Date   
Re: 555 Attributes, facets, benefits and General Discussion

Morris Odell
 

It sounds like a 502, which was my first Tek and I still have it stored away. It is a double beam with one timebase common to both beams. It's a little bit smaller than a 545. The vertical amps are built in and use very high quality low noise tubes that audiophooles would kill for. It was intended for biomedical use and the VAs are very sensitive, down to 100 uV/div and the bandwidth varies from 500 KHz down to 100 KHz at maximum sensitivity. I appreciated it at the time when I was working on audio stuff and RTTY modems etc but it's not really practical for other things.

Morris
--------------------------------
Roy wrote:

Some decades ago (2 or 3) I had a different dual trace scope but am unsure of the model number. It was the size of the 545 with no separate power unit. It had two vertical channels and time base without any plug-ins as I remember. The bandwidth was modest, meant for medical/physiology use.

It must have been the 502. Maybe I will discover it buried in my long-neglected storage unit.

Re: Tektronix 2467B Auto Measure Faulty?

Chuck Harris
 

Not really. U500 is a pretty high failure item. I suggested the
measurements around CHN5B, and CHN5A pins because they are the way
it is driven for automatic tests. The transistor that drives CHN5B
sometimes fails... but not as often as U500.

The transistors around U500, and U975 are just GP NPN and PNP transistors
like 2N3904 and 2N3906.. They are very reliable... and you should be
able to find them in your TV repair store.

-Chuck Harris

Leandro Lindemann via Groups.Io wrote:

Chuck, I'll take this and ask one more question:

In addition to the U500, any other suspicious ICs that you can buy to take advantage of the shipment from the USA to Brazil?

Thanks



Re: Tektronix 2467B Auto Measure Faulty?

Chuck Harris
 

Generally, I go right from the AUTO voltage measurement failure
to cleaning U500, to replacing U500.... but then, I have spare
scopes that I keep to verify failed hybrids..

If you want to be doubly sure, go to the schematic page for the
A/B sweep, and trigger hybrid, and notice that there are hexagons
with numbers and pointers on the schematic. These are test points,
and there is an earlier page that shows the settings the scope
should be in, and what the waveform at the test point should look
like.

Look at the test points: 28, 46, 36, 29, 34 and 42.

-Chuck Harris

Leandro Lindemann via Groups.Io wrote:

Chuck.

I will order this IC on Ebay then.

Before ordering the CI, would you like me to do some other measure in the scope? I have another scope (hitachi) that I can use for this.

Thanks for your help.

Re: Tektronix 2467B Auto Measure Faulty?

Leandro Lindemann
 

Chuck, I'll take this and ask one more question:

In addition to the U500, any other suspicious ICs that you can buy to take advantage of the shipment from the USA to Brazil?

Thanks

Re: Tektronix 2467B Auto Measure Faulty?

Leandro Lindemann
 

Chuck.

I will order this IC on Ebay then.

Before ordering the CI, would you like me to do some other measure in the scope? I have another scope (hitachi) that I can use for this.

Thanks for your help.

Re: Tektronix 2467B Auto Measure Faulty?

Chuck Harris
 

My next step after cleaning U500 is to replace it with
a known working U500 from one of my test scopes.

They are a very common failure part.

-Chuck Harris

Leandro Lindemann via Groups.Io wrote:

Hello Chuck.

I removed the IC U500. I cleaned with Deoxit D5 its terminals and its socket.

Unfortunately it didn't. Problem persist.

Then I removed the IC PAL, cleaned his contacts and the problem persists.

I will leave the scope open, hoping that I have time to continue helping me.

Thank you.



Re: Tektronix 2467B Auto Measure Faulty?

Leandro Lindemann
 

Hello Chuck.

I removed the IC U500. I cleaned with Deoxit D5 its terminals and its socket.

Unfortunately it didn't. Problem persist.

Then I removed the IC PAL, cleaned his contacts and the problem persists.

I will leave the scope open, hoping that I have time to continue helping me.

Thank you.

Re: Tektronix 2467B Auto Measure Faulty?

Chuck Harris
 

Yes.

Leandro Lindemann via Groups.Io wrote:

I understood your explanations Chuck.

I will do this today, and I will return with the result.

With much hope of being something simple, like bad contact.

In this case, the hybrid is the U500, correct?

Thank you.

Leandro Lindemann.



Re: 547 scope HV transformer problem. One practical solution.

 

I have now ended the resuscitation from 40 years hibernation of my 547 scope. I could not be more pleased with it.

It has now inside an added little centrifugal blower fan that cools the HV supply. This has solved the classical HV transformer problem, that caused it to fail after 10 minutes.
This internal cooling was not easy, since the HV supply on the top left back corner is so removed and inaccessible to any air flow.
I removed the big metallic electrolytic cap. C802 so the hole left in its place is an opening to the metal enclosure, and replaced this cap with a small modern equivalent.
I cut a large opening into the front plastic box in front of the transformer to leave it exposed to incoming air.
I placed the blower in the space behind the vertical amplifier, and made an air conduit with plastic sheet, paper tubing, etc. around the CRT neck, then through the hole left by the capacitor, to the opening of plastic box in front of the transformer, a messy fix that I may improve some day when I am motivated. The plastic cover of the HV transformer, diodes, is now left off. Messy, but it works, and I am the only one aware of it.

In gratitude for working well again, I eased the strain on the supply by lowering the HV from 1850 to 1750 volt, a 5% change I don't notice on the screen, and I readjusted the gains of the horizontal and vertical amplifiers.
To further ease the work of the 6AU5 oscillator tube I lowered the supply voltage to the unit from the 325 unreg by 110 volt with a string of zener diodes.
Finally, to let the scope run cooler I changed the selector of line supply to the input transformer taps from MED to HI, since my home power is about 120 VAC.

If the HV transformer starts failing again after some decades in the future, I might not be around anymore to notice. In the meantime, the 547 is in my office on a cart, together with two TM504 supply boxes with miscellaneous plugins. I won't be able to resist powering up the instruments every day just to see the nice traces on the oscilloscope screen.

Re: Tektronix 2467B Auto Measure Faulty?

Leandro Lindemann
 

I understood your explanations Chuck.

I will do this today, and I will return with the result.

With much hope of being something simple, like bad contact.

In this case, the hybrid is the U500, correct?

Thank you.

Leandro Lindemann.

Re: Tektronix 2467B Auto Measure Faulty?

Leandro Lindemann
 

I understood your explanations Chuck.

I will do this today, and I will return with the result.

With much hope of being something simple, like bad contact.

In this case, the hybrid is the U500, correct?

Thank you.

Leandro Lindemann.

-----Mensagem Original-----
From: Chuck Harris
Sent: Wednesday, February 26, 2020 2:54 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tektronix 2467B Auto Measure Faulty?

It doesn't take much care to work with the
"finned" hybrids. They each have 4, #4-40 nuts,
with captive star lock washers, that hold them
to the socket. Some of the hybrids use a hex
standoff as one of the nuts...

To remove the nuts, either use a finger to
press the middle of the hybrid, and just spin
the nuts off, or if that is too many hands,
remove two diagonal nuts, and then loosen the
remaining two diagonal nuts 3 or 4 turns at a
time.

To put the hybrids back, you will need to use
both hands. One to arrange, and press the
hybrid into the socket, so its aluminum fins
contact the board on all sides.. and at the
same time, put on a diagonal pair of nuts to
finger tight. I use a plastic nut starter to
make this easier. The nut starter stretches to
fit the nut snugly, when you press it onto a nut
that is laying on your bench...

Then the other diagonal pair, and then tighten
all 4 nuts to just 1/4 turn past contact.

The only danger to the hybrids is if you tighten
the nuts when one side is hung up... that will break
the ceramic substrate. That is why you hold the
hybrid down against the board before you put on
a diagonal pair of nuts.

-Chuck Harris

leandro.lindemann via Groups.Io wrote:
Hello Chuck.

First of all, thank you very much for helping me.

Thank you also for informing that you were using the cursors in the wrong way. I learned that now.

Regarding hybrid ICs, I never worked with them. To remove them, and do a cleaning with DeoxitD5, is it necessary any extra care? Honestly they are intimidating, the fear of damaging them and failing to replace them is enormous.

I will wait for your answer on this before I do the cleaning.

I will hope that the problem of my dear 2467B is badly contacted.

Big hug and thank you very much.



Re: Upcoming Stuff Day event at Sphere Research

stevenhorii
 

Walter,

Please advise me of when the "stuff day" is to take place and when you post
listings of what stuff is up for sale. I can't make the trip, but I will
consider bidding online.

Regards,

Steve Horii

On Wed, Feb 26, 2020 at 12:51 PM walter shawlee <@walter2>
wrote:


The next stuff day event is tentatively set for saturday May 2nd.
this time seems clear for most people, but let me know if there's a
problem.

This year we will also have "remote" stuff day, where those from far away
can also get items when the initial stuff day event is over, or reserve
them in advance.
This may prove handy for those who just can't travel to the wilds of BC.
Really large and heavy items
will be excluded, however. lots of nifty HP items in particular this year,
plus a beautiful Tek 500Mhz
7934 real time storage scope. Also a huge pile of spare boards for HP and
Tek gear, and lots of tubes and CRTs, including Tek and HP CRTs.

The reason for excluding heavy items from shipping is that I broke my
right shoulder 6 weeks ago, and still have 3 months of physio to get back
in good condition. That just makes shipping large stuff a non-starter for
me right now. I will be relying on local volunteers to help move some of
the heavy stuff and help with set up and prep. Anybody interested, or
amateurs wanting trunk sale space, please let me know.

There will be things for everybody, from exotic tools (air tools to
chassis punches and top tier hand tools) and bulk hardware to every
possible kind of electronics, as well as microscopes, telescopes, microwave
gear, breadboards and interesting free items of all kinds. And yes, lots
of parts.

We may also get some local radio amateurs to joint in a trunk sale
alongside stuff day as before, so that will add some diversity, plus we
have a bunch of great RF and shortwave gear of our own to add.

Let us know if you need a spot to park your sleeping bag if you are
arriving early, guests are welcome.
we are in West Kelowna, BC, about 4 hours drive from Vancouver. We can
take Visa/MC and paypal as well, to make things easier.

all the best,
walter (walter2 -at- sphere.bc.ca)--

Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend
on us.
We are not the only experiment. (R. Buckminster Fuller)



Re: Tektronix 2467B Auto Measure Faulty?

Chuck Harris
 

It doesn't take much care to work with the
"finned" hybrids. They each have 4, #4-40 nuts,
with captive star lock washers, that hold them
to the socket. Some of the hybrids use a hex
standoff as one of the nuts...

To remove the nuts, either use a finger to
press the middle of the hybrid, and just spin
the nuts off, or if that is too many hands,
remove two diagonal nuts, and then loosen the
remaining two diagonal nuts 3 or 4 turns at a
time.

To put the hybrids back, you will need to use
both hands. One to arrange, and press the
hybrid into the socket, so its aluminum fins
contact the board on all sides.. and at the
same time, put on a diagonal pair of nuts to
finger tight. I use a plastic nut starter to
make this easier. The nut starter stretches to
fit the nut snugly, when you press it onto a nut
that is laying on your bench...

Then the other diagonal pair, and then tighten
all 4 nuts to just 1/4 turn past contact.

The only danger to the hybrids is if you tighten
the nuts when one side is hung up... that will break
the ceramic substrate. That is why you hold the
hybrid down against the board before you put on
a diagonal pair of nuts.

-Chuck Harris

leandro.lindemann via Groups.Io wrote:

Hello Chuck.

First of all, thank you very much for helping me.

Thank you also for informing that you were using the cursors in the wrong way. I learned that now.

Regarding hybrid ICs, I never worked with them. To remove them, and do a cleaning with DeoxitD5, is it necessary any extra care? Honestly they are intimidating, the fear of damaging them and failing to replace them is enormous.

I will wait for your answer on this before I do the cleaning.

I will hope that the problem of my dear 2467B is badly contacted.

Big hug and thank you very much.



Upcoming Stuff Day event at Sphere Research

 

The next stuff day event is tentatively set for saturday May 2nd.
this time seems clear for most people, but let me know if there's a problem.

This year we will also have "remote" stuff day, where those from far away
can also get items when the initial stuff day event is over, or reserve them in advance.
This may prove handy for those who just can't travel to the wilds of BC. Really large and heavy items
will be excluded, however. lots of nifty HP items in particular this year, plus a beautiful Tek 500Mhz
7934 real time storage scope. Also a huge pile of spare boards for HP and Tek gear, and lots of tubes and CRTs, including Tek and HP CRTs.

The reason for excluding heavy items from shipping is that I broke my right shoulder 6 weeks ago, and still have 3 months of physio to get back in good condition. That just makes shipping large stuff a non-starter for me right now. I will be relying on local volunteers to help move some of the heavy stuff and help with set up and prep. Anybody interested, or amateurs wanting trunk sale space, please let me know.

There will be things for everybody, from exotic tools (air tools to chassis punches and top tier hand tools) and bulk hardware to every possible kind of electronics, as well as microscopes, telescopes, microwave gear, breadboards and interesting free items of all kinds. And yes, lots of parts.

We may also get some local radio amateurs to joint in a trunk sale alongside stuff day as before, so that will add some diversity, plus we have a bunch of great RF and shortwave gear of our own to add.

Let us know if you need a spot to park your sleeping bag if you are arriving early, guests are welcome.
we are in West Kelowna, BC, about 4 hours drive from Vancouver. We can take Visa/MC and paypal as well, to make things easier.

all the best,
walter (walter2 -at- sphere.bc.ca)--

Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on us.
We are not the only experiment. (R. Buckminster Fuller)

Re: Tektronix 2467B Auto Measure Faulty?

Leandro Lindemann
 

Thanks for the link.

Re: Tektronix 2467B Auto Measure Faulty?

Leandro Lindemann
 

Hello Chuck.

First of all, thank you very much for helping me.

Thank you also for informing that you were using the cursors in the wrong way. I learned that now.

Regarding hybrid ICs, I never worked with them. To remove them, and do a cleaning with DeoxitD5, is it necessary any extra care? Honestly they are intimidating, the fear of damaging them and failing to replace them is enormous.

I will wait for your answer on this before I do the cleaning.

I will hope that the problem of my dear 2467B is badly contacted.

Big hug and thank you very much.

Re: Tektronix 2467B Auto Measure Faulty?

Chuck Harris
 

You are looking at the military service manual... it is not the best
manual to have. The US military standardized on the Fluke calibrators.

You can calibrate your scope with the usual SG503/504, PG506, TG501
and TD pulser arrangement.

Go to Didier's website, and get this manual:

<http://www.ko4bb.com/getsimple/index.php?id=download&file=Tektronix/Tektronix_-_2465B_Oscilloscope/Tek_2465B_2467B_Service_1993.pdf>

-Chuck Harris

leandro.lindemann via Groups.Io wrote:

The service manual states that a Fluke 5820A calibrator is required to calibrate the 2467. This instrument is inaccessible here in Brazil.

I believe that there must be other instruments capable of being used. Can someone tell me what they would be?
 
I intend to rent the instruments I need here in Brazil. I really want to resolve this defect.

Thanks.

Re: 555 Attributes, facets, benefits and General Discussion

Chuck Harris
 

565 is what your are thinking of..

-Chuck Harris

Roy Morgan wrote:

Some decades ago (2 or 3) I had a different dual trace scope but am unsure of the model number. It was the size of the 545 with no separate power unit. It had two vertical channels and time base without any plug-ins as I remember. The bandwidth was modest, meant for medical/physiology use.

It must have been the 502. Maybe I will discover it buried in my long-neglected storage unit.

Roy

Roy Morgan
K1LKY Western Mass

Re: Tektronix 2467B Auto Measure Faulty?

Chuck Harris
 

First thing you need to know is that the cursor measurements are
calibrated to be in the center of the noise on the trace, not on
the peak of the noise on the trace, so all of the 1.06V, or so
measurements you have made with the cursors are not being done
correctly.

There are two principle measurements done with the Parameteric
section: voltage measurements and time measurements.

Voltage measurements use the trigger set point on the hybrid to
measure the most positive voltage of the waveform, and the most
negative voltage of the waveform that they can trigger upon.
They take the difference to get the peak to peak voltage.

Time measurements use the trigger hybrid to trigger the A and B
sweeps to measure the center crossing of the first and second cycle
of the waveform, and then read the time between those two points.

Automatic setup uses all aspects of the measurement system to give
you a 1 cycle, or so, waveform that fits on the screen in amplitude.

The trigger hybrid is the center of both timing and voltage parametric
measurements. It must work for voltage measurements, or it will not
work for either voltage or timing measurements.

But, it can work for voltage measurements, and still not work for
timing.

And, it can work manually for all measurements, and not work at all
for parametric measurements... they use different control paths.

I find that contact problems on the contact pins of the trigger
hybrid socket are the number one problem. You can put in a dozen
new hybrids, but if the socket pin isn't making contact, in just
the right way, none of them will work reliably.

My suspicion is that the pad on one of the hybrid terminals is
done badly, and relies on the socket pin to touch it in just the
right place for it to work. More investigation is necessary.

DeOxit, and some wiping on the socket pins is often helpful.

The Parametric Measurement's PAL's socket is another trouble
area. It should be cleaned with DeOxit.

Now, on to the flowchart:

The first step asks if volts is accurate (must be timing measurement)

This wants you to set the measurement mode to measure volts on an
AC waveform.

If the volts measured is wrong, or simply goofy, then you need to
troubleshoot the trigger system.

If the volts is correctly being measured, then the problem could be
that the parametric measurements section needs to be calibrated.
(CAL01 and CAL09).

In my experience, that rarely, if ever, fixes the
voltage measurement.

-Chuck Harris


leandro.lindemann via Groups.Io wrote:

I'm trying to understand where to start looking for the defect and I really appreciate any help.

Checking the service manual, there is a defect flowchart. In the Parametric measuremet trobleshooting section I have the 1st doubt:

The first first question is:

Is volts Acurate? (Must be timing measurement)

If the answer is no, check triger system
If so, perform cal 01 and cal 09.

My doubt is, is the measure of time that needs to be checked measured by the Auto function or manually?

From the video, you can see that using the Auto option the displayed waveform is outside the time base, but without using the Auto function everything is normal.
Thanks.

Re: 555 Attributes, facets, benefits and General Discussion

Roy Morgan
 

Some decades ago (2 or 3) I had a different dual trace scope but am unsure of the model number. It was the size of the 545 with no separate power unit. It had two vertical channels and time base without any plug-ins as I remember. The bandwidth was modest, meant for medical/physiology use.

It must have been the 502. Maybe I will discover it buried in my long-neglected storage unit.

Roy

Roy Morgan
K1LKY Western Mass

On Feb 26, 2020, at 2:33 AM, Tim Phillips <timexucl@...> wrote:

from Tim P (UK)
re the 555, I've often wondered why the timebases were made plug-in.