Topics

Tektronix 2465b Boo Boo


squirrel@...
 

Hi guys my first post here be gentle.

I have made a big Boo Boo with my scope
Without reading or joining any Tek scope forums but just glancing through the manuals I decided to jump the "cal" and have a look at the settings that where there
I don't remember exactly what I did, but I think I just scrolled through and then exited I know for a fact that I have never adjusted any thing and I never set or entered any parameters.
But I now have the dreaded 2v????????/?? at the display bottom.
So the question is can I recover from this mistake or does the scope now require a full cal
thanks


satbeginner
 

If you did not make a backup of the A5 Dallas contents, a full cal is what needs to be done....


 

Ok, try doing the exerciser 3 routine (cycle error clear). See the service manual for the procedure. It is on pdf page 237 on my Artek manual.

Regards,

Tom

On 7/7/2020 8:34 AM, squirrel@... wrote:
Hi guys my first post here be gentle.

I have made a big Boo Boo with my scope
Without reading or joining any Tek scope forums but just glancing through the manuals I decided to jump the "cal" and have a look at the settings that where there
I don't remember exactly what I did, but I think I just scrolled through and then exited I know for a fact that I have never adjusted any thing and I never set or entered any parameters.
But I now have the dreaded 2v????????/?? at the display bottom.
So the question is can I recover from this mistake or does the scope now require a full cal
thanks


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squirrel@...
 

Wow what a great group thanks for that as soon as I get 5 mins I will give it go
Cheers Tom.


squirrel@...
 

Thanks satbeginner I hope that Toms solution may work thanks for the help


Chuck Harris
 

If you enter just about any of the calibration routines, and
don't work the routine to completion, but rather abort it in
the middle, you will get the dreaded ??????? indication of an
uncalibrated scope.

The message indicates that the calibration complete flag,
when tested at power on, showed false.

The only sure way to repair the "damage" is to redo the routine
you aborted.

Sometimes, you can convince the scope to reset the flag
by using exercise 3, as Tom Miller described. Assuming you didn't
actually change anything, it should work.

I don't have any great experience trying to fool the scope into
reporting a good calibration. This is because I calibrate scopes,
and I always do a full calibration when such a scope gets into
my hands.

-Chuck Harris

squirrel@... wrote:

Wow what a great group thanks for that as soon as I get 5 mins I will give it go
Cheers Tom.





squirrel@...
 

Thank for that Chuck I live in Australia in a small country town I have no access to the required equipment to do a full cal I did ring a company in the city and the kick off price for a full cal was $1200.00 not to mention the exuberant freight cost this is way more than the scope is worth.
However I am retired and a hobbyist only so close enough is good enough for me.
I'm about to order a DS1225Y from Digikey I see there are 4 different ones 2 available "DS-1225Y-150+-ND" DS-1225Y-200+-ND" which one should I get the 150 or 200
I also notice these are Maxim chips.
I have a Willem 4.1 burner which list the DS1225Y .
Cheers


Tam Hanna
 

Hello,

in case you do need a full cal:

https://www.youtube.com/watch?v=m7adJq5xMHE


A friend of mine has a whole gaggle of videos on the topic...


Tam

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With best regards
Tam HANNA

Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at https://www.instagram.com/tam.hanna/


Chuck Harris
 

There is really only one issue with the 1225 you use,
and that is it must be the sort that trips at the right
voltage. The speed is of no consequence for such a slow
microprocessor.

Dallas as a company doesn't exist anymore. Maxim bought
them.

I use DS1225AD-200IND+'s. I didn't know the "Y" was still
available. It wasn't for a while.

Whatever method you use to remove the part, keep the
temperature down. I do not recommend using solder wick,
as the pins have to get way too hot, and the wick never
gets all of the solder, leading to tearing out plated-thru
holes. A desoldering station is essential, in my opinion.

Also, there are traces right tight against the solder
pads. It is very easy to break one of them if you get
too aggressive.

-Chuck Harris

squirrel@... wrote:

Thank for that Chuck I live in Australia in a small country town I have no access to the required equipment to do a full cal I did ring a company in the city and the kick off price for a full cal was $1200.00 not to mention the exuberant freight cost this is way more than the scope is worth.
However I am retired and a hobbyist only so close enough is good enough for me.
I'm about to order a DS1225Y from Digikey I see there are 4 different ones 2 available "DS-1225Y-150+-ND" DS-1225Y-200+-ND" which one should I get the 150 or 200
I also notice these are Maxim chips.
I have a Willem 4.1 burner which list the DS1225Y .
Cheers







tekscopegroup@...
 

At the risk of contradicting the master of the 2465 scopes -Obi Wan Harris- when I removed my NVRAM chip I used a simple soldapullt solder sucker (albeit one of the good quality ones - EDSYN) and in the end the chip just fell off the board by itself after the last pin was cleared. Even the ground pin was cleared quite easily without using anywhere near excessive heat. Just make sure to first "wet" each joint well with fresh good quality solder (for me that would be Kester 44), and that will make it much easier for the thru holes to be cleared on the first try. So even tough I would agree that a desoldering station is probably the best way to do this job, or at least the one with the least risk to the board, if you are in the middle of nowhere don't be afraid to use simpler methods as long as you are comfortable with it and have the proper expertise in using the desoldering tool of your choice. And be patient, don't rush things making sure every single pin is clear and confirmed loose before you start pulling on the chip. Sometimes the pin can still be slightly stuck even tough the hole looks clear, then you can try wiggling the pin a bit towards the center of the hole and most times it will just break free. Otherwise refill the hole with some more fresh solder and try again. Hope that helps.

BTW get your replacement NVRAM from a reputable place like Mouser (or Digikey), never from Ebay, specially avoid if it comes from Chinaland, as it might be an old relabeled chip with an internal battery that is well past its expiration date. Also get a good quality low profile socket to reinstall the new chip. I got mine from Mouser, one of the machined pin type, although some people say its best not to use this type but rather the convention kind. In any case it worked for me. Good luck with the repair, and please report back your progress.


 

Please forgive me for asking but I can't quite follow.
The OP told us that his 'scope was working fine but that he hadn't been able to resist the temptation to enable "cal" mode and play around. That resulted in the bottom line with lots of question marks. As far as we know - or hope, the 'scope is still about as much in calibration as before.
He also told us that doing a cal. is no option for him, technologically nor financially.

Where does the advice come from to replace the NVRAM, except for the fact that it may lose its memory soon? It may not for a while if left untouched. If it does during replacement (that has happened before), he won't be able to recover.

Why not just advise the OP to follow Chuck's advice to step through the procedure he started but didn't finish or first do an exercise 3 and hope for the best? When restarting - and finishing the procedure the OP started, he should finish it all the way *without* changing anything, if possible.
After performing his steps, the OP should switch off, then on.

Raymond


Chuck Harris
 

The NVRAM swap was the idea of the original poster... not any
of us.

The only advice given was Exercise 3 by Tom, and an explanation
of how the problem occurs by me.

After he asked what NVRAM to use, I told him, and warned about
trying to remove the old NVRAM using substandard means.

Some of the calibration steps will not allow you to step through
them without making changes... for example: the vertical calibration,
the trigger calibration, the parametric calibration, all do their thing
automagically using the specified voltage coming from your voltage
calibrator.

If the voltage calibrator is not there, the routine will fault with a
bunch of dots, and if you quit early, a bunch of question marks.

I wish there were a way of aborting without making changes, but tek
didn't do that.

Why do I wish that? On more than a few occasions, I have finished a
routine, and with my head running on autopilot, re-entered the just
finished calibration step, requiring me to do it all over again, or
suffer the ???? display.

-Chuck Harris

Raymond Domp Frank wrote:

Please forgive me for asking but I can't quite follow.
The OP told us that his 'scope was working fine but that he hadn't been able to resist the temptation to enable "cal" mode and play around. That resulted in the bottom line with lots of question marks. As far as we know - or hope, the 'scope is still about as much in calibration as before.
He also told us that doing a cal. is no option for him, technologically nor financially.

Where does the advice come from to replace the NVRAM, except for the fact that it may lose its memory soon? It may not for a while if left untouched. If it does during replacement (that has happened before), he won't be able to recover.

Why not just advise the OP to follow Chuck's advice to step through the procedure he started but didn't finish or first do an exercise 3 and hope for the best? When restarting - and finishing the procedure the OP started, he should finish it all the way *without* changing anything, if possible.
After performing his steps, the OP should switch off, then on.

Raymond




 

On Wed, Jul 8, 2020 at 07:00 PM, Chuck Harris wrote:


The NVRAM swap was the idea of the original poster... not any
of us.
I'm under the impression that the OP thought he'd solve his problem by replacing the NVRAM with a nice, clean one. You're right that he came up with the idea but our reactions didn't make it clear that unless he buys one of those preloaded NVRAMs containing "some general" calibration data, he won't solve his problem that way. BTW, I'm not a believer in the preloaded NVRAMs but of course, I'm biased because I have the equipment and I have calibrated these 'scopes - and I have replaced NVRAMs, both with new ones and with FRAMs. "Preloaded" calibration data may be good enough for some/many, don't know. I'd guess calibration may be 2 - 5% off, right?

Raymond


satbeginner
 

Putting in a pre-loaded Dallas or Fram will remove the 'not calibrated' indication (?????? or ............), but this will mean the scope from now on is

"Not Calibrated",

only it will not be visible to a user.
The error could be anything from 1% to 15 or more %, depending on the parameter used.
Timebase, Amplitude, Delay, etc.

Putting in a pre-loaded replacement is the ostrich way....

The only real way to go is calibration.

Just my 2cts...

Leo


Chuck Harris
 

I am of the general opinion that the only reason to buy
a "pre-calibrated" DS1225, is because you are selling your
scope, and you want to fool the potential buyers into
thinking the scope is calibrated.

Kind of the tektronix version of turning back the odometer
on a used car.

I hope he wasn't thinking a pre-calibrated NVRAM is a
legitimate solution to any real problem.

-Chuck Harris

satbeginner wrote:

Putting in a pre-loaded Dallas or Fram will remove the 'not calibrated' indication (?????? or ............), but this will mean the scope from now on is

"Not Calibrated",

only it will not be visible to a user.
The error could be anything from 1% to 15 or more %, depending on the parameter used.
Timebase, Amplitude, Delay, etc.

Putting in a pre-loaded replacement is the ostrich way....

The only real way to go is calibration.

Just my 2cts...

Leo




James Theonas
 

Hi Guys, I own the 2465b and I purchased a fm16w08-sg on a conversion board to fit in the ds1225y place. As a test, I flashed the chip using the calibration file available in the files section of our group. everything seems to have gone well and verification is good after some tests. Now my question. If I want my true calibration data (2465b working fine) I need to remove the ds1225y copy it and program the new chip with said calibration data. Am I correct in my assumption? Only other way is full recalibration? (I don't know where I can do that here in Greece).

Thanks for any answer in advanceDimitris Theonas

On Wednesday, July 8, 2020, 8:44:57 PM GMT+3, Chuck Harris <cfharris@...> wrote:

I am of the general opinion that the only reason to buy
a "pre-calibrated" DS1225, is because you are selling your
scope, and you want to fool the potential buyers into
thinking the scope is calibrated.

Kind of the tektronix version of turning back the odometer
on a used car.

I hope he wasn't thinking a pre-calibrated NVRAM is a
legitimate solution to any real problem.

-Chuck Harris

satbeginner wrote:
Putting in a pre-loaded Dallas or Fram will remove the 'not calibrated' indication (?????? or ............), but this will mean the scope from now on is

"Not Calibrated",

only it will not be visible to a user.
The error could be anything from 1% to 15 or more %, depending on the parameter used.
Timebase, Amplitude, Delay, etc.

Putting in a pre-loaded replacement is the ostrich way....

The only real way to go is calibration.

Just my 2cts...

Leo




Chuck Harris
 

The calibration data is purely digital, so, it can
be copied from one NVRAM to another without consequence.

The actual calibration data only amounts to about 170 bytes
of data in the entire NVRAM. The rest of the space is the
CPU's stack and data area, and is cleared every time you
turn the scope on.

Greece is the source of a lot of the replacement parts
for the 2465 family. Clearly there are folks in Greece
that know about this unit. I would suggest you get into
contact with the Greek guy on ebay, that sells parts,
and ask him. Q-Service, I think.

-Chuck Harris

James Theonas via groups.io wrote:

Hi Guys, I own the 2465b and I purchased a fm16w08-sg on a conversion board to fit in the ds1225y place. As a test, I flashed the chip using the calibration file available in the files section of our group. everything seems to have gone well and verification is good after some tests. Now my question. If I want my true calibration data (2465b working fine) I need to remove the ds1225y copy it and program the new chip with said calibration data. Am I correct in my assumption? Only other way is full recalibration? (I don't know where I can do that here in Greece).

Thanks for any answer in advanceDimitris Theonas
On Wednesday, July 8, 2020, 8:44:57 PM GMT+3, Chuck Harris <cfharris@...> wrote:

I am of the general opinion that the only reason to buy
a "pre-calibrated" DS1225, is because you are selling your
scope, and you want to fool the potential buyers into
thinking the scope is calibrated.

Kind of the tektronix version of turning back the odometer
on a used car.

I hope he wasn't thinking a pre-calibrated NVRAM is a
legitimate solution to any real problem.

-Chuck Harris

satbeginner wrote:
Putting in a pre-loaded Dallas or Fram will remove the 'not calibrated' indication (?????? or ............), but this will mean the scope from now on is

"Not Calibrated",

only it will not be visible to a user.
The error could be anything from 1% to 15 or more %, depending on the parameter used.
Timebase, Amplitude, Delay, etc.

Putting in a pre-loaded replacement is the ostrich way....

The only real way to go is calibration.

Just my 2cts...

Leo










Ken Eckert
 


James Theonas
 

Agreed but they also sell the ds1225y pre programmed with calibration data. How would I know if the scope was precalibrated or if they just popped in a pre flashed chip?

On Friday, July 10, 2020, 12:27:47 AM GMT+3, Ken Eckert <eckertkp@...> wrote:

https://www.qservice.tv/


James Theonas
 

re-calibrated not pre-calibrated

On Friday, July 10, 2020, 12:27:47 AM GMT+3, Ken Eckert <eckertkp@...> wrote:

https://www.qservice.tv/