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Re: A Way to (Sometimes) Repair Broken 22xx Knobs

DaveC <davec2468@...>
 

A photo would be great.

Dave

Sent from my iPhone

On Feb 17, 2013, at 8:46 AM, "Philip" <ndpmcintosh@...> wrote:

Well here is my first actual contribution to the group. I had to learn the hard way what most of you probably already know--NEVER REMOVE THE KNOBS FROM A 2200 SERIES SCOPE UNLESS YOU ABSOLUTELY HAVE TO.

I figured it would be easier to clean the front panel with the knobs removed (and it is) but I have experienced about a 50% breakage rate when removing the small knobs along the top and for the trigger. They are old and brittle. As has been pointed out, they are hard to find and not cheap when you do find them (although I was fortunate enough to talk a guy on eBay into selling me a lot of them for a pretty reasonable price).

So, I have been experimenting with ways to rescue the broken ones. What generally happens is one side of the little plastic retainer clip on the inside snaps off. One thing I have tried is drilling out an HP knob that looks exactly the same and figuring out how to secure it (these are available by the bushel for cheap at a local surplus store). No luck on that so far, but that is for another time.

What does mostly work is cutting a little piece of plastic tubing in the shape of the missing piece and sliding it into position with tweezers. It works best if the clip is completely broken off flush, but that is rare, so you have to cut the tubing to account for what ever part of the clip remains. The tubing I use is the flexible, clear plastic polyethylene Tygon type with an OD of 5/16in and a wall thickness of 1/64in.

They seem to pop back on pretty well. There is ever so slight an eccentricity when they turn but you'd really have to know what you were looking for to notice it.

I think it might even work better if the entire clip was missing and you might try removing it with a small grinding tool. Trying to break off the clip or remaining pieces has resulted in complete destruction of the knob. Let me know if you come up with any improvements or better ways to rescue a knob.



------------------------------------

Yahoo! Groups Links
A Way to (Sometimes) Repair Broken 22xx Knobs

Philip McIntosh
 

Well here is my first actual contribution to the group. I had to learn the hard way what most of you probably already know--NEVER REMOVE THE KNOBS FROM A 2200 SERIES SCOPE UNLESS YOU ABSOLUTELY HAVE TO.

I figured it would be easier to clean the front panel with the knobs removed (and it is) but I have experienced about a 50% breakage rate when removing the small knobs along the top and for the trigger. They are old and brittle. As has been pointed out, they are hard to find and not cheap when you do find them (although I was fortunate enough to talk a guy on eBay into selling me a lot of them for a pretty reasonable price).

So, I have been experimenting with ways to rescue the broken ones. What generally happens is one side of the little plastic retainer clip on the inside snaps off. One thing I have tried is drilling out an HP knob that looks exactly the same and figuring out how to secure it (these are available by the bushel for cheap at a local surplus store). No luck on that so far, but that is for another time.

What does mostly work is cutting a little piece of plastic tubing in the shape of the missing piece and sliding it into position with tweezers. It works best if the clip is completely broken off flush, but that is rare, so you have to cut the tubing to account for what ever part of the clip remains. The tubing I use is the flexible, clear plastic polyethylene Tygon type with an OD of 5/16in and a wall thickness of 1/64in.

They seem to pop back on pretty well. There is ever so slight an eccentricity when they turn but you'd really have to know what you were looking for to notice it.

I think it might even work better if the entire clip was missing and you might try removing it with a small grinding tool. Trying to break off the clip or remaining pieces has resulted in complete destruction of the knob. Let me know if you come up with any improvements or better ways to rescue a knob.
Need TDS5000 series system restore CD

testtech <testtech@...>
 

Greetings Group,

I am in need of the System Restore CD for the TDS5000 (non B) series scope. The instrument I have has a failed HDD. Any help appreciated!
Re: 2456B whole display moved up on the CRT

Bob Koller <testtech@...>
 

Does this affect all four channels? If so, I would suspect a problem in the vertical output, perhaps as simple as one of the CRT neck leads ha come off, or something in the vertical chain has failed. Channel switch or vertical output hybrid.


From: allegretto2a
To: TekScopes@...
Sent: Saturday, February 16, 2013 8:17 PM
Subject: [TekScopes] 2456B whole display moved up on the CRT

 
My trusty 2465B now has a vertically offset display on the CRT. The bottom of the normal display is now at mid-point. Has anyone seen and solved this problem? Where do I look for the source of this problem?
Thanks, AL
465 Repair & Refurb on Hacked Gadgets

Bill Higdon
 

Re: Tektronix A6901 ground isolation monitor

PA4TIM
 

I tested it today, first it started beeping, so I turned the plug around ( in th US and UK with 3 pin plugs you can not do that so I suppose phase and zero are allway connected according a standard. Here we can plugin as we like, but this thing needs to be plugged in the right way. 

Then I connected a non grounded lightbulb. Turned the powerswitch, and pressed the right button and click, the ground fault breaker switched so I was in the dark. 

Then I removed the Termistor like you told and now I can power the lamp. I can do this in the grounded and isolated position ( tried an indtrument too). So that worked fine. 

I pushed the left red test button and I was in the dark again. Main groundfault breaker tripped a gain. Then I found a switch at the bottom that was in 5 mA. When I switch that to 0.5 mA and the 6901 in isolated position, pushing the button only switched of the load. So this is what I want. I now can probe in an isolated DUT but if I cause a short or there is a fault in the DUT the DUT switches off. Like when using the 1:1 transformer and series lightbulb.

If I use it in grounded position everything works but if I then push the left testbutton the main ground fault breaker still trips. But I think this is correct because that is what you want when using something grounded.

Hope you find some time to copy some manual pages. 

Thanks for the advise, i would not had found this myself without a circuit.

Slightly on-topic:

I have a 230-110V transformer with a red light on it. It has some error message written on it. It burns if the transformer is switched on, it goes out if the rail powers down. But it gave 15V and I use it whithou problems, so I thought the error was if the light went out,  I now tried the same thing and if I turn the plug the light goes out. But the strange thing is that when I switch of that powerrail ( a lot mains sockets on a row in groups with a switch at each group, like you use for lights) , the red light goes on again) it only switches one line so I think it noe switches the nul instead of phasel. I had an instrument that did the same. With power on the rail and the HP switched off, the powerlight was also off, but both switced off made the light glow dim. So I think I have to reverse those connections and use that transformer to test if all sockets ( about 50) are connected the same way. 

But i then still do not know if the instruments are connected the same way and if this matters. In a lot of countrys this seems to be important but not over here. Strange, there should be a reason or advantage ( noise or so ?) for that I guess. Otherwise why the light on the transformer and the test for this on the A6902. 

Fred PA4TIM

Op 14 feb. 2013 om 10:47 heeft "Craig Sawyers" <c.sawyers@...> het volgende geschreven:

 

> So if it does not start you should have a ground impedance problem ( or is it not the right test for modern groundfault breaker circuits ( those things in cabinet where your powerlines enter the house) i believe in old houses and some countrys they do not have them)

Correct - it is not compatible with precisely those. In "old" wiring, where there was a simple fuse-box there would be no problem. But in modern cabinets (ie any time in the last 30-odd years), it takes out the breaker. Turn the A6901 on and bang! Everything gets turned off.

> But if you have the manual, would you mind making a scan for me ? ( the operation part is most important)

This weekend is a possibility. What language? There are English, German, French, Spanish and Japanese operation sections. Service information is in English only.

Craig
Re: Question

Tom Miller
 

I think they are 0.125 inch diameter. Hobby shops carry 1/8 inch carbon fiber rods that I have found to be non-conductive and it works for that shaft.
 
Regards,
Tom
 

----- Original Message -----
Sent: Saturday, February 16, 2013 10:04 PM
Subject: Re: [TekScopes] Question

 

On 02/16/2013 09:14 PM, Cliff White wrote:
 

Or actually two. I have a broken fiberglass rod for the vertical position control on my 466. Would there be any ill effects of replacing it with a wood skewer? They're the same diameter.

In my town I just run over to the florist and pick what I want from the
rods that they use in floral arrangements.
I don't know ( or care ) if these are fibreglass but they are
tough, cheap, and easy to shape using a grinder.
Please wear protective gear,  I don't think that the dust 
would be good for either your eyes or lungs.


Second, will a 465B front cover fit a 466?





 

--
Respectfully,
Cliff White, W5CNW
w5cnw@...

2456B whole display moved up on the CRT

allegretto2a
 

My trusty 2465B now has a vertically offset display on the CRT. The bottom of the normal display is now at mid-point. Has anyone seen and solved this problem? Where do I look for the source of this problem?
Thanks, AL
Re: Question

teamlarryohio
 

Bert Haskins <bhaskins@...> wrote:
On 02/16/2013 09:14 PM, Cliff White wrote:

Or actually two. I have a broken fiberglass rod for the vertical
position control on my 466. Would there be any ill effects of
replacing it with a wood skewer? They're the same diameter.
In my town I just run over to the florist and pick what I want from the
rods that they use in floral arrangements.
I don't know ( or care ) if these are fibreglass but they are
tough, cheap, and easy to shape using a grinder.
Please wear protective gear, I don't think that the dust
would be good for either your eyes or lungs.


Second, will a 465B front cover fit a 466?
Yes
Re: Question

Bert Haskins
 

On 02/16/2013 09:14 PM, Cliff White wrote:
 

Or actually two. I have a broken fiberglass rod for the vertical position control on my 466. Would there be any ill effects of replacing it with a wood skewer? They're the same diameter.

In my town I just run over to the florist and pick what I want from the
rods that they use in floral arrangements.
I don't know ( or care ) if these are fibreglass but they are
tough, cheap, and easy to shape using a grinder.
Please wear protective gear,  I don't think that the dust 
would be good for either your eyes or lungs.


Second, will a 465B front cover fit a 466?


 


--
Respectfully,
Cliff White, W5CNW
w5cnw@...

Question

Cliff White
 

Or actually two. I have a broken fiberglass rod for the vertical position control on my 466. Would there be any ill effects of replacing it with a wood skewer? They're the same diameter.

Second, will a 465B front cover fit a 466?
 


--
Respectfully,
Cliff White, W5CNW
w5cnw@...

585A on Dallas Craigslist

sipespresso <sipespresso@...>
 

I have no affiliation with the seller.
http://dallas.craigslist.org/mdf/ele/3621025839.html
-Kurt
Re: Frequency response flatness in conventional sampling (say 7S11/S

David Hess
 

The blow-by effect on frequency response could be tested. Grossly
misadjust it deliberately and see if the frequency response changes. I
found it to be the easiest thing to calibrate on my S-4 sampling heads
so I would not worry about temporarily misadjusting it.

I would also compare two different types of sampling heads like an S-2
and S-4 which have significantly different transient response
characteristics in the 10ns range do to design and see if they agree.

I may try the above with an S-1 and S-4 and my SG503 just to see what
kind of results I get.

On Sat, 16 Feb 2013 10:48:35 -0000, "Albert" <aodiversen@...>
wrote:

Hi David,

The step response of my S-4 is very similar to the pictures shown in the cal proc of the manual. Overshoot from 400 ps to 25 ns is specified as 10% or less. Blow-by compensation adjusts the level or trend after 25 ns. Both overshoot and blow-by might well affect the frequency response (far) below 1 GHz I think.
The awkward thing is that we always need something that's again better than what we already have. I have to trust pulse flatness of my S-52 and 264 (also Square Wave for S-2 blow-by) but in reality I have no means to check that. In S-1 and S-2 the blow-by adjustment has considerable effect, so if your S-1 shows no blow-by then you or a previous owner did a good calibration job. I'm not sure I ever re-adjusted my S-4.

I did many amplitude measurements on my 067-0532-00, 3 MHz and 60-500 MHz, using 7T11A/7S11/S-2. At 1 Vpp the amplitude changes are within 1% (that is max - min) over the whole frequency range, including the separate 3 MHz. At 3 Vpp (connected via GR 2X attenuator) still within 2%.
That looks very nice, but in theory a non-flat response of the S-2 could compensate for a non-flat output of the signal generator. I used an S-2 to eliminate a GR to SMA adapter and also because the S-2 allows for internal triggering.

Albert


--- In TekScopes@..., David <davidwhess@...> wrote:

I do not have any in dependant confirmation but I suspect given the
relatively low frequencies involved for the sampling heads up to 5%
loss that they will be very close to ideal. I do not know of a better
way to calibrate for a constant level that does not require something
else already calibrated to a better standard except for a thermal RMS
based design which itself can be calibrated at DC.

If you have even an unleveled microwave signal source, you could use
it to find the first null in the sampler frequency response which
would tell exactly what the sample gate time is.

Do you mean overshoot or blow-by? I know my S-4 sampling heads have a
lot of blow-by aberration or whatever that is at about 10ns but show
ideal pulse response as far as I can test. My working S-1 shows no
blow-by with the same input pulse but my best flat level pulse
generator while clean is not fast enough for the S-4.

On Fri, 15 Feb 2013 22:35:37 -0000, "Albert" <aodiversen@...>
wrote:

Hi David,

In my response to Ed I said something about VSWR; that crossed your message.
Your calculations (indeed needing the famous sin(x)/x) assume a perfect rectangular windowing function. Do you have any reference for how good or bad this approach might be in practice? The overshoot in step response of my S-4 is in conflict with this theoretical approach.

Albert

--- In TekScopes@..., David <davidwhess@> wrote:

I think using a sampling oscilloscope for flatness calibration is a
great idea. The sampling heads are both very high bandwidth and have
a very predictable frequency response. The weakest links will be the
SWR match and termination but that applies to any system. You can do
away with cable losses by using a sampling head extender.

If you take the 3db bandwidth numbers I posted earlier and divide by
4, that is the point where the sample head output will be down by 2%.
The second number shown is where they will be down by 1%:

S-1 260 MHz 190 MHz
S-2 1.18 GHz 869 MHz
S-4 3.60 GHz 2.61 GHz
S-6 2.99 GHz 2.17 GHz

I think this is the first time I have had a need to do math involving
a sin(x)/x function.
Re: 555 on Detroit craigslist

Jim <n6otq@...>
 

Hmm, I had a ham radio friend whose tomcat used to sleep on top of his vintage HF rig -- until one day it let some cat tinkle dribble out.

After that, it wouldn't even go in the ham shack.

73
Jim N6OTQ

From: Paul Amaranth
To: TekScopes@...
Sent: Saturday, February 16, 2013 12:02 PM
Subject: Re: [TekScopes] 555 on Detroit craigslist

I asked him about that.  It's a demon gremlin, he says he used it
as a mad scientist prop in a haunted house.

Would be a great cat bed though.  I used to have a big crt terminal
and my cat used to sleep on top of it while I was working.
Re: Tek 2245A Backup Battery Exchange -- Any special steps?

David Hess
 

I have a 2246 and 2247A. As far as I know, the backup battery only
matters for the configuration settings so no special precautions are
needed when changing it.

The PDF files I have for these oscilloscopes are all scanned images so
text searching is not possible with them. I sometimes use a free
online service to remove the restrictions but only so I can extract
the schematics, clean them up, and then print them out.

On Sat, 16 Feb 2013 15:27:08 -0000, "chuckcurran53012"
<ccurran@...> wrote:

Hello Tek Scopes Group:

I need to change the backup battery in my 2245A. I am not aware of any special steps required.

Can I simply remove the old and solder in a new one? Or, will I mess something up when the battery voltage is removed?

I am also looking for a 2245A service manual. The one I found on line is a locked pdf file, so no searches can be performed. Might anyone be aware of a copy that is not a "locked", but a searchable file?

Thanks,

Chuck
Re: 555 on Detroit craigslist

Paul Amaranth
 

I asked him about that. It's a demon gremlin, he says he used it
as a mad scientist prop in a haunted house.

Would be a great cat bed though. I used to have a big crt terminal
and my cat used to sleep on top of it while I was working.

On Sat, Feb 16, 2013 at 09:03:10AM -0800, Daniel Koller wrote:
his wife is getting adamant about??getting rid of it;

?? ??Is that why there is a wig on it? ??Or is that a cat? ??Never considered that before, but it's a nice place for a cat to sleep.

Dan



________________________________
From: Paul Amaranth <paul@...>
To: TekScopes@...
Sent: Saturday, February 16, 2013 11:48 AM
Subject: [TekScopes] 555 on Detroit craigslist


??
555 dual beam scope with power supply and cable

http://detroit.craigslist.org/mcb/atq/3603048849.html

I got a note from the seller, his wife is getting adamant about
getting rid of it; he's open to offers. Anyone want to try
$50?

--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... | Unix & Windows


--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... | Unix & Windows
Re: 555 on Detroit craigslist

Robert Fisher
 

This is pretty strange. Attached is an enhanced photo of the " thing" atop the 555

From: Daniel Koller
To: "TekScopes@..."
Sent: Saturday, February 16, 2013 12:03 PM
Subject: Re: [TekScopes] 555 on Detroit craigslist

 
>his wife is getting adamant about getting rid of it;

   Is that why there is a wig on it?  Or is that a cat?  Never considered that before, but it's a nice place for a cat to sleep.

Dan


From: Paul Amaranth
To: TekScopes@...
Sent: Saturday, February 16, 2013 11:48 AM
Subject: [TekScopes] 555 on Detroit craigslist

 
555 dual beam scope with power supply and cable

http://detroit.craigslist.org/mcb/atq/3603048849.html

I got a note from the seller, his wife is getting adamant about
getting rid of it; he's open to offers. Anyone want to try
$50?

--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... | Unix & Windows





Re: Strange AEROVOX cap on my 564

Don Black <donald_black@...>
 

Thanks for that interesting story John, there are some weird things around. As to the cause; I think it's a full moon. At least until someone else comes up with a better explanation. And the moral of the story. Too much washing can be dangerous, if not for that washing machine global warming might have been solved.
 Cheers, Don Black.

On 16-Feb-13 11:13 PM, John wrote:
 

And sometimes become a voltage source i.e. they become a battery. That
can really throw out equipments operation. You can measure the voltage
with a voltmeter, it's steady, not just a charge that will leak away.

==================================================

Don Black posted above:

Reply:: Don,and Group members: I've hesitated for a long time to
mention this same
observation here, but Dons given me the courage to say its true for
some Tantalum (bead) caps too !
And not used ones either, but NOS!
Years ago, when people still used transistors for design work
I volunteered to design and make a shaped freq /amplitude response amp
for a medical app.which had to be AC coupled
This was a freeby, but most of the stuff was bought new and a PC board made
The only "old" parts I used were tantalums made by a well know manufacturer
in the UK, blue bead STC tantalums which came in packs of 5 in sealed
waxed paper bags .
I had a few of those bags unopened and used these due to there high
quality reputation (and cost) and as
they were still sealed. On populating the board , test time showed
each transistor either
saturated or near saturation. The amp was simple enough in concept , so
had I assembled the
board wrong? Careful check showed all OK, including correct
polarities fitted
I had pre checked the transistors for gain at 1kHz and leakage and all
other parts except the caps before fitting (being a
medical app) and these were all fine.
The culprit was quickly traced to the Tant caps......each one was a
battery putting out several
hundred millivolts all on their own !
Removing the caps I twisted their leads together while I had dinner.
Returning about an hour later
the caps were still generating about the same voltage after untwisting
their leads., all of which came up withon a few seconds
Putting them in series added the voltages enough to dimly light a
"grain of wheat" filament lamp.
Shorting them overnight they gave , again, the same battery effect when
un-shorted.
IAll the NOS stocks I had of these were the same (blue STC bought at
the same time) The packets of caps would be
around 20 years old when bulk .bought new and left over from an old project
I put them in a matchbox with leads shorted and carried them around for
a while, showing them to various
people at work and in various labs for a year , where most thought it
was some trick of mine,
Few actually believed it.
Eventually, the caps still giving out a steady voltage,. I accidentally
put my trousers in the wash
with the matchbox still in its pocket which corroded off the leads
due to the washing powder used.
Ive often thought that if I had given them to a battery manufacturer
maybe the secret would have been
discovered and "infinite" life batteries might be in use today!!
(and maybe I would have been richer too)

Anyone brave enough to have seen the same effect and talk about it?
Electro chemists might have a rational explanation?
John
Re: 555 on Detroit craigslist

Daniel Koller
 

>his wife is getting adamant about getting rid of it;

   Is that why there is a wig on it?  Or is that a cat?  Never considered that before, but it's a nice place for a cat to sleep.

Dan


From: Paul Amaranth
To: TekScopes@...
Sent: Saturday, February 16, 2013 11:48 AM
Subject: [TekScopes] 555 on Detroit craigslist

 
555 dual beam scope with power supply and cable

http://detroit.craigslist.org/mcb/atq/3603048849.html

I got a note from the seller, his wife is getting adamant about
getting rid of it; he's open to offers. Anyone want to try
$50?

--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... | Unix & Windows



555 on Detroit craigslist

Paul Amaranth
 

555 dual beam scope with power supply and cable

http://detroit.craigslist.org/mcb/atq/3603048849.html

I got a note from the seller, his wife is getting adamant about
getting rid of it; he's open to offers. Anyone want to try
$50?


--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... | Unix & Windows
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