Date   

U800 Thermal Images for a 2445 scope

 

After a long calibration session I made some thermal images showing the case temperature of U800. Ambient was 73 degrees F with no moving air other than convection. See pics in photos section.

Regards,
Tom


Re: 7a19 ac coupling

jjgeddes3@netzero.com
 

Could the frequency of the AC signal be too low?

---------- Original Message ----------
From: David DiGiacomo <daviddigiacomo@gmail.com>
To: TekScopes <TekScopes@yahoogroups.com>
Cc: TekScopes2@yahoogroups.com
Subject: Re: [TekScopes] 7a19 ac coupling
Date: Wed, 2 Apr 2014 14:08:56 -0600



On Wed, Apr 2, 2014 at 11:19 AM, jerry massengale <j_massengale@aol.com> wrote:
I just received 2 7a19s for my R7103. Both work on DC but not on AC. Is this a common problem?
I don't think so.

A fix?
Not much to it... seems like it's either the cam switch or C5.



____________________________________________________________
Old School Yearbook Pics
View Class Yearbooks Online Free. Search by School & Year. Look Now!
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Re: 2215 BNC connector source

w2aew
 

It looks like it is the same as the 2215A, Tektronix P/N 131-0126-00. Does anyone have a source (or stash) of these parts?

Thanks,
Alan


Re: 7a19 ac coupling

David DiGiacomo
 

On Wed, Apr 2, 2014 at 11:19 AM, jerry massengale <j_massengale@aol.com> wrote:
I just received 2 7a19s for my R7103. Both work on DC but not on AC. Is this a common problem?
I don't think so.

A fix?
Not much to it... seems like it's either the cam switch or C5.


Re: Tek "Calibration Generator" - what's the modern equivalent

tubesnthings@...
 

Nice - thx, Dave.
Bernd

In a message dated 4/2/2014 11:45:45 A.M. Pacific Daylight Time,
davidwhess@gmail.com writes:




It is not all that complicated. Most function generators can produce at
least
20 volts peak to peak into an open load and 10 volts peak to peak into 50
ohms.
The problem is accurately measuring the output voltage and precisely
generating
low amplitude outputs where amplitude control becomes difficult.

A good multimeter will work for measurements. The RMS AC value of a 2 volt
peak
to peak square wave is 1 volt. The average AC value will be 11.11% higher
so
1.111 volts. When I did this, I checked several different average AC and
RMS
reading voltmeters and got identical results down to the basic specified
accuracy of the meters.

To use the attenuator for generating accurate low level signals, measure
the
attenuation using the voltmeter at a high input signal level so later when
a low
input signal is used, the output will be known. Doing that makes it easy to
accurately generate millivolt and microvolt range signals. Note that you
have
to do this *with* the 50 ohm termination you intend to use because its real
value will be critical.

In general lower frequency square waves should yield more accurate results
than
higher frequency ones although with the AC voltmeters that I used, I found
no
significant differences between 100 Hz and 1 kHz.

On Sat, 22 Mar 2014 23:48:10 -0400, you wrote:

David, Tom, Hank, Gyuri --

Thanks for the very helpful replies.

David, I get the gist of your method and I saw some mentions of it in the
forum archives. Do you happen to have a somewhat detailed procedure or any
tips?

I don’t mind that it takes lots of time, as it’s a learning experience
and I’d rather put time than money into the effort.

Louis

From: David
Sent: Saturday, March 22, 2014 5:16 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Tek "Calibration Generator" - what's the modern
equivalent


I have done the voltage calibration on other oscilloscopes using a
function
generator, an external switched attenuator, and a good voltmeter but
using a
calibration generator is a *lot* faster.

The RMS value of the square wave will be half of the peak to peak value
and an
average responding meter will read 11.1% higher than an RMS responding
meter.
Average responding meters settle faster making them easier to use even
with
having to use a correction factor.

I used the external switched attenuator to get accurate calibrated
outputs at
low voltages. The attenuator itself can be calibrated using the voltmeter
so
the low level output does not need to be measured.

Some function generators will not be able to generate the highest peak to
peak
voltages needed.

On 22 Mar 2014 11:02:07 -0700, you wrote:

I'm carefully reading the Tek 2445 Service Manual in preparation for
calibrating a Tek 2445 that I recently purchased. In "CAL 02 - Vertical", the
manual says to use a "Calibration Generator". I don't have a Tek
"Calibration Generator", so I'm looking for an alternative way of providing the same
signals as a "Calibration Generator"

1. Can I just use a precise voltage source as a substitute for the
"Calibration Generator"?

2. Is the "Calibration Generator" (or its substitute) needed to provide
a precise DC voltage or a precise AC voltage? For example, step 2(e) says
"Connect a 0.5 V, standard-amplitude signal ...". Do they mean 0.5 V
peak-to-peak? Or 0.5 V RMS? Or 0.5 V DC? Or something else? This is not clear from
the instructions.

Since I'll be feeding the signal into the 50 ohm input of the scope, are
there any special considerations with regard to impedance matching of the
signal generator to the 50 ohm input?

Thanks very much for any replies.

Louis


No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4336 / Virus Database: 3722/7231 - Release Date: 03/22/14


earliest use of ICs, DIPPs ?

tubesnthings@...
 

The 3A9/10, relatives of 1A5/7 and forerunners of 5/7A22, are very
late-model diff amp plug-ins for the 560 series and the 561B, in particular. In
addition to the features common to the above half-dozen models, the 3A9 has a
current probe amp and the 3A10 features a strain gage amp. Both have
1000VDC offsets and NO tubes, at all!

Drum-roll: The 3A10's "transducer power supply" is on its own gold-plated
printed circuit board at the lower rear of the chassis and prominently
features an LM741CN in the regulator circuit!
The board's art is dated 1 9 6 9!

Any contenders for 1st IC/DIPP in Tek gear?
Bernd Schroder


Re: Tek "Calibration Generator" - what's the modern equivalent

 

It is not all that complicated. Most function generators can produce at least
20 volts peak to peak into an open load and 10 volts peak to peak into 50 ohms.
The problem is accurately measuring the output voltage and precisely generating
low amplitude outputs where amplitude control becomes difficult.

A good multimeter will work for measurements. The RMS AC value of a 2 volt peak
to peak square wave is 1 volt. The average AC value will be 11.11% higher so
1.111 volts. When I did this, I checked several different average AC and RMS
reading voltmeters and got identical results down to the basic specified
accuracy of the meters.

To use the attenuator for generating accurate low level signals, measure the
attenuation using the voltmeter at a high input signal level so later when a low
input signal is used, the output will be known. Doing that makes it easy to
accurately generate millivolt and microvolt range signals. Note that you have
to do this *with* the 50 ohm termination you intend to use because its real
value will be critical.

In general lower frequency square waves should yield more accurate results than
higher frequency ones although with the AC voltmeters that I used, I found no
significant differences between 100 Hz and 1 kHz.

On Sat, 22 Mar 2014 23:48:10 -0400, you wrote:

David, Tom, Hank, Gyuri --

Thanks for the very helpful replies.

David, I get the gist of your method and I saw some mentions of it in the forum archives. Do you happen to have a somewhat detailed procedure or any tips?

I don’t mind that it takes lots of time, as it’s a learning experience and I’d rather put time than money into the effort.

Louis

From: David
Sent: Saturday, March 22, 2014 5:16 PM
To: TekScopes@yahoogroups.com
Subject: Re: [TekScopes] Tek "Calibration Generator" - what's the modern equivalent


I have done the voltage calibration on other oscilloscopes using a function
generator, an external switched attenuator, and a good voltmeter but using a
calibration generator is a *lot* faster.

The RMS value of the square wave will be half of the peak to peak value and an
average responding meter will read 11.1% higher than an RMS responding meter.
Average responding meters settle faster making them easier to use even with
having to use a correction factor.

I used the external switched attenuator to get accurate calibrated outputs at
low voltages. The attenuator itself can be calibrated using the voltmeter so
the low level output does not need to be measured.

Some function generators will not be able to generate the highest peak to peak
voltages needed.

On 22 Mar 2014 11:02:07 -0700, you wrote:

I'm carefully reading the Tek 2445 Service Manual in preparation for calibrating a Tek 2445 that I recently purchased. In "CAL 02 - Vertical", the manual says to use a "Calibration Generator". I don't have a Tek "Calibration Generator", so I'm looking for an alternative way of providing the same signals as a "Calibration Generator"

1. Can I just use a precise voltage source as a substitute for the "Calibration Generator"?

2. Is the "Calibration Generator" (or its substitute) needed to provide a precise DC voltage or a precise AC voltage? For example, step 2(e) says "Connect a 0.5 V, standard-amplitude signal ...". Do they mean 0.5 V peak-to-peak? Or 0.5 V RMS? Or 0.5 V DC? Or something else? This is not clear from the instructions.

Since I'll be feeding the signal into the 50 ohm input of the scope, are there any special considerations with regard to impedance matching of the signal generator to the 50 ohm input?

Thanks very much for any replies.

Louis


No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4336 / Virus Database: 3722/7231 - Release Date: 03/22/14


Re: 2430 battery leak

 

Starting with the most damaged areas and the most damaged ICs, I would remove
the ICs, closely inspect and clean with a toothbrush and water, and then install
open frame sockets or just machined collet socket pins by themselves which would
allow more exposure and are lower profile.

If that does not resolve anything, then I would replace ICs starting from the
battery backed up SRAM and moving outward.

If your Hakko 808 works as well as my Weller DS227, then it should make IC
removal into a trivial exercise.

On 01 Apr 2014 07:56:25 -0700, you wrote:

Ugh, so after running the CPU in the "kernel" mode I'm no nearer. What I do know is this:
- On reset the GPIB LEDs are all lit, then the first one goes out.
I haven't seen the others change at all so far.
- She seems to get a little further along when she's cold.
- Sometimes she gets as far as to blink the trigger lights.
When this happens she seems to blink a 3 code.
- The address decoding all looks sane.
- There are no stuck address or data lines.
- She doesn't get far enough to enable the front panel processor.
- The CPU does get periodic interrupts, and it does successfully acknowledge them (which is just some address decoding).

I'm a little stumped as to how I'd debug this further with the equipment I have (a DMM and a 2467 scope). It stands to reason that this might be a marginal data bus buffer, or - say - a register that occasionally pulls on the data bus.
I noticed that there's "fuzz" on the 5VD rail when the address bus cycles through the address range where the IO registers sit. This could be due to fighting data buffers, or it might simply be because there's higher consumption there than in e.g. the SRAM/ROM ranges.
Alternatively this might be because the system RAM chip is shot...

Does anyone here have advice for how to proceed? I have a Hakko 808 at hand, so I can relatively easily suck out chips, if it comes to that...


7a19 ac coupling

 

Hi,

I just received 2 7a19s for my R7103. Both work on DC but not on AC. Is this a common problem? A fix?

Jerry Massengale


Re: 556 Option CT

tubesnthings@aol.com <tubesnthings@...>
 

Nice, Cliff!
Am lucky to know which day of the week, never mind month it is…
Sure didn't see this coming.
B

Sent from my Verizon Wireless Droid

-----Original message-----
From: Cliff White <cn.white@sunbelt-plb.com>
To: TekScopes@yahoogroups.com
Sent: Wed, Apr 2, 2014 15:40:29 GMT+00:00
Subject: Re: [TekScopes] 556 Option CT

Yep, Dan is right. Sorry Bernd...

Although a counter/timer would be a cool option. :)

Respectfully,
Cliff White, W5CNW
w5cnw@arrl.net <mailto:w5cnw@arrl.net>
On 04/02/2014 07:16 AM, Daniel Koller wrote:

Yeah, you got us!! Note what day it was when Cliff posted.

Dan

On Tuesday, April 1, 2014 10:33 PM, "matt8@hotmail.de"
<matt8@hotmail.de> wrote:


https://groups.yahoo.com/neo/groups/TekScopes/photos/albums/1161693399/lightbox/?mode=tnℴ=ordinal&start=1&dir=asc
https://groups.yahoo.com/neo/groups/TekScopes/photos/albums/1161693399/lightbox/?mode=tnℴ=ordinal&start=1&dir=asc

haha

Best regards
Matt

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]



[Non-text portions of this message have been removed]


Re: 556 Option CT

Cliff White
 

Yep, Dan is right. Sorry Bernd...

Although a counter/timer would be a cool option. :)

Respectfully,
Cliff White, W5CNW
w5cnw@arrl.net <mailto:w5cnw@arrl.net>
On 04/02/2014 07:16 AM, Daniel Koller wrote:

Yeah, you got us!! Note what day it was when Cliff posted.

Dan

On Tuesday, April 1, 2014 10:33 PM, "matt8@hotmail.de"
<matt8@hotmail.de> wrote:


https://groups.yahoo.com/neo/groups/TekScopes/photos/albums/1161693399/lightbox/?mode=tnℴ=ordinal&start=1&dir=asc
https://groups.yahoo.com/neo/groups/TekScopes/photos/albums/1161693399/lightbox/?mode=tnℴ=ordinal&start=1&dir=asc

haha

Best regards
Matt










[Non-text portions of this message have been removed]


Re: [hp_agilent_equipment] 3253A ANALOG STIMULUS/RESPONSE UNIT

Daniel Koller
 

Howdy.  

  Has anybody ever used one of these things?  And what for?  

  Years ago (~30) I picked up a huge, old, vacuum tube based "stimulus response" system made by some British company that came in a big 19" rack.  It was of the vacuum tube-on-pc board vintage, so perhaps early-mid 1960's.  It was painted blue with white lettering and had all metric fasteners that stripped apart as I tried to disassemble the unit.  It was useless to me so I stripped it completely for parts.  One of the most interesting parts on it was a 3" CRT which I saved and integrated into a homemade X-Y oscilloscope, keeping the existing circuit boards for the HV supply and the x and y drivers.  I added solid state input sections to run the drivers and then integrated my x-y scope into a homemade lightning detector which I described before and hence the cross-posting.   This is one of the instruments that inspired my earlier post on "non standard uses of a CRT".

   But I've always liked the strange white-lettering-on-Navy-Blue scheme that the original equipment used.    So, the stimulus was the instrument itself and the response a lifelong interest in electronics!   But I would still like to know what one does with one of these things.  I am thinking it's largely for medical/biological research.  In physics or electronics or other hard sciences you typically know what you are looking for so you don't just apply a stimulus and look for some "response".  More typically you tailor a specific experiment and look for something specific.

Dan

On Wednesday, April 2, 2014 8:37 AM, Dr. David Kirkby <drkirkby@gmail.com> wrote:

 

On 2 Apr 2014 09:28, <poldhu1901@aol.com> wrote:
Hi Tom
 
I asked for information on this unit sometime in 2009 and received several helpful replies that enabled me to identify its original purpose, an archive search will find them if you haven't tried that already, but was still no nearer to finding much use for it.
Maybe someone would consider sponsoring a competition for the best use of one! If the prize money was high enough, the value of the units would rise as people try to buy them.
Maybe there's a business opportunity there!
Dave.



[Non-text portions of this message have been removed]


Re: 2430 battery leak

Siggi
 

I traced through the address and data busses again, and looked closely at the power supply wiggle again. Turns out the wiggle coincides with the 500Hz timer interrupt getting to the main CPU. As the address lines run through the IO range of addresses, they'll incidentally reset the timer interrupt flip-flop, and when it clocks high again I get a ~100mV wiggle on the power supply.
I suspect this is just business as usual, though I believe the CPU ought to have the interrupt masked.
I'm just as stumped as I was before...

Next up I suppose I'll try to replace the main RAM chip, see what happens.


Re: 556 Option CT

Daniel Koller
 

Yeah, you got us!!  Note what day it was when Cliff posted.

  Dan


Re: 556 Option CT

mattko87
 


Re: 7854 ROM, again ..

Mark Huffstutter
 

Sorry, that was supposed to be a PM....

Mark


Hello,
Could You give me an idea of shipping to Seattle, WA?
specifically
the 98115 area code.

Thank
You,
Mark

RE:

The 7854 and ROM issue. I have no more time or
interest in this
instrument. I installed the
Penti ROM set and
wiring per Dave, and it will
now get past the ROM failure,
apparently, and stall on the RTC
test
failure, and not get past
that.
So, before I put this non-functional 7854 up on Ebay,
probably parted out,
I am offering it complete with
the
waverform calculator to the Group. S/N
is
B010126, no plugins,
very little apparent use, the CRT HV lead
has
virtually no
black dust accumulated on it. A
little surface dirt from
years
of storage
though. Comes with the Penti ROM installed and the
original MOSTEK set as well. Looking for $150 + shipping. PM for a
shipping quote.

[Non-text
portions of this
message have been removed]



[Non-text portions
of this message have been removed]


Re: 7854 ROM, again ..

Mark Huffstutter
 

Hello,
          
Could You give me an idea of shipping to Seattle, WA?
specifically
the 98115 area code.

Thank You,
Mark

RE:

The 7854 and ROM issue. I have no more time or
interest in this
instrument. I installed the Penti ROM set and
wiring per Dave, and it will
now get past the ROM failure,
apparently, and stall on the RTC test
failure, and not get past
that.
So, before I put this non-functional 7854 up on Ebay,
probably parted out,
I am offering it complete with the
waverform calculator to the Group. S/N
is B010126, no plugins,
very little apparent use, the CRT HV lead has
virtually no
black dust accumulated on it. A little surface dirt from
years
of storage though. Comes with the Penti ROM installed and the
original MOSTEK set as well. Looking for $150 + shipping. PM for a
shipping quote.

[Non-text portions of this
message have been removed]



[Non-text portions of this message have been removed]


Re: 7854 ROM, again ..

testtech@...
 

RE:

The 7854 and ROM issue. I have no more time or interest in this instrument. I installed the Penti ROM set and wiring per Dave, and it will now get past the ROM failure, apparently, and stall on the RTC test failure, and not get past that.
So, before I put this non-functional 7854 up on Ebay, probably parted out, I am offering it complete with the waverform calculator to the Group. S/N is B010126, no plugins, very little apparent use, the CRT HV lead has virtually no black dust accumulated on it. A little surface dirt from years of storage though. Comes with the Penti ROM installed and the original MOSTEK set as well. Looking for $150 + shipping. PM for a shipping quote.


Re: 556 Option CT

tubesnthings@aol.com <tubesnthings@...>
 

Please send pics of the 556 mod CT, Cliff!!
Faceplate AND associated circuit boards, etc.

Never heard of anything like it in the 500 series - except 567/568.
On "new" scopes, such as the 2245A and many others, these kinds of functions
are implemented via z-axis modulation by way of "delayed time base" controls
used for markers. The 567/6R1 & 568/230? were the first instruments to
feature a similar approach, which required a LOT of chassis space plus power
supplies. No way to squeeze anything like that into the already dense 556!
Is this a later aftermarket mod based on ICs?

Do tell!
Bernd Schroder

Sent from my Verizon Wireless Droid

-----Original message-----
From: Cliff White <cn.white@sunbelt-plb.com>
To: TekScopes@yahoogroups.com
Sent: Tue, Apr 1, 2014 15:49:10 GMT+00:00
Subject: [TekScopes] 556 Option CT

I have a 556 with Opt CT stamped on it.

There is also another set of controls across the top that look like a
counter/timer. In the little bit of usage I've given it, there has been
a readout on the crt giving counter/timer type parameters of the signal.

Anyone ever seen anything like this?

--
Respectfully,
Cliff White, W5CNW
w5cnw@arrl.net <mailto:w5cnw@arrl.net>


Re: 2215 BNC connector source

w2aew
 

The connector in question is Tektronix part number: 131-0126-00

Alan

87061 - 87080 of 192827