Date   

Re: Corrosion Damage – TM500 Plugins

-
 

I've been told that that foam breaks down and releases some kind of
Fluorine gas or compound. Whatever it is, it seems to attack just about
every kind of metal including stainless steel. Also gold, or possibly it
penetrates the gold layer and attacks the underlying metal.

There was a long discussion about this on the list a couple of months
ago.

On Sat, Apr 24, 2021 at 3:58 AM <christopherbath@hotmail.com> wrote:

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






465M

Ananda
 

Gents,

Does anyone have any parts for a 465M by any chance? I had my scope start blowing the F558 fuse recently. It blows the fuse if the anode is connected. I had a spare CRT and that does the same thing. I also ruled out the EHT. Now it seems like something in the HV regulator area (per the service manual where the -2kV is controlled) has failed. I am yet to check the components there but there are some diodes that seem to be rare.

Any pointers/help is much appreciated.

Thanks in advance.


Re: 465 scope component question

Bill
 

Thank you. Yes it is blue. Mine has been physically damaged in the past so I need to replace it. I've also found several shorted Tantalums that I will be replacing. Good thing I enjoy tinkering!!
Bill


Re: 465 scope component question

Dave Peterson
 

C1477?
I have those too. Blue ceramic? The second larger one parallel to C1474 goes over to R1476/CR1476. Looks like C1477 to me.
Dave

On Saturday, April 24, 2021, 08:39:05 AM PDT, Bill via groups.io <ko4nrbs=yahoo.com@groups.io> wrote:

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


Good storage solution for collection of 500-series plugins?

Jonathan Pyle
 

I currently have four plugins for my RM45A (545A), which means three of my plugins are always lying around somewhere collecting dust.

It would be great if there was a bookshelf or rack where I could store plugins when I wasn't using them, where they would be enclosed on five sides and thus protected from dust and other dangers.

Does anyone have a good solution for storing 500-series plugins? I was hoping for something inexpensive rather than a vintage scope cart that would cost a lot to ship. Maybe someone has found an Ikea-ish organizer that happens to have compartments that are the perfect size for 500 series plugins?


Re: Waking a slumbering 475

Jim Adney
 

On Sat, Feb 13, 2021 at 05:41 AM, Michael A. Terrell wrote:

You should have listened to Jim.
I remember Jim Yanik. He was one of the many good contributors to the sci.electronics newsgroup. I just googled on James Yanik obituary and got only one hit for someone who was only 45 years old, in Rochester, Michigan. So our Jim may still be around. If so, I wish him well.

One of the main reasons to start OLD electronic devices on a Variac was the fact that they were probably made for lower line voltages than are common today. As I type this, my line voltage indicator reads 128 VAC, which is significantly higher than the 110 that things were made for in 1920-30. A lot of old, irreplaceable power transformers died when they got connected to modern power and their cores saturated.

One thing to keep in mind if you DO decide to power up some old equipment slowly on a Variac is that almost nothing is going to happen until you're up to 60% or so. That's because a rectifier filament running at 50% is probably still putting out close to zero emission. You may still be warming up the power transformer and driving off accumulated moisture, which can be a good thing, but if you're thinking about the power supply filter caps, they're likely to come up rather quickly as you get closer to 80-90%. You can probably tell something by watching the tube filaments.

Putting an incandescent lamp in series is a good troubleshooting method that can save you a lot of blown fuses. I think this was a method promoted in some audio amplifier kits, perhaps Dynaco. I never built any Dynakits, but the Heathkits I built never mentioned this. I probably picked it up from someone on one of the newsgroups I followed. As a result of that, I put together the gear shown here:

https://groups.io/g/TekScopes/photo/262268/3213632

This was built from a standard fused outlet cover and a metal 2x4 box. If I had it to do over again, I'd cut a hole for a standard modular plug instead of the long cord, just to save space and use a modern standard cord. It would have been even better if I could have found a 4x4 cover with the Edison socket, an outlet, and a switch. I don't know if such things exist.

I can switch in different wattage light bulbs appropriate for the wattage of whatever I'm trying to troubleshoot. If I need more wattage, I can add the Y adaptor and put 2 bulbs in parallel. Basically, you want the fully lit bulb current to be less than the fuse rating. Keep in mind that cold tungsten bulbs will pass much more current than when hot. This makes them very nice fault current limiters. A selection of bulbs (15, 50 or 60, 100, 150, 150 Watts) and the Y adaptor will let you use this on almost anything you might need to work on.

thanks for reading,


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@...>

4841 - 4860 of 186431