Topics

2465B, 2467B CAL sequence

Jean-Paul
 

Hello All! After a few years of delay and getting A5 boards SMD reworked and socketed, and fixinf fans and graticule lamps, yesterday I finally go bewck to the "gang of 4" scopes!



The 4 scopes are on the bench after NVRAM and battery replacement, 2 of the 4 retained CAL and 2 loaded with a stock image RAM as they were wiped.

I Did a quick power supply V, H and V cal and image check

2 are 100% (did not loose CAL NVRAM) and the remaining 2465B, 2467B are off about 1-4% H cal and similar in VCAL.

Before starting CAL 01 and then CAL 02: Would you recommend to do the CRT Cal as it affects X and Y axis sensitivity? Are the CRT CAL constants also stored in NVRAM?

Or could I save some time and just do CAL 01, 02?

Alternative is a full CAL on all 4 but that will takes days of time.

Open to all opinions from you veterans out there!


Many thanks!

Jon

Chuck Harris
 

In my not so humble opinion, the best way is
to start from the beginning of the calibration
section, and work to the end.

That said, the CRT adjustments are self
contained, they are section 8, and they are all
computer driven, manual adjustments. Things
like CRT grid current, rotation, ... you can
read the book too!

They can be done at anytime you wish, but should be
done first, because when they are way out, you
can hardly read the screen to do any other calibration.
And, doing the CRT adjustments before the h and v
automatic sections makes it easier for you, as the
markers will align with the screen graticules.

Also, notice that the manual has two sections for
CRT adjustments: 2467B and 2465B. Write something
on the first page of each of those sections to
call attention to which scope they belong to.

I can't tell you how many times I tried to do the
2467B's CRT adjustments on a 2465B, before I marked
the sections.

And, yes, even after all of the calibrations I have
done, I still go through the book when calibrating.

-Chuck Harris

Jean-Paul wrote:

Hello All! After a few years of delay and getting A5 boards SMD reworked and socketed, and fixinf fans and graticule lamps, yesterday I finally go bewck to the "gang of 4" scopes!



The 4 scopes are on the bench after NVRAM and battery replacement, 2 of the 4 retained CAL and 2 loaded with a stock image RAM as they were wiped.

I Did a quick power supply V, H and V cal and image check

2 are 100% (did not loose CAL NVRAM) and the remaining 2465B, 2467B are off about 1-4% H cal and similar in VCAL.

Before starting CAL 01 and then CAL 02: Would you recommend to do the CRT Cal as it affects X and Y axis sensitivity? Are the CRT CAL constants also stored in NVRAM?

Or could I save some time and just do CAL 01, 02?

Alternative is a full CAL on all 4 but that will takes days of time.

Open to all opinions from you veterans out there!


Many thanks!

Jon

Jean-Paul
 

Chuck as always your sage advice is spot on!

Another question is the transient response adjustment all analog pot and cap tweaks or are calconstants storned in NVRAM?

À BIENTÔT


Jon

Chuck Harris
 

It is a little of both. There are two networks
of capacitors, pots, and inductors that manually
get tweaked for best shape, and there is a set of
constants that adjust a bias in the channel switch
that gets stored in the NVRAM.

-Chuck Harris

Jean-Paul wrote:

Chuck as always your sage advice is spot on!

Another question is the transient response adjustment all analog pot and cap tweaks or are calconstants storned in NVRAM?

À BIENTÔT


Jon



Jean-Paul
 

Dear Chuck: Last question (hopefully!)

I need to CAL all 4 scopes, 2465B/2467B. I have required equipment, fixtures, etc (TM501, PG506, precision cable, atten)

a/ Do you recommend do a complete CAL on scope 1, proceed to scope 2 etc

OR


Setup first test eg PSU/DAC cal, run on all 4 scopes, proceed to CRT setup on all 4, then CAL 01 on all 4?

b/ I might have to interrupt the sequence eg do CAL 01, CAL 02 on one day to all 4 and then resume at CAL 03 etc the next day.

Is Each CAL procedure is independent of the others, thus start CAL 01, complete and exit>>stored in NVRAM, proceed to CAL 02

OR must EVERY CAL 01-08 be done in order and finished before ALL are recorded in NVRAM?

Many thanks again!

Jon

Chuck Harris
 

I think it is better for a non production (manufacturer) to
go through the entire calibration for each scope separately and
fully to completion, before moving on to the next scope.

I could see where a production line might want to have a technician
specialize on only one step (CAL06 Transient Response), but that
would only work if the volume of scopes available for calibration
would support that kind of specialization. (eg. have enough scopes
so that a technician could be kept busy doing just CAL01...)

The NVRAM constants are stored as you go, and the checksums
are computed when you finish a full calibration step... eg. CAL01.

So, if you get tired after finishing CAL03, and want to quit for
the night, by all means do so. If you simply have to take a break
at, say, CAL03, step 13, do so, but leave the step running.

(By quit, I mean press A/B and leave the calibration routine.)

Always complete a major routine (e.g. CAL03) before quitting the
calibration routine.

-Chuck Harris

Jean-Paul wrote:

Dear Chuck: Last question (hopefully!)

I need to CAL all 4 scopes, 2465B/2467B. I have required equipment, fixtures, etc (TM501, PG506, precision cable, atten)

a/ Do you recommend do a complete CAL on scope 1, proceed to scope 2 etc

OR


Setup first test eg PSU/DAC cal, run on all 4 scopes, proceed to CRT setup on all 4, then CAL 01 on all 4?

b/ I might have to interrupt the sequence eg do CAL 01, CAL 02 on one day to all 4 and then resume at CAL 03 etc the next day.

Is Each CAL procedure is independent of the others, thus start CAL 01, complete and exit>>stored in NVRAM, proceed to CAL 02

OR must EVERY CAL 01-08 be done in order and finished before ALL are recorded in NVRAM?

Many thanks again!

Jon