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Re: Tektronix 453 Power Indicator Bulb needed

 

Sphere says they have 3 new in stock

T1 Based Lamp 150-0045-00 Incandescent Lamp T-1 miniature lamp with base. New in factory bags. 3 New $5.00

On Mon, Jun 18, 2018 at 09:31 am, Michael Gladu wrote:


I am looking for one B1107, 'Power On' indicator bulb, for the Tektronix 453
that I am trying to fix.
The Tek part number is 150-0045-00.
Does anyone have one that they would like to sell me or can anybody suggest a
place
to buy a replacement? The bulb appears to be a custom built bulb and may be
pure
un-obtainium. :(

Thanks.

73 de N1FBZ


Re: FS: Tektronix scopes on craigslist; North of Boston, MA

 

I picked up a 7844 from this seller last week. He's a nice guy and clearing
out a scope rehab hobby, apparently.

--
Phil


On Fri, Jun 15, 2018 at 1:26 AM Craig Sawyers <c.sawyers@...>
wrote:

$100 for a 067-0587-02 calibration plug in is a steal.

Craig

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Shannon Hill
Sent: 14 June 2018 19:33
To: [email protected]
Subject: [TekScopes] FS: Tektronix scopes on craigslist; North of
Boston, MA

Search for xyzzy in the listing body.
Thinning the herd, several working scopes for $100; along with some HP
and GenRad gear.






Problematic Tek 7A26 Vertical Amp

 

I have a 7A26 vertical amp unit that is misbehaving. It is housed in a Tek 7704A. A borrowed (good) 7A26 operates correctly. The symptoms are as follows:

(1) The amplitude of a given signal does not remain constant when trace is scrolled from top to bottom on CRT.
(2) Both channels behave as described here.
(3) Occurs with low frequency traces (10 KHz) AND high frequency traces (10 MHz).
(4) A signal that shows 3 div is positioned with the upper peaks at the topmost graticule line.
(5) Its position is lowered using the POSITION pot to the next lowest graticule line and still shows 3 div.
(6) Its position is lowered using the POSITION pot to the next lowest graticule line it shows 2.6 div.
(7) Its position is lowered using the POSITION pot to the next lowest graticule line it shows 3 div.
(8) Its position is lowered using the POSITION pot to the next lowest graticule line it shows 3 div.
(9) Its position is lowered using the POSITION pot to the next lowest graticule line it shows 3 div.

The rapid motion sequence of the positioning is that the trace size diminishes in the upper portion (at approximately the second graticule line down) briefly and then regains its amplitude.

The pictures of this sequence can be seen at the following URL:



Any suggestions on where to begin searching for this problem are greatly appreciated.
--
William, k6whp
"A friend told me to cheer up, things could be worse.
So I cheered up and, sure enough, things got worse!"


Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)

 

Hi Menahem:
I should place the illinois capacitor link for comparison to the Nichicon .

You'll see for the 50V, 2200uF cap I am using the KXM series (which I use mainly now) has much better ripple specs than Nichicon.
--------------------Capacitor size is 18mm x 35.5mm-----------------

illnois Capacitor: 3690 mA RMS ripple


Nichicon PW: 3100 mA RMS ripple.


Re: using scope channel 1 and channel 2 invert and add functions vs floating DUT

 

Thanks for the comment Steve ! I look forward to that document posting.


Good point on the common mode resolution limitation.

A question in regard to the CMRR, is the poor response a function of the scope speed and was it predictable? Would I be able to determine a max frequency just based on scope speed?

NielsenTelecom

On Thu, Jun 7, 2018 at 03:09 pm, ditter2 wrote:


Shortly before leaving Tektronix, I wrote a good app note on making floating
measurements, related to SMPS. That was 20 years ago, I don't think Tek still
has it on the web site. I will try to find the original file and post it. We
made several real measurements in the lab for research in the paper. Floating
instruments, isolators, and differential measurement techniques were compared.
Without rehashing the entire note, a summary is that for most applications,
differential measurements give the best results.
Subtracting channels is a differential mode of operating the scope. Compared
with a true differential amplifier or probe, channel A minus channel B has
much poorer CMRR at higher frequencies. The other major limitation is common
mode range. The common mode is the voltage you are floating on. IT is
limited to the full scale of the scope at the V/DIV setting you are using.
This is a real limitation in SMPS work when you need to measure small voltages
riding on top o flarge voltages. The common example in higher power inverters
is measuring the upper gate drive in a push-pull drive stage. The upper gate
only has a few volt (15 maximum) swing riding on a 350V swing. To keep the
common mode (350 V swing) within the common mode range, you need to set both
channels to 50 V/div. IT is difficult to see the gate drive with a 5 to 15 V
swing with the scope set to 50 V/div.

Steve


Re: using scope channel 1 and channel 2 invert and add functions vs floating DUT

 

Thanks Dennis, I just downloaded it. I'll look at it.

Thanks for the comment.


Tektronix 453 Power Indicator Bulb needed

Michael Gladu
 

I am looking for one B1107, 'Power On' indicator bulb, for the Tektronix 453 that I am trying to fix.
The Tek part number is 150-0045-00.
Does anyone have one that they would like to sell me or can anybody suggest a place
to buy a replacement? The bulb appears to be a custom built bulb and may be pure
un-obtainium. :(

Thanks.

73 de N1FBZ


Tek 49x -- Power Supply Replacement Capacitor List

 

Has someone compiled a list of the capacitors to replace in a Tek 49x series power supply? I seem to remember seeing such a parts list in the past, but do not readily see how to search the archives for the topic.

Bruce, KG6OJI


Re: 465 bad rise time

 

Im using a 50ohm cable a 50ohm through termination and a pg506 fast rise pulse.

On Mon, Jun 18, 2018 at 08:31 am, HankC, Boston, WA1HOS wrote:


What is the source of the signal being displayed ?
What kind of probe is being used ?Is it compensated ??Is the probe ground lead
connected ?
Do yourself a favor & lose the probe.Connect to a decent signal source, via
coax, using a 50 ohm termination at the scope end.

HankC, Boston


Re: 465 bad rise time

 

What is the source of the signal being displayed ?
What kind of probe is being used ?Is it compensated ??Is the probe ground lead connected ?
Do yourself a favor & lose the probe.Connect to a decent signal source, via coax, using a 50 ohm termination at the scope end.

HankC, Boston


Re: Up to date capacitor list for Tek 2465A and 2465B scopes (2018)

Jeff Davis
 

Hi Ron,


I wonder if we may know each other. I knew a Ron who would be about your age who ran an engineering organization in Cedar Rapids. At the time, I was a brash young engineering group manager in a different organization who thought he knew it all. Life has a way of humbling one.


Now I live in Southern California and fix up Tak scopes for fun and occasionally resell them. Still working, but probably not too much longer.


Regards,

Jeff

You may address me as Ron, or Mac (for machineguy). I usually use Mac on the net and Ron in the "real world". >As a brief introduction, I am 78 years old, retired electronics engineer, now hobbyist, living in Iowa, USA.


Re: 465 bad rise time

 

Sorry Raymond, again I missed you message of a few minutes ago!
BTW I sold my one and only 465 some time ago, so I can't help with doing measurements.
Albert


Re: 465 bad rise time

 

They share the same output amplifier.


Seeing that are both channels are essentially the same just seems weird to me.


Re: 465 bad rise time

 

On Mon, Jun 18, 2018 at 05:06 am, lop pol wrote:


Seeing that are both channels are essentially the same just seems weird to me.
The vertical output Amp and some other parts, like parts of the channel switch, are common.

Raymond


Re: Self Governance of TekScopes.

 

In the end, it is the moderator's responsibility to determine how he or she wished to have the list moderated. I this case, Dennis has laid out how he wishes the list to be moderated.

DaveD

On 6/18/2018 5:52 AM, JJ wrote:
I would think that it's the moderator's responsibility and no one else
(elders or otherwise) to filter the various threads. There are certain
topics that are completely off topic like politics and should be cutoff.
But, there are others that are technical and very informative which are
gleaned from years of experience that allow us to pick up information that
is very helpful. I welcome those. So, you need to have a jeweler's eye!

John Justin

On Mon, Jun 18, 2018 at 1:17 AM, Jeff Urban <JURB6006@...> wrote:

Bit odd you bring this up now when I just got through posting in a thread
about 2 sided boards, and that went into some other things. My experience,
someone else about car radios using the same manufacturing methods and all,
one with their own stereo unit the fixed by fixing a 2 sided board.

Now there's some thread drift forya, but it is still pertinent to the
subject. Of course WW2 is not. I have a group and I was thinking what I
would do. I would probably get in there and say "this one can slide, but
anymore of this political shit and we are talking action, I do not want it
here". And that it makes enemies easier than it makes friends.

But now there is the Fluke 3300 thread. That is not a Tek scope. I have
no problem with it, I think maybe they could have been spurred on to my
group but there are not enough members now to be sure to get anything good
back. If that is close enough to on topic fine. Good that you don't want to
stifle.

I think the thing here is that in moderating these, you can't just grind a
line into concrete. That's why we have human moderators. (and judges and
whatever)

You could send some to my group, which I made specifically for other test
equipment. But I don't want anyone forced. I don't want to force anyone to
do anything. Not the WW2 thing though.

Put it this way, I may respond in threads that go political, but I will
never start one. I have more respect than that.




Re: 465 bad rise time

 

On Mon, Jun 18, 2018 at 04:41 am, Raymond Domp Frank wrote:


On Mon, Jun 18, 2018 at 04:23 am, lop pol wrote:


I will start turning screws. I just wanted to get opinions on whether this
could possibly be a problem with a bad component prior to messing with the
calibration.
Before you start turning screws:

1. It is not uncommon for the variable caps to become open. I've had that
happen to some in the vertical (output) amplifier. I've seen both the rotor
not moving *and* the connection to the stator opening up. When screwing, check
those first by watching their influence.

2. Look at the flatness of the square wave at lower frequencies (1 kHz, 10 kHz
and up). I've seen an increase of the impedance in the differential circuits
out of the delay line causing huge distortions, not just slow edges, by
high-drifting low-value R's.

Now that I've become involved, I have to ask a stupid(?) question: You *are*
using the right i.e. fast edges of the PG506, are you? The left-hand BNC has a
fast *fall* time, the middle BNC has a fast *rise* time.

Raymond
Yes I'm using the correct output. The rise time reminded me of my 7a26 that had bad var capacitors, but that only affected one channel. Seeing that are both channels are essentially the same just seems weird to me.


Re: 465 bad rise time

 

You have the proper fast rise generator to perform an adjustment. The risk in my opinion is that you destroy a stuck trimcap or trimpot.
You might first verify DC levels in the output amplifier stages and perhaps symmetry in the push-pull signals. Often some stages are common-base current driven which makes it more difficult to check signals.
Unlike some other manuals the 465 manuals do not tell which part of the curve is affected by each adjustment.
Which version output amplifier is in your 465, discrete or IC? It seems you use the pre-B250000 manual because of what you said about the 10X magnifier. The B250000-up manual clearly mentions the 10X mag. That manual also shows both versions output amplifier.

On Mon, Jun 18, 2018 at 04:23 am, lop pol wrote:


On Mon, Jun 18, 2018 at 12:34 am, Albert Otten wrote:


With curves like this
/g/TekScopes/photo/59361/1?p=Name,,,20,1,0,0 I wouldn't
even bother to calculate a rise time. Obviously the main problem is roll-off. I
would search the manual for Adjustments which influence that nanoseconds
part of the curve and try these first.
Ok. I will start turning screws. I just wanted to get opinions on whether this
could possibly be a problem with a bad component prior to messing with the
calibration. I would hate to have a bad transistor or capacitor causing the
bad rise time and start turning the adjustments and mess up something that was
actually already set correctly.


Re: Self Governance of TekScopes.

 

I would think that it's the moderator's responsibility and no one else
(elders or otherwise) to filter the various threads. There are certain
topics that are completely off topic like politics and should be cutoff.
But, there are others that are technical and very informative which are
gleaned from years of experience that allow us to pick up information that
is very helpful. I welcome those. So, you need to have a jeweler's eye!

John Justin

On Mon, Jun 18, 2018 at 1:17 AM, Jeff Urban <JURB6006@...> wrote:

Bit odd you bring this up now when I just got through posting in a thread
about 2 sided boards, and that went into some other things. My experience,
someone else about car radios using the same manufacturing methods and all,
one with their own stereo unit the fixed by fixing a 2 sided board.

Now there's some thread drift forya, but it is still pertinent to the
subject. Of course WW2 is not. I have a group and I was thinking what I
would do. I would probably get in there and say "this one can slide, but
anymore of this political shit and we are talking action, I do not want it
here". And that it makes enemies easier than it makes friends.

But now there is the Fluke 3300 thread. That is not a Tek scope. I have
no problem with it, I think maybe they could have been spurred on to my
group but there are not enough members now to be sure to get anything good
back. If that is close enough to on topic fine. Good that you don't want to
stifle.

I think the thing here is that in moderating these, you can't just grind a
line into concrete. That's why we have human moderators. (and judges and
whatever)

You could send some to my group, which I made specifically for other test
equipment. But I don't want anyone forced. I don't want to force anyone to
do anything. Not the WW2 thing though.

Put it this way, I may respond in threads that go political, but I will
never start one. I have more respect than that.




Re: 465 bad rise time

 

On Mon, Jun 18, 2018 at 04:23 am, lop pol wrote:


I will start turning screws. I just wanted to get opinions on whether this
could possibly be a problem with a bad component prior to messing with the
calibration.
Before you start turning screws:

1. It is not uncommon for the variable caps to become open. I've had that happen to some in the vertical (output) amplifier. I've seen both the rotor not moving *and* the connection to the stator opening up. When screwing, check those first by watching their influence.

2. Look at the flatness of the square wave at lower frequencies (1 kHz, 10 kHz and up). I've seen an increase of the impedance in the differential circuits out of the delay line causing huge distortions, not just slow edges, by high-drifting low-value R's.

Now that I've become involved, I have to ask a stupid(?) question: You *are* using the right i.e. fast edges of the PG506, are you? The left-hand BNC has a fast *fall* time, the middle BNC has a fast *rise* time.

Raymond


Re: 465 bad rise time

 

Is the bandwidth limit turned on ( maybe a fault with the switching? )
The BW limit switch is off. Turning it on increases the rise time and smoothed the trace like I would expect.

Do you have any other scope with a higher bandwidth available? Some way to
verify the setup.
Yes but i checked the setup with my 468 (100 mhz) and the rise time was the correct 3.5ns


On Mon, Jun 18, 2018 at 12:34 am, Albert Otten wrote:


With curves like this
/g/TekScopes/photo/59361/1?p=Name,,,20,1,0,0 I wouldn't even
bother to calculate a rise time. Obviously the main problem is roll-off. I
would search the manual for Adjustments which influence that nanoseconds part
of the curve and try these first.
Ok. I will start turning screws. I just wanted to get opinions on whether this could possibly be a problem with a bad component prior to messing with the calibration. I would hate to have a bad transistor or capacitor causing the bad rise time and start turning the adjustments and mess up something that was actually already set correctly.



So BW = 0.35/risetime in seconds or 0.35/0.000000006 = ~~60 MHz.
The 465 should go around 100 MHz bandwidth. Around 3.5 ns.
.







----- Original Message -----
From: "lop pol via Groups.Io" <the_infinite_penguin@...>
To: <[email protected]>
Sent: Monday, June 18, 2018 12:22 AM
Subject: Re: [TekScopes] 465 bad rise time


Time div is set to .05us but I have 10x mag on so that should be 5ns.

On Sun, Jun 17, 2018 at 09:10 pm, tmillermdems wrote:


Ok, it looked like a probe at first. What is the H sweep rate set to?
Can't
see it in the pictures.

Looks like 1 1/4 divisions on the horizontal 10-90% points.

Regards


----- Original Message -----
From: "lop pol via Groups.Io" <the_infinite_penguin@...>
To: <[email protected]>
Sent: Monday, June 18, 2018 12:02 AM
Subject: Re: [TekScopes] 465 bad rise time


Im using a 50ohm cable with a 50ohm through terminator.

/g/TekScopes/photo/59361/2?p=Name,,,20,1,0,0



On Sun, Jun 17, 2018 at 08:50 pm, tmillermdems wrote:


You are looking at the waveform with a scope probe that presents a 10
meg
ohm load to the pulse generator. What you need to do is use a 50 ohm
cable
to go from the generator to the scope input and include a 50 ohm through
termination right at the scope. A real simple solution would be to use a
BNC
T with the center loaded with a 49.9 ohm resistor. Or just look for a 50
ohm
through termination on ebay.

Regards




----- Original Message -----
From: "lop pol via Groups.Io" <the_infinite_penguin@...>
To: <[email protected]>
Sent: Sunday, June 17, 2018 9:47 PM
Subject: [TekScopes] 465 bad rise time


Hey guys. I have done a lot of work to this 465. I had initially planned
on
selling it to help me buy some plugins for my 7633. I decided I don't
want
to sell it and am keeping it. Today I checked its rise time with a pg506
fast rise. Both channel 1 and 2 closely resemble each other and they are
not
close to right. Before I start trying to calibrate this thing, does it
look
like there is some type of component issue left to fix? I am thinking
since
both channels are so alike there is something wrong besides just out of
calibration. Thanks guys.

here are some pictures

/g/TekScopes/photo/59361/0?p=Name,,,20,1,0,0

/g/TekScopes/photo/59361/1?p=Name,,,20,1,0,0