Date   

Re: "liquid crystal driver" sighting

Glenn Little
 

On 12/10/2019 10:28 PM, Glenn Little WB4UIV wrote:
I will try and get hi res pix posted this weekend.
Hope to have schematic drawn early next year.
This appears to fit a TM-500 series frame.
The unit appears to have two channels.
The main board id very good quality.
There are two "proto" type boards in the unit.
One is for fuses.
The other has a pair of 74121 ics on it.
When I got it the edge card connector was damaged, thankfully if a place where there are no used pins.
There was one power transistor missing and I can replace it with one like in the other channel.
There is also a ground binding post missing, this is easily replaced.
The pictures will be of the unit as I received it.
This has controls for PW UPPER and PW LOWER for both channels.
There is also a DELAY and AMPLITUDE control for each channel.
There is a BNC for the top channel only INPUT.
There is a BNC for SYNC.
The SYNC appears to go to both channels.
There is a label on the front REL 11, so, maybe there are others out there.
The front binding posts are UPPER OUTPUT, LOWER OUTPUT and GROUND for each channel.
The active backplane pins are 2A, 3A, 6A, 7A, 8A, 9A, 10A, 12A, and 7B.
8B, 11B and 8A are connected.
12A and 12B are connected together.
All of these pins are power related, so the only inputs and outputs are via the front panel.
There is a keyway between pins 6 and 7.
There are "flying" jumpers between some IC pins with some of these pins lifted from the sockets.
Probably still a work in progress.
The front panel is thin aluminum with, what looks like, photo etching for the labeling and shading.
Harmonica connectors are used to connect to the board.

More to follow
Glenn



On 12/10/2019 12:50 PM, p mc wrote:
(seeing this a few weeks later)

Glenn,

Like DaveD says, lots of people here can help with TekWiki. Or you can ask  kurt.harlem@gmail.com for a TekWiki account if you want to get into that yourself.

Back in October I made a stub page with  crops from the pictures from the eBay listing:
http://w140.com/tekwiki/wiki/Liquid_Crystal_Driver

A first question might be what type of mainframe the plugin plugs into. If you haven't already sussed that, a picture of the edge connector cut-outs will help.

Curious to see what you've got...





--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@arrl.net AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"


Re: 465M Junker

toby@...
 

On 2019-12-27 4:23 PM, kb6nax wrote:
Progress report on the 465M junker:  After a couple of good sessions I
think I found nearly all of the problems. ...
Thanks for the informative update! I love a happy ending.

*Stares at the 466 waiting for attention...*

--Toby



Arden



Re: Tektronix 2465

Jose Alfredo
 

Hey Reg, those gadgets would fit my needs. I'll buy  those two from Leo Bodnar.




Problem is I spent this hole afternoon trying to enter the Cal routines. Turned off the scope, changed the Cal/NoCal jumper to the Cal position. Checked twice for the correct position and turned on the scope. Pressing both cursors type buttoms and the slope one caused the scope to enter in the Cal Menu. But moving trigger coupling switch up and releasing it caused the scope to give 00 option and the messege that it passed all tests. It just don't go to the Cal 01 routine.




Any help?




--


José Alfredo C. Santos

On Fri, Dec 27, 2019 at 6:31 PM -0300, "Reginald Beardsley via Groups.Io" <pulaskite=yahoo.com@groups.io> wrote:










Jose,

You didn't state a budget. The lowest cost and actually very good option is to buy an ADF4351 based VFO with simple interface such as:

https://www.ebay.com/itm/US-35-4000MHz-RF-Signal-Simple-Generator-Signal-Source-ADF4351-VFO-HXY-D6-V1-02/202853156592

It's entirely adequate and in a nice case, a very useful piece of T&M kit.

If you want really top notch quality calibration references, I'd like to suggest getting the following two items:

http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=124&products_id=295

http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301

Those will meet your immediate need and also provide metrology grade references for rise time and frequency for many years to come.

Have Fun!
Reg


2465 Displays Channel Input Traces in Top Right Quadrant Only

12ax7
 

My Craigslist 2465 deal initially worked ok except for very blurry traces and alphanumerics. So, a re-capping and calibration project was in order. When I opened the case to look at the PSU, one of the boards had several caps that had very clearly spewed their contents. Rather than try to use caps I had on hand I felt it would was better to source the caps from someone who had done this before. It was the right decision since the process went relatively smoothly even though it took a little longer than expected.

After recapping, the alphanumerics and traces are now very clear … very happy with that.

However, I now get TEST 05 FAIL 44 on boot up. After I push A/B the test message disappears, and all the channel traces display in the top right quadrant of the screen.

What’s strange is that both the reference and delta cursors display properly, extending from the top of the screen to the bottom. The alphanumerics display clearly at the top and bottom of the screen, across the screen as expected.

In the top right quadrant I see the traces - 3 of them only. The bottom trace is a little thicker than the other 2 leading me to believe that channel 1 and channel 2 are superimposed over each other.

I can vertically move channel 3 and channel 4 within the upper right quadrant.

I can connect a test signal to channel 3 or 4 and see the "squashed" trace ... in the upper right quadrant only.

No test signals work when connected to channel 1 or channel 2.

The fan is also caput; a replacement is on order.

I know I’m going to have to re-calibrate the 2465, but want to see if calibration is the cause of the upper right quadrant display problem, or is something else amiss.

I’m scratching my head over the block diagram and schematics trying to figure out where to start and what to dive into.
Any guidance on this would be greatly appreciated.

Thanks,
Jeff


Re: tektronix 7S14 batteries and time base question

John Gord
 

It might be possible to include a LM385 1.2v shunt regulator. They work down to 10uA and provide a lower dynamic impedance. They are supposed to tolerate shunt capacitance well.
--John Gord

On Fri, Dec 27, 2019 at 04:03 PM, Bruce Griffiths wrote:


For greatest photocurrent in the detector LED, first choose the detector LED
for 1.3V and then choose the emitter so that its peak emission is around 50nm
shorter in wavelength than the emission from the LED chosen as a detector.
Measuring the detector LED photocurrent is essential, even better measure the
detector LEDs slope resistance when biased by the photocurrent.

Bruce
On 28 December 2019 at 12:51 "Carl Hallberg via Groups.Io"
<n9ess=yahoo.com@groups.io> wrote:


Hi Bruce,
Then tell us what color driver to use with what color receiver to get approx
1.3V
Carl






On Friday, December 27, 2019, 5:46:43 PM CST, Bruce Griffiths
<bruce.griffiths@xtra.co.nz> wrote:





The peak response of a LED acting as a photodiode occurs at a shorter
wavelength than its peak emission.
Thus using a pair of red (or green, or blue etc) LEDs isn't the most
effective combination.
I have an LTspice simulation that indicates that higher photocurrents are
better in this application as the settling time to the sampling transients is
reduced.
Since the minority carrier lifetime is typically in the range of 3-120ns for
visible LEDs they tend to act as resistors (value determined by the
photocurrent) shunted by a capacitance for short sampling pulses (~ 350ps for
the 7S14)

Bruce
On 28 December 2019 at 12:34 "Carl Hallberg via Groups.Io"
<n9ess=yahoo.com@groups.io> wrote:


Chuck,
I did use blue to red.  Hardly worth mentioning.  Also white has been
mentioned (by me, and others) and it does work as long as spectrum of white
contains the color of receiver LED  (white LED acts like miniature
fluorescent light).  I am not a physicist.  Just an observer.
Carl Hallberg (W9CJH)






On Tuesday, December 24, 2019, 11:33:54 AM CST, Chuck Harris
<cfharris@erols.com> wrote:





I guess it depends on what race you are running.

If the race is to get to 1.3V with the fewest parts, not
so much of a win for IR...

IR LED's, in general were more efficient than the others...
or at least originally, I think blue may have that win
for power today.

I haven't paid much attention to the Frankenstonian mixes
that are the LED's of today.  Today, if it is really bright,
it is probably a blue LED pumping a fluorescent bit to
generate the desired color.
c
Note that he is using like to like combinations.  I would
be most interested in mixing things up a bit.

Perhaps IR driving, or a blue driving one of the others?

-Chuck Harris

Miguel Work wrote:
IR wins! :)

                        Efficiency
IR        1,16        0,85        73,28%
                   
RED        1,9        1,3        68,42%
                   
YELLOW    2        1,2        60,00%
                   
BLUE        3,2        2,3        71,88%










Re: tektronix 7S14 batteries and time base question

Bruce Griffiths
 

For greatest photocurrent in the detector LED, first choose the detector LED for 1.3V and then choose the emitter so that its peak emission is around 50nm shorter in wavelength than the emission from the LED chosen as a detector.
Measuring the detector LED photocurrent is essential, even better measure the detector LEDs slope resistance when biased by the photocurrent.

Bruce

On 28 December 2019 at 12:51 "Carl Hallberg via Groups.Io" <n9ess=yahoo.com@groups.io> wrote:


Hi Bruce,
Then tell us what color driver to use with what color receiver to get approx 1.3V
Carl






On Friday, December 27, 2019, 5:46:43 PM CST, Bruce Griffiths <bruce.griffiths@xtra.co.nz> wrote:





The peak response of a LED acting as a photodiode occurs at a shorter wavelength than its peak emission.
Thus using a pair of red (or green, or blue etc) LEDs isn't the most effective combination.
I have an LTspice simulation that indicates that higher photocurrents are better in this application as the settling time to the sampling transients is reduced.
Since the minority carrier lifetime is typically in the range of 3-120ns for visible LEDs they tend to act as resistors (value determined by the photocurrent) shunted by a capacitance for short sampling pulses (~ 350ps for the 7S14)

Bruce
On 28 December 2019 at 12:34 "Carl Hallberg via Groups.Io" <n9ess=yahoo.com@groups.io> wrote:


Chuck,
I did use blue to red.  Hardly worth mentioning.  Also white has been mentioned (by me, and others) and it does work as long as spectrum of white contains the color of receiver LED  (white LED acts like miniature fluorescent light).  I am not a physicist.  Just an observer.
Carl Hallberg (W9CJH)






On Tuesday, December 24, 2019, 11:33:54 AM CST, Chuck Harris <cfharris@erols.com> wrote:





I guess it depends on what race you are running.

If the race is to get to 1.3V with the fewest parts, not
so much of a win for IR...

IR LED's, in general were more efficient than the others...
or at least originally, I think blue may have that win
for power today.

I haven't paid much attention to the Frankenstonian mixes
that are the LED's of today.  Today, if it is really bright,
it is probably a blue LED pumping a fluorescent bit to
generate the desired color.
c
Note that he is using like to like combinations.  I would
be most interested in mixing things up a bit.

Perhaps IR driving, or a blue driving one of the others?

-Chuck Harris

Miguel Work wrote:
IR wins! :)

                        Efficiency
IR        1,16        0,85        73,28%
                   
RED        1,9        1,3        68,42%
                   
YELLOW    2        1,2        60,00%
                   
BLUE        3,2        2,3        71,88%










Re: tektronix 7S14 batteries and time base question

Carl Hallberg
 

Hi Bruce,
Then tell us what color driver to use with what color receiver to get approx 1.3V
Carl

On Friday, December 27, 2019, 5:46:43 PM CST, Bruce Griffiths <bruce.griffiths@xtra.co.nz> wrote:





The peak response of a LED acting as a photodiode occurs at a shorter wavelength than its peak emission.
Thus using a pair of red (or green, or blue etc) LEDs isn't the most effective combination.
I have an LTspice simulation that indicates that higher photocurrents are better in this application as the settling time to the sampling transients is reduced.
Since the minority carrier lifetime is typically in the range of 3-120ns for visible LEDs they tend to act as resistors (value determined by the photocurrent) shunted by a capacitance for short sampling pulses (~ 350ps for the 7S14)

Bruce
On 28 December 2019 at 12:34 "Carl Hallberg via Groups.Io" <n9ess=yahoo.com@groups.io> wrote:


Chuck,
I did use blue to red.  Hardly worth mentioning.  Also white has been mentioned (by me, and others) and it does work as long as spectrum of white contains the color of receiver LED  (white LED acts like miniature fluorescent light).  I am not a physicist.  Just an observer.
Carl Hallberg (W9CJH)






On Tuesday, December 24, 2019, 11:33:54 AM CST, Chuck Harris <cfharris@erols.com> wrote:





I guess it depends on what race you are running.

If the race is to get to 1.3V with the fewest parts, not
so much of a win for IR...

IR LED's, in general were more efficient than the others...
or at least originally, I think blue may have that win
for power today.

I haven't paid much attention to the Frankenstonian mixes
that are the LED's of today.  Today, if it is really bright,
it is probably a blue LED pumping a fluorescent bit to
generate the desired color.
c
Note that he is using like to like combinations.  I would
be most interested in mixing things up a bit.

Perhaps IR driving, or a blue driving one of the others?

-Chuck Harris

Miguel Work wrote:
IR wins! :)

                        Efficiency
IR        1,16        0,85        73,28%
                   
RED        1,9        1,3        68,42%
                   
YELLOW    2        1,2        60,00%
                   
BLUE        3,2        2,3        71,88%







Re: Trying to bring back a AA501

Jean-Paul
 

Hi there, AA501was design by Bruce Hoffer and Richard Cabot, who later started Audio Precision


Complex disassemble, take photos and notes, get the full service manual.

Most frequent issues are dead tantalum capacitors .


Bon Chance

Jon


Re: tektronix 7S14 batteries and time base question

Bruce Griffiths
 

The peak response of a LED acting as a photodiode occurs at a shorter wavelength than its peak emission.
Thus using a pair of red (or green, or blue etc) LEDs isn't the most effective combination.
I have an LTspice simulation that indicates that higher photocurrents are better in this application as the settling time to the sampling transients is reduced.
Since the minority carrier lifetime is typically in the range of 3-120ns for visible LEDs they tend to act as resistors (value determined by the photocurrent) shunted by a capacitance for short sampling pulses (~ 350ps for the 7S14)

Bruce

On 28 December 2019 at 12:34 "Carl Hallberg via Groups.Io" <n9ess=yahoo.com@groups.io> wrote:


Chuck,
I did use blue to red.  Hardly worth mentioning.  Also white has been mentioned (by me, and others) and it does work as long as spectrum of white contains the color of receiver LED  (white LED acts like miniature fluorescent light).  I am not a physicist.  Just an observer.
Carl Hallberg (W9CJH)






On Tuesday, December 24, 2019, 11:33:54 AM CST, Chuck Harris <cfharris@erols.com> wrote:





I guess it depends on what race you are running.

If the race is to get to 1.3V with the fewest parts, not
so much of a win for IR...

IR LED's, in general were more efficient than the others...
or at least originally, I think blue may have that win
for power today.

I haven't paid much attention to the Frankenstonian mixes
that are the LED's of today.  Today, if it is really bright,
it is probably a blue LED pumping a fluorescent bit to
generate the desired color.
c
Note that he is using like to like combinations.  I would
be most interested in mixing things up a bit.

Perhaps IR driving, or a blue driving one of the others?

-Chuck Harris

Miguel Work wrote:
IR wins! :)

                        Efficiency
IR        1,16        0,85        73,28%
                   
RED        1,9        1,3        68,42%
                   
YELLOW    2        1,2        60,00%
                   
BLUE        3,2        2,3        71,88%







Re: tektronix 7S14 batteries and time base question

Carl Hallberg
 

Chuck,
I did use blue to red.  Hardly worth mentioning.  Also white has been mentioned (by me, and others) and it does work as long as spectrum of white contains the color of receiver LED  (white LED acts like miniature fluorescent light).  I am not a physicist.  Just an observer.
Carl Hallberg (W9CJH)

On Tuesday, December 24, 2019, 11:33:54 AM CST, Chuck Harris <cfharris@erols.com> wrote:





I guess it depends on what race you are running.

If the race is to get to 1.3V with the fewest parts, not
so much of a win for IR...

IR LED's, in general were more efficient than the others...
or at least originally, I think blue may have that win
for power today.

I haven't paid much attention to the Frankenstonian mixes
that are the LED's of today.  Today, if it is really bright,
it is probably a blue LED pumping a fluorescent bit to
generate the desired color.
c
Note that he is using like to like combinations.  I would
be most interested in mixing things up a bit.

Perhaps IR driving, or a blue driving one of the others?

-Chuck Harris

Miguel Work wrote:
IR wins! :)

                        Efficiency
IR        1,16        0,85        73,28%
                   
RED        1,9        1,3        68,42%
                   
YELLOW    2        1,2        60,00%
                   
BLUE        3,2        2,3        71,88%



Re: Tektronix 2465

Reginald Beardsley
 

Jose,

You didn't state a budget. The lowest cost and actually very good option is to buy an ADF4351 based VFO with simple interface such as:

https://www.ebay.com/itm/US-35-4000MHz-RF-Signal-Simple-Generator-Signal-Source-ADF4351-VFO-HXY-D6-V1-02/202853156592

It's entirely adequate and in a nice case, a very useful piece of T&M kit.

If you want really top notch quality calibration references, I'd like to suggest getting the following two items:

http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=124&products_id=295

http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=107&products_id=301

Those will meet your immediate need and also provide metrology grade references for rise time and frequency for many years to come.

Have Fun!
Reg


Re: 465M Junker

KB6NAX
 

Progress report on the 465M junker: After a couple of good sessions I think I found nearly all of the problems. They were all caused by non-expert assaults. The worst was bent contacts in the vertical preamp hybrid socket. Apparently the hybrid was taken out and the contacts clumsily probed. They are of quite soft metal and easily bent down. Four of them were obviously not making contact with the contact pads on the hybrid. After putting the contacts, carefully, right again and washing the contacting surfaces with Caig D5 the vertical channel sprang to life. Only thing I'm waiting for now is the dual input FET for channel 1. On the horizontal side no less than three ribbon cable connectors were mis-connected. Obviously the module was thrown together to be rid of or was worked on by a blind person. One peculiar problem was the sweep time vernier un-cal light would not come on. Amazingly, Tek forgot to provide a ground return trace for the LED circuit so the light never could come on when the vernier is in un-cal (hmmmm, I wonder if the board layout guy went to work for Boeing). The nicest thing about this scope is there is no soot around the high voltage circuits. That means close to zero hours of operating time - no worn out electrolytic capacitors. I'm not looking forward to the eventual calibration exercise but it needs doing. Now to find a replacement for the shattered top cover. Anyone got one for sale?

Arden


Re: TM500 / 5000 Extenders

Gary Neilson
 

Is there a picture of an extender made from these ?
Also where is the board RS274-X files for these ?

Thanks
Gary Neilson


Re: Tektronix 2465

Chuck Harris <cfharris@...>
 

The 50 ohm load resistor in the 2465 is a metal film
resistor that is deposited on the ceramic substrate
of the attenuator module. It is covered with
a temperature sensor film thermistor, and when it
reports that it is too warm, the CPU cuts it out of the
circuit.

To blow it, you have to do something really egregious,
like connect it to a high current supply that can
get the resistor really hot, really quickly.

I would guess that it can protect itself from an insult
in the several watt range. I have never felt the urge
to test it, though.

The manual has this obscure phrase:

5V rms; 0.5W-seconds during any 1-s interval for instantaneous
voltage from 5V to 50V.

Note that 5V -> 0.5W, and 50V -> 50W.

So, I think they are saying it can take 5Vrms for 1 second,
and 50V for 1/100th of a second.

If you can stand a little change in performance, it would not
be impossible to attach a SMD 50 ohm resistor in its place.

As I said earlier, the relays are common problem areas.. both
their contact regions, and the socketed coil pins.

It is a little difficult to remove the attenuator, you have to
remove the bezel, CRT knobs, and front panel assembly, and
several screws reachable from the hole where the front panel
assembly goes, and below the attenuator's bezel extension, and
unsolder a lead from a trimmer cap, and the vertical hybrid...

But, once you have it out of the circuit, everything likely to
be bad can be checked with a DVM. Take it easy on the gold.

-Chuck Harris

satbeginner wrote:

Hi,

There is something wrong with either just the input 50 Ohm resistor, and/or the input attenuator box.

The change when you remove the external 50 Ohm is as expected, a rise in amplitude when you remove it.

However, the fact there is no change when you switch off the internal 50 Ohm terminator, indicates there is a problem there.

Such damage does happen when a too high voltage was inserted while set at internal terminator, that resistor usually is damaged, and, if the voltage was really high, the variable attenuator box behind that resistor is damaged too.

Can you check the same things on Ch2?

Un saludo,
Leo




Re: Tektronix 2465

satbeginner
 

Hi,

There is something wrong with either just the input 50 Ohm resistor, and/or the input attenuator box.

The change when you remove the external 50 Ohm is as expected, a rise in amplitude when you remove it.

However, the fact there is no change when you switch off the internal 50 Ohm terminator, indicates there is a problem there.

Such damage does happen when a too high voltage was inserted while set at internal terminator, that resistor usually is damaged, and, if the voltage was really high, the variable attenuator box behind that resistor is damaged too.

Can you check the same things on Ch2?

Un saludo,
Leo


rigid extender kit: extender pcbs, stripped 7A13 7000 plugin frame, wire and coax $34

John Griessen
 

I have imbalance in my components for 7k extender kits, so this partial kit
deal is offered on a one time basis,
and complete 7k kits are not available until after middle of next year . (Some assembly required...)

The plugin frame from a 7A13 early type has screws, a front plate with a ground terminal and a lamp.
Its rear card edge guide has only one keeper -- it snapped when I removed it. All you need to make an extender frame is to bolt it to the rails with the extender pcb hole that is there ready to use in my pcb.

For $34 I will send:

plugin frame parts:
https://www.ecosensory.com/tek/tek_7k_plugin_frame-1.jpg
https://www.ecosensory.com/tek/tek_7k_plugin_frame-2.jpg

pcb:
https://www.ecosensory.com/tek/TEK_7K_FLEX_production-board-2.jpg
https://www.ecosensory.com/tek/TEK_7K_FLEX_production-board-3.jpg
64+ 2 ft. 24 gauge wires UL1061
12 ft RG174 coax 0.11 inch diameter

Notice that the female connector is missing. That part is out of stock til many months from now.

If you want any small bits from a 7A13 early, I can put them in for no extra shipping, so ask.

John Griessen
clearing out excess stuff before moving to NM


Re: Tektronix 2465

Chuck Harris <cfharris@...>
 

I recently fixed one customer scope whose attenuator
was not making 50 ohms in the 50 ohm position. The problem
turned out to be the latching relay in the attenuator section
had a "patina" on its gold plated coil pins, that was preventing
the coil from having continuity.

A clean up with deOxit red straightened out the problem.

-Chuck Harris

Siggi wrote:

On Fri, Dec 27, 2019 at 07:25 Jose Alfredo <alfredo@itesh.com.br> wrote:

Leo, thanks for helping me. I removed the 50 ohms terminal and things go
worse. See: https://youtu.be/JeFw-dr9V3M

You may have a bad or flaky input attenuator.
Set the scope to DC coupling, and measure the resistance from the inner
conductor of the input to the shell. It should be 1MOhm on the dot across
all vertical settings.
Set the coupling to AC, and you should measure infinite input resistance.
Set the coupling to 50Ohm and you should measure 50Ohm.
If any of those are off, the attenuator has problems.

The contacts on these attenuators can develop oxidation or other problems
that cause them to either not complete the connection, or to go high
resistance. It’s also possible that a previous user has burned out the
50Ohm termination resistor.

<https://youtu.be/JeFw-dr9V3M>



Re: Tektronix 2465

Siggi
 

On Fri, Dec 27, 2019 at 07:25 Jose Alfredo <alfredo@itesh.com.br> wrote:

Leo, thanks for helping me. I removed the 50 ohms terminal and things go
worse. See: https://youtu.be/JeFw-dr9V3M

You may have a bad or flaky input attenuator.
Set the scope to DC coupling, and measure the resistance from the inner
conductor of the input to the shell. It should be 1MOhm on the dot across
all vertical settings.
Set the coupling to AC, and you should measure infinite input resistance.
Set the coupling to 50Ohm and you should measure 50Ohm.
If any of those are off, the attenuator has problems.

The contacts on these attenuators can develop oxidation or other problems
that cause them to either not complete the connection, or to go high
resistance. It’s also possible that a previous user has burned out the
50Ohm termination resistor.

<https://youtu.be/JeFw-dr9V3M>


Re: Tektronix 2465

GerryR <totalautomation1@...>
 

The high-amplitude output is used to stimulate the Tek tunnel diode
pulser for Vertical Transient Response calibration. The unit I made to
replace the Tek Pulser operates at 10 V, so I didn't need the high-amplitude
output called out in the procedure.
The PG506 Cal Gen "standard" output is a 1 KHz square wave
adjustable form 100 uV to 5 V into a 50 ohm load. I used my BK Prec 4045B
Sig Gen for these outputs.
The markers were generated from my Wavetek 801 Pulse generator, good
to 50 MHz. I couldn't verify the 2 nS requirement in the cal procedure.
I used my Wavetek 1001A leveled sinewave RF sig gen to verify
flatness to 300 MHz; the procedure called for verification to 350 MHz.

GerryR
KK4GER

----- Original Message -----
From: "amirb" <amir.borji@gmail.com>
To: <TekScopes@groups.io>
Sent: Friday, December 27, 2019 7:36 AM
Subject: Re: [TekScopes] Tektronix 2465


GerryR,
what signal/pulse generators did you use specifically? specially to replace
the PG506


I think somewhere there is a need for pulses with high amplitude like 25V
or 50V, isn't it?


Re: Tektronix 2465

GerryR <totalautomation1@...>
 

Jose,
You need a good frequency generator to replace the PG506 calibration generator and a good pulse generator (variable duty cycle and fast rise time) to replace the TG501 Marker generator. The pulser is only used for one of the cal procedures.

GerryR
KK4GER

----- Original Message -----
From: "Jose Alfredo" <alfredo@itesh.com.br>
To: <TekScopes@groups.io>
Sent: Friday, December 27, 2019 7:30 AM
Subject: Re: [TekScopes] Tektronix 2465


Thanks Gerry!

Yes. I don't have those equipments (TG501 and PG506). Leo Bodnar pulser
can replace the diode and the specific TG501 and PG506 units?

Em 27/12/2019 09:17, GerryR escreveu:
Jose,
I have the 2465A and have been through the calibration procedure a few times due to the fact that I messed up when trying to change the battery backup module, which I believe you do not have on the 2465; that's a blessing. The calibration procedure for the 2465A called for a PG506 Calibration Generator and a TG501 Marker Generator for doing the calibration. I looked up the output specs of each and ended up using a good frequency generator and a good pulse generator to duplicate the "standard" output signals of the PG506 and TG501. That worked fine. The test procedure also called for a tunnel diode pulser, which I downloaded the specs for and made one that was suitable enough to get the job done, but I believe that Leo Bodnar makes a pulser that is more than adequate to get the job done and can be purchased from him online. Once I got through all the cal procedures, everything worked fine and all measurements were on target. It was quite a learning experience, but was fun as well.

GerryR
KK4GER


----- Original Message ----- From: "Jose Alfredo" <alfredo@itesh.com.br>
To: <TekScopes@groups.io>
Sent: Friday, December 27, 2019 5:16 AM
Subject: Re: [TekScopes] Tektronix 2465


Gerry, yesterday I adjusted the 10V voltage and runned through the crt
adjustment procedures. The screen is now absolutely normal. It could,
indeed, have been a previous attempt to calibrate the oscilloscope. Now
I'm studing how to finish all the steps required to finish the calibration.

One thing I noticed is that the vertical readings are wrong. when I
input a 2 Vpp saquare wave (or any other wave form), it shows something
near 2.5 Vpp. I think the self call procedures will repair this. What do
you think about that?

Em 26/12/2019 21:09, GerryR escreveu:
One of the calibration procedures produces those series of dots when setting the vertical limits, if I remember correctly. It would appear that whatever initiates that procedure is somehow "stuck on." I'll try to find which procedure it is and report back.

GerryR
KK4GER


----- Original Message ----- From: "Jose Alfredo" <alfredo@itesh.com.br>
To: <TekScopes@groups.io>
Sent: Thursday, December 26, 2019 3:38 PM
Subject: [TekScopes] Tektronix 2465


Hello everybody,

I just bought this Tektronix 2465 oscilloscope here in Brazil. When turned on, you can see blinking dots on both, upper and down fields, that show the unit status - see my video on https://youtu.be/NDc4gKDbCQI. Have any of you had any similar experience that could help me fixing it?

Thanks

Jose Alfredo C. Santos










20081 - 20100 of 182428