Hello!

I have got a Tek 2465B which displays this error on startup:

TEST 04 FAIL 11

PUSH A/B TTRIG TO EXIT

From the Service Manual, it seems a calibration data error. Does it
mean there is some faulty non-volatile RAM?. If so, is it replaceable
with a current type?. Any hint to fix this?

Thanks for any help!

Regards,

JOSE
http://jvgavila.com

JVG wrote in news:7f72d417-7e7c-4d2e-95d3-
:

Hello!

I have got a Tek 2465B which displays this error on startup:

TEST 04 FAIL 11

PUSH A/B TTRIG TO EXIT

From the Service Manual, it seems a calibration data error. Does it
mean there is some faulty non-volatile RAM?. If so, is it replaceable
with a current type?. Any hint to fix this?

Thanks for any help!

Regards,

JOSE
http://jvgavila.com


there's an IC called a NVRAM that stores the cal constants,and it fails
often enough. you have to re-cal the scope after replacement.
I have no idea if there's a modern substitute with a longer life.

--
Jim Yanik
jyanik
at
kua.net

Hello Jim,

Thanks for your answer!

On Dec 17, 11:28 pm, Jim Yanik wrote:
there's an IC called a NVRAM that stores the cal constants,and it fails
often enough. you have to re-cal the scope after replacement.
I have no idea if there's a modern substitute with a longer life.

OK, I have found there are still some compatible ICs I can use (as the
Dallas DS-1225AB-70)

Now, next problem... calibration. What equipment would I need to do
it?

Regards,

JOSE
http://jvgavila.com

"JVG" wrote in message
...
Hello!

I have got a Tek 2465B which displays this error on startup:

TEST 04 FAIL 11

PUSH A/B TTRIG TO EXIT

From the Service Manual, it seems a calibration data error. Does it
mean there is some faulty non-volatile RAM?. If so, is it replaceable
with a current type?. Any hint to fix this?

I have very recently repaired my 2465B and successfully replaced the lithium
battery with a pair of AA's in a battery holder stuck to the PCB with some
double-sided foam adhesive tape. I used decent AA's (Duracell Ultra) in an
attempt to reduce risk of leakage.

Recalibration takes quite some time afterwards, so be prepared!

Cheers, Howard

Hello Howard,

Thanks for your message!

On Dec 18, 11:01 am, "Howard Long" wrote:
I have very recently repaired my 2465B and successfully replaced the lithium
battery with a pair of AA's in a battery holder stuck to the PCB with some
double-sided foam adhesive tape. I used decent AA's (Duracell Ultra) in an
attempt to reduce risk of leakage.

Recalibration takes quite some time afterwards, so be prepared!

Could you elaborate a bit about that?. Which equipment is needed?. I
have a good lab at home but perhaps not for calibration purposes.

Best regards,

JOSE
http://jvgavila.com

"JVG" wrote in message
...
Hello Howard,

Thanks for your message!

On Dec 18, 11:01 am, "Howard Long" wrote:
I have very recently repaired my 2465B and successfully replaced the
lithium
battery with a pair of AA's in a battery holder stuck to the PCB with
some
double-sided foam adhesive tape. I used decent AA's (Duracell Ultra) in
an
attempt to reduce risk of leakage.

Recalibration takes quite some time afterwards, so be prepared!

Could you elaborate a bit about that?. Which equipment is needed?. I
have a good lab at home but perhaps not for calibration purposes.


The cal procedure, including the equipment needed is in the service manual.
They discuss the use of a pulse/mark generator, although I used a standard
signal generator with a variable duty cycle and a couple of attenuators for
2MHz and less, and an RF sig gen for the small number of higher frequency
measurements: maybe not the most accurate, but with careful use you can
still do a pretty good cal. The levels were calibrated with another 'scope
in circuit.

The service manual is available at http://bama.sbc.edu/.

One tiny correction - I actually used AAA's not AA's.

Cheers, Howard

Hi Howard,

Thanks a lot for your detailed message!. Yes, I will look at the
Service Manual (had it downloaded but was curious to know if it could
be done with the equipment I have... it seems so :-) )

On Dec 18, 1:50 pm, "Howard Long" wrote:
The cal procedure, including the equipment needed is in the service manual.
They discuss the use of a pulse/mark generator, although I used a standard
signal generator with a variable duty cycle and a couple of attenuators for
2MHz and less, and an RF sig gen for the small number of higher frequency
measurements: maybe not the most accurate, but with careful use you can
still do a pretty good cal. The levels were calibrated with another 'scope
in circuit.

One further question... when scope is uncalibrated, does it show a
trace?. On mine, I get only text display with ??? after it.

What I get after the error display and pressing "A/B Trig" is more or
less:

Volt/division ????? SEC/DIV ?????

But no trace... is this usual?

Thanks!

JOSE
http://jvgavila.com

"JVG" wrote in message
...

One further question... when scope is uncalibrated, does it show a
trace?. On mine, I get only text display with ??? after it.

What I get after the error display and pressing "A/B Trig" is more or
less:

Volt/division ????? SEC/DIV ?????

But no trace... is this usual?

Losing the trace was exactly what mine did until I replaced the batteries
and re-cal'd it.

First check it's triggering - the TRIG'D LED should be on.

Your channel (eg, CH1) should be selected.

Try adjusting INTENSITY and the vertical POSITION for your channel.

If no luck, push the BEAM FIND.

If still no luck, press STEP/AUTO.

Still no luck?

Do a DC balance by pushing the upper and lower input coupling buttons for
your channel simultaneously (P4-3 in the operator's manual)., then repeat
the above.

I used to have to go through this each time I switched it on before
replacing the battery and re-cal'ing.

I still have the ?????? on the lower display I believe because I have not
managed to complete the calibration for the option 06 counter timer trigger
module I have installed in my 'scope. I have left the 'scope in CAL mode, so
that the "?????" become less annoying "......" instead for now until I can
figure out the cal procedure for the CT option.

Cheers, Howard