Author Topic: Tek 2465A question  (Read 1195 times)

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Offline GerryR

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Tek 2465A question
« on: October 05, 2019, 05:49:48 pm »
I am getting a "Test 04 Fail 03" diagnostic error on power-up, which I understand is a calibration related error, but searching online and through the manual, I have been unable to come up with the details of the "03" part of the error.  Any help on specifics other than the general "Calibration Related Error?"  Thanks in advance.
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Offline mr.fabe

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Re: Tek 2465A question
« Reply #1 on: October 05, 2019, 07:09:52 pm »
03 = Parity error with out of limits and good checksum

When the CMOS RAM's battery goes dies, or there a problem with the CMOS ram's parity, the scope may detect that as an error, and the Test 04 Fail XX message will be displayed.
 

Offline GerryR

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Re: Tek 2465A question
« Reply #2 on: October 05, 2019, 08:06:48 pm »
03 = Parity error with out of limits and good checksum

When the CMOS RAM's battery goes dies, or there a problem with the CMOS ram's parity, the scope may detect that as an error, and the Test 04 Fail XX message will be displayed.

How is this remedied?  There were no errors before the battery was changed (battery was dated 07 87!), so I am assuming that calibration data was corrupted, and a re-cal is in order??  Am I on the right track (unfortunately)?
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Offline w9gb

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Re: Tek 2465A question
« Reply #3 on: October 05, 2019, 09:40:21 pm »
TEST 04 Error .... Flow charted
https://youtu.be/YubzXhE27dY

There are TWO Batteries in tbe 2400 series scopes.
Did you change BOTH ?
« Last Edit: October 05, 2019, 09:42:09 pm by w9gb »
 

Offline GerryR

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Re: Tek 2465A question
« Reply #4 on: October 05, 2019, 10:04:04 pm »
I've been through the "Flow Chart" for Test 04 failure; unfortunately it doesn't address the "03" error.  I only replaced the battery on the A5 control board.  I didn't know there was a second battery.  Can you enlighten me as to where it is?  Also, in the video, he mentions "hidden" calibration procedures.  Is there a list of these somewhere?  Thank you for your input.

I did check the cal ram, and from 00 to 6E there should be odd parity.  About 10 of the last locations have even parity, which I am assuming is the problem.  I haven't gotten far enough to figure what that means and what parameters are in those locations.
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Offline mr.fabe

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Re: Tek 2465A question
« Reply #5 on: October 05, 2019, 11:24:08 pm »
03 = Parity error with out of limits and good checksum

When the CMOS RAM's battery goes dies, or there a problem with the CMOS ram's parity, the scope may detect that as an error, and the Test 04 Fail XX message will be displayed.

How is this remedied?  There were no errors before the battery was changed (battery was dated 07 87!), so I am assuming that calibration data was corrupted, and a re-cal is in order??  Am I on the right track (unfortunately)?
Your assumptions are correct and you are on the right track. A re-calibration is in order.  This will fix the errors that were flagged when you changed the battery.
 

Offline MarkL

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Re: Tek 2465A question
« Reply #6 on: October 06, 2019, 05:00:56 pm »
...
There are TWO Batteries in tbe 2400 series scopes.
Did you change BOTH ?
There's only one battery in the 2465A.
 

Offline Tom45

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Re: Tek 2465A question
« Reply #7 on: October 06, 2019, 05:46:11 pm »
...
There are TWO Batteries in tbe 2400 series scopes.
Did you change BOTH ?
There's only one battery in the 2465A.

And I believe no battery in the 2465.
 

Online med6753

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Re: Tek 2465A question
« Reply #8 on: October 06, 2019, 06:40:33 pm »
...
There are TWO Batteries in tbe 2400 series scopes.
Did you change BOTH ?
There's only one battery in the 2465A.

And I believe no battery in the 2465.

Correct. Uses EAROM to store cal data.
 
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Offline GerryR

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Re: Tek 2465A question
« Reply #9 on: October 07, 2019, 03:13:35 pm »
...
There are TWO Batteries in tbe 2400 series scopes.
Did you change BOTH ?
There's only one battery in the 2465A.

I would call that negative development progress, where a dead battery makes a 'scope almost useless without recal.  Maybe they didn't expect people to hang onto them that long!



And I believe no battery in the 2465.

Correct. Uses EAROM to store cal data.
Still learning; good judgment come from experience, which comes from bad judgment!!
 

Offline mr.fabe

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Re: Tek 2465A question
« Reply #10 on: October 08, 2019, 04:12:19 am »
...
There are TWO Batteries in tbe 2400 series scopes.
Did you change BOTH ?
There's only one battery in the 2465A.

I would call that negative development progress, where a dead battery makes a 'scope almost useless without recal.  Maybe they didn't expect people to hang onto them that long!

And I believe no battery in the 2465.
Based on the OP's posts, it appears that the scope did not have a "dead battery" rendering the scope useless.  Unfortunately, the loss of calibration information appears to be a self-inflicted wound.  On the bright side, the unit can have a fresh makeover on the passives that typically fail on this unit, cleaning, etc. prior to performing the calibration procedure.  All is not lost.  Just an opportunity to keep this scope running for many years to come.
 

Offline GerryR

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Re: Tek 2465A question
« Reply #11 on: October 08, 2019, 03:56:21 pm »
You are right, the battery was not dead, but the date code on it was 07-87 so how much longer would it have gone - who knows.  However, a word of caution.  I thought I took every precaution when installing the new battery.  The board was out of the 'scope, obviously, and a substitute battery was attached before removing the old battery.  Sounds good, so far.  No problem installing the new battery, but Test 04 Fail on power-up.  So what went wrong, and how did the cal memory get contaminated?  Just a guess, but I was working on a static free mat, which I had laid the board on.  I had problems years ago working on a static free mat with cmos circuitry;  I didn't give it a thought, but there is enough conduction in the mat to screw things up.  Just a guess, and a word of caution. 
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Offline mr.fabe

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Re: Tek 2465A question
« Reply #12 on: October 08, 2019, 04:16:31 pm »
You are right, the battery was not dead, but the date code on it was 07-87 so how much longer would it have gone - who knows.  However, a word of caution.  I thought I took every precaution when installing the new battery.  The board was out of the 'scope, obviously, and a substitute battery was attached before removing the old battery.  Sounds good, so far.  No problem installing the new battery, but Test 04 Fail on power-up.  So what went wrong, and how did the cal memory get contaminated?  Just a guess, but I was working on a static free mat, which I had laid the board on.  I had problems years ago working on a static free mat with cmos circuitry;  I didn't give it a thought, but there is enough conduction in the mat to screw things up.  Just a guess, and a word of caution.
You can try one more thing but I'm not sure it will help.  Try the EXER 03 (Clear Cycle Error) routine listed in the service manual.  If that doesn't clear the error, then it's definitely calibration time.
 

Offline GerryR

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Re: Tek 2465A question
« Reply #13 on: October 08, 2019, 06:41:46 pm »
Unfortunately, been there, done that; it needs the cal.  I was wondering if anyone here has done the cal, and if there is a minimum set of procedures that will get it back up and running.  The procedures in the manual are not particularly complicated, but some of the required test equipment are not the usual home-lab stock items. Does anyone know of any work-around procedures?  I have a few ideas that I am going to try before I think about sending it out; if they work, I will post the results.
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Offline jonpaul

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Re: Tek 2465A question
« Reply #14 on: October 08, 2019, 08:21:47 pm »
Gerry the 2465A cal takes about 3-6 hrs with exactly the specified TEK cal gens, if one is experienced.

Many steps are very critical in gen requirements.

Failing ( out of limit) one step, results in no CAL data save.

See the very fine 2465 teardown threads (63 pages) and the TEK scopes  groups.io for more information.

I have worked on 5 of them now and still get some steps wrong!

But lots of fun to learn the proceedure.

Enjoy

Jon
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Online alpher

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Re: Tek 2465A question
« Reply #15 on: October 09, 2019, 01:36:24 am »
In case of scrambled calibration constants only (due to dead battery for example) the calibration will not be that long.
All you have to do is basically 2 or 3 sections out of calibration routines, I believe CAL-01, 02 are a must Maybe 03 or more, don't remember exactly, but it is easy to figure it out as you go along.
Of all these only CAL-01 (horizontal) is rather involved and requires rather exotic pulse gen. capable of 2ns pulses, tek TG501 is the one that tektronix requires in the manual.
They call it a marker generator and I really suggest you get a hold of one.
The second thing you'll need is a "Calibration generator" , again tek calls for PG506,
but this time is not strictly necessary.
Even though I do have one and used it to calibrate 2465A, I repeated the calibration using modified FY6600 and it went fine.
Even doing it for the first time it didn't take me more that 2hr total, with practice it should take much less time.
Couple of pointers, make sure that you're following the CAL procedure for the correct serial number of your scope ! (cal. procedures for later serials are at the very end of the manual).
You will need another scope for the procedure, will be easier if that scope bandwith was >100MHz (I've done it with 1054Z, but at the fastest sweeps in CAL-01 it was sort of a guesswork :-[), also you will need a 50 \$\Omega\$ inline terminator if your second scope doesn't have 50 \$\Omega\$ inputs.
A couple of BNC cables and you god to go.
And don't be scared it is fun (you will learn how to count to 28 :) :)).


 

Offline jonpaul

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Re: Tek 2465A question
« Reply #16 on: October 09, 2019, 06:51:09 am »
Alpher, the cal routine for lost memory really should have every step and start with power supply and DAC.

Proceedure depends on serial number, options and model number.

The transient align is difficult as it needs some 50 ohm precision cables  and 2, 2.5 and 5X BNC attenuators and very fast pulse generator, like PG506 or Leo Bodnar pulser.

Doing a partial cal is OK but the scopes will not be in spec.
Finally some of the steps interact and are itérative.

Just my thoughts


Jon

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Offline GerryR

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Re: Tek 2465A question
« Reply #17 on: October 09, 2019, 12:27:06 pm »
I'm too old to be scared of much in electronics; just lacking some equipment and accessories for this calibration.  I have been through some of the calibration procedures; messed up some of the Cal 01 procedure due to a lack of understanding of some of the requirements.  I downloaded the PG506 and TG501 manuals to get some clarification of what signals were needed for the calibration.  Just waiting for a couple of attenuators that I ordered.  I did make a "Normalizer," as it seems that anything related to these older 'scopes is thought to be "gold."  And, I will detail the test procedure that I use, and the equipment / accessories, just in case I live long enough for the new battery to die.   :-\

Thank you for all the input.

Just for the record, I contacted Tektronix for a calibration quote and was told they no longer (since 1993  ::)) "support" the 24XX series scopes.  I would think that "calibration" would fall under a different category, but what do I know.  Also, just for reference, I have quotes in the $350.00 to $500.00 range from independent cal companies for the 2465A.  I can get some pretty decent equipment to do the job for that amount.
« Last Edit: October 10, 2019, 10:57:20 am by GerryR »
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Online alpher

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Re: Tek 2465A question
« Reply #18 on: October 09, 2019, 01:16:44 pm »
Alpher, the cal routine for lost memory really should have every step and start with power supply and DAC.

Proceedure depends on serial number, options and model number.

The transient align is difficult as it needs some 50 ohm precision cables  and 2, 2.5 and 5X BNC attenuators and very fast pulse generator, like PG506 or Leo Bodnar pulser.

Doing a partial cal is OK but the scopes will not be in spec.
Finally some of the steps interact and are itérative.

Just my thoughts


Jon

Does the transistent align stores anything into the calibration constants memory?
I really don't remember.
 

Offline jonpaul

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Re: Tek 2465A question
« Reply #19 on: October 09, 2019, 05:29:49 pm »
The transient align cal has some steps that are L, C or trimpot adjustable but other steps are indeed stored in the cal constant memory.

These interact and can be trimmed iteratively.

Contact me via email if you want a quote from a pro ( not me !)

Jon
Jon Paul
 

Offline GerryR

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Re: Tek 2465A question
« Reply #20 on: October 15, 2019, 11:36:20 am »
I started into the recal (still waiting on a couple of components), but I have a couple of questions.  Once finished with the partial calibration, I got a Test 04 fail 02, which is an "out of limits" failure.  Is there a way to tell what is out of limits?  Also, can anyone tell me what the pulse looks like coming out of the Tunnel Diode Pulser?  From the schematic, it looks as though transistor turns on and when the threshold of the tunnel diode is reached, a sharp falling edge is produced.  Is this correct?
« Last Edit: October 15, 2019, 11:38:26 am by GerryR »
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Online alpher

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Re: Tek 2465A question
« Reply #21 on: October 15, 2019, 01:40:58 pm »
You don't need tunnel pulser for restoring scrambled calibration constants.
 

Offline GerryR

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Re: Tek 2465A question
« Reply #22 on: October 15, 2019, 03:46:03 pm »
You don't need tunnel pulser for restoring scrambled calibration constants.

Why not?
Still learning; good judgment come from experience, which comes from bad judgment!!
 

Offline jonpaul

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Re: Tek 2465A question
« Reply #23 on: October 15, 2019, 04:05:42 pm »
Strongly recommend to read the full calibration proceedure.

The transient response calibration uses a fast pulse eg PG506.

The very fine Leo Bodnar pulser is only £50 and is 40 ps edge.

The cal constant memory indeed holds some transient cal data, but many adjustments are L, C or R.

Just the ramblings of an old retired EE

Enjoy

Jon
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Offline GerryR

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Re: Tek 2465A question
« Reply #24 on: October 15, 2019, 04:22:17 pm »
Strongly recommend to read the full calibration proceedure.

The transient response calibration uses a fast pulse eg PG506.

The very fine Leo Bodnar pulser is only £50 and is 40 ps edge.

The cal constant memory indeed holds some transient cal data, but many adjustments are L, C or R.

Just the ramblings of an old retired EE

Enjoy

Jon

I like the ramblings of old retired EE's; I are one too!  ;)
Still learning; good judgment come from experience, which comes from bad judgment!!
 


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