021, 22:51 Ondrej Pavelka, <info@vintageaudiorepairs.eu>
wrote:

Hello to the group,

Is anybody on here familiar closely with 485 calibration? In particular
the Auto Focus section.

There is a time continuum breach making my brain go into feedback loop
and
self destruct.

It's point 13) If I simplify it, it says put 3MHz in Channel 1, display
nice 2 divisions high sinewave and adjust focus and astigmatism at low
intensity for sharp trace. That works perfectly.
Next step is to raise intensity to 50V and check if focus bias does
anything, if it does you continue the procedure if it does not you are
advised to skip forward to 13. This is where my brain melts. Because 13
is
definitely skip backwards and it says nothing about how to resolve this
situation.

In my case focus bias does nothing with Z out voltage at all nor does it
anything with actual focus.

Any ideas?










Re: 485 service manual is causing brain oscillations

satbeginner
 

This is what My manual says: (sorry for the poor picture..)
The last time I calibrated my 485 this worked...

Leo
[image: IMG_20210423_234002_01.jpg]

On Fri, 23 Apr 2021, 22:51 Ondrej Pavelka, <info@vintageaudiorepairs.eu>
wrote:

Hello to the group,

Is anybody on here familiar closely with 485 calibration? In particular
the Auto Focus section.

There is a time continuum breach making my brain go into feedback loop and
self destruct.

It's point 13) If I simplify it, it says put 3MHz in Channel 1, display
nice 2 divisions high sinewave and adjust focus and astigmatism at low
intensity for sharp trace. That works perfectly.
Next step is to raise intensity to 50V and check if focus bias does
anything, if it does you continue the procedure if it does not you are
advised to skip forward to 13. This is where my brain melts. Because 13 is
definitely skip backwards and it says nothing about how to resolve this
situation.

In my case focus bias does nothing with Z out voltage at all nor does it
anything with actual focus.

Any ideas?






Re: Cure tracer with digital scope

Bert Haskins
 

On 4/23/2021 4:36 PM, TomC wrote:
Digital scopes generally suck in X-Y mode. You may be out of luck.

Tom
The one I've been working on has been showing great promise as a curve tracer.





On 4/23/2021 10:24 AM, wallydoc via groups.io wrote:
I have a B+K curve tester that I can use with my Tex 475 quite nicely. I did get it to work with an HP 1980 scope but that is more complicated.
When I set up my Agilent 54810 dig scope to X vs Y all I get is junk.
Hopefully there is someway to get the dig scope to work with the old curve tester.
Any suggestions?

I still have that 5CP1 CRT for give away and also a CRT tester, if anyone is interested.
I am in Indianapolis IN

Wally KC9INK







485 service manual is causing brain oscillations

Ondrej Pavelka
 

Hello to the group,

Is anybody on here familiar closely with 485 calibration? In particular the Auto Focus section.

There is a time continuum breach making my brain go into feedback loop and self destruct.

It's point 13) If I simplify it, it says put 3MHz in Channel 1, display nice 2 divisions high sinewave and adjust focus and astigmatism at low intensity for sharp trace. That works perfectly.
Next step is to raise intensity to 50V and check if focus bias does anything, if it does you continue the procedure if it does not you are advised to skip forward to 13. This is where my brain melts. Because 13 is definitely skip backwards and it says nothing about how to resolve this situation.

In my case focus bias does nothing with Z out voltage at all nor does it anything with actual focus.

Any ideas?


Re: Cure tracer with digital scope

TomC
 

Digital scopes generally suck in X-Y mode. You may be out of luck.

Tom

On 4/23/2021 10:24 AM, wallydoc via groups.io wrote:
I have a B+K curve tester that I can use with my Tex 475 quite nicely. I did get it to work with an HP 1980 scope but that is more complicated.
When I set up my Agilent 54810 dig scope to X vs Y all I get is junk.
Hopefully there is someway to get the dig scope to work with the old curve tester.
Any suggestions?
I still have that 5CP1 CRT for give away and also a CRT tester, if anyone is interested.
I am in Indianapolis IN
Wally KC9INK


Re: Cure tracer with digital scope

Bert Haskins
 

On 4/23/2021 1:24 PM, wallydoc via groups.io wrote:
I have a B+K curve tester that I can use with my Tex 475 quite nicely. I did get it to work with an HP 1980 scope but that is more complicated.
When I set up my Agilent 54810 dig scope to X vs Y all I get is junk.
Hopefully there is someway to get the dig scope to work with the old curve tester.
Any suggestions?

I still have that 5CP1 CRT for give away and also a CRT tester, if anyone is interested.
I am in Indianapolis IN

Wally KC9INK
I am (slowly due to family issues ) working on this.

I have two digital scopes, a Tek and a Hantek and neither one is close to being useful on a CT.

I am working on a mod for one of my STM32F3 digital scopes that I think will work out nicely for this.

Full color and al sorts of other goodies to work with.

For the meantime though analog rules.

-Bert




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