|
I posted a few months ago on this scope.
I was not able to get this resolved at the time and got busy on other projects.
I want to take a fresh look at it now.
Here is an example of what I am seeing.
Using a function generator with 50 ohm termination, frequency set to .5 MHz, volts 4.0 peak to peak- out of the function generator.
If sending a square wave the scope will auto measure the voltages corectly.
Example;
peak to peak 2.02 volts
pos peak 1.01
neg peak 1.01
If I change to a triang. wave. (frequency and voltage the same) the scope will now not measure the voltages correctly.
Eample;
peak to peak 1.1 volts
pos peak .97 volts
neg peak .14 volts
If I measure manually using the cursers, they are correct.
I verified the trigger cal. and did a DC balance.
Please help.
Thanks, B
|
Any ideas?
B
toggle quoted message
Show quoted text
--- In TekScopes@..., "andersen_bill@..." <andersen_bill@...> wrote:
I posted a few months ago on this scope.
I was not able to get this resolved at the time and got busy on other projects.
I want to take a fresh look at it now.
Here is an example of what I am seeing.
Using a function generator with 50 ohm termination, frequency set to .5 MHz, volts 4.0 peak to peak- out of the function generator.
If sending a square wave the scope will auto measure the voltages corectly.
Example;
peak to peak 2.02 volts
pos peak 1.01
neg peak 1.01
If I change to a triang. wave. (frequency and voltage the same) the scope will now not measure the voltages correctly.
Eample;
peak to peak 1.1 volts
pos peak .97 volts
neg peak .14 volts
If I measure manually using the cursers, they are correct.
I verified the trigger cal. and did a DC balance.
Please help.
Thanks, B
|
Did you try to?re-do the vertical calibration? Can you look at the
waveform during the measurement process to see if it is loading the input
down?
?
?
Strange one. Hope you find it.
?
Tom
?
toggle quoted message
Show quoted text
----- Original Message -----
Sent: Wednesday, January 02, 2013 6:58
PM
Subject: [TekScopes] Re: 2465B auto
measurment error
?
Any ideas?
B
--- In TekScopes@...,
"andersen_bill@..." wrote:
>
> I posted
a few months ago on this scope.
>
> I was not able to get this
resolved at the time and got busy on other projects.
>
> I want
to take a fresh look at it now.
>
> Here is an example of what I
am seeing.
>
> Using a function generator with 50 ohm
termination, frequency set to .5 MHz, volts 4.0 peak to peak- out of the
function generator.
>
> If sending a square wave the scope will
auto measure the voltages corectly.
>
> Example;
>
>
peak to peak 2.02 volts
> pos peak 1.01
> neg peak 1.01
>
> If I change to a triang. wave. (frequency and voltage the same) the
scope will now not measure the voltages correctly.
>
>
Eample;
>
> peak to peak 1.1 volts
> pos peak .97
volts
> neg peak .14 volts
>
> If I measure manually using
the cursers, they are correct.
>
> I verified the trigger cal.
and did a DC balance.
>
> Please help.
>
> Thanks,
B
>
|
Doesn't it use the trigger functions to do the auto voltage measurements ? I thought it just adjusted the trigger voltage up and down until it found the peaks of where it could trigger and then just reported that back.
Jeff
toggle quoted message
Show quoted text
On 1/2/2013 5:18 PM, Tom Miller wrote:
Did you try to re-do the vertical calibration? Can you look at the waveform during the measurement process to see if it is loading the input down?
Strange one. Hope you find it.
Tom
----- Original Message -----
*From:* andersen_bill@...
<mailto:andersen_bill@...>
*To:* TekScopes@... <mailto:TekScopes@...>
*Sent:* Wednesday, January 02, 2013 6:58 PM
*Subject:* [TekScopes] Re: 2465B auto measurment error
Any ideas?
B
--- In TekScopes@...
<mailto:TekScopes@...>, "andersen_bill@..."
<andersen_bill@...> wrote:
>
> I posted a few months ago on this scope.
>
> I was not able to get this resolved at the time and got busy on
other projects.
>
> I want to take a fresh look at it now.
>
> Here is an example of what I am seeing.
>
> Using a function generator with 50 ohm termination, frequency
set to .5 MHz, volts 4.0 peak to peak- out of the function generator.
>
> If sending a square wave the scope will auto measure the
voltages corectly.
>
> Example;
>
> peak to peak 2.02 volts
> pos peak 1.01
> neg peak 1.01
>
> If I change to a triang. wave. (frequency and voltage the same)
the scope will now not measure the voltages correctly.
>
> Eample;
>
> peak to peak 1.1 volts
> pos peak .97 volts
> neg peak .14 volts
>
> If I measure manually using the cursers, they are correct.
>
> I verified the trigger cal. and did a DC balance.
>
> Please help.
>
> Thanks, B
>
|
That is how I remember it but it might be worth going through the theory section in the service manual to confirm it. The automatic peak to peak trigger level is set to the average of the positive and negative peak. If the 2465B can display the trigger level as I know my 2247A can, does that change depending on the waveform? I skimmed through the 2465B service manual and I do not see how it finds the peaks. On Wed, 02 Jan 2013 18:30:29 -0700, Jeff Machesky <jeff@...> wrote: Doesn't it use the trigger functions to do the auto voltage measurements
? I thought it just adjusted the trigger voltage up and down until it
found the peaks of where it could trigger and then just reported that back.
Jeff
On 1/2/2013 5:18 PM, Tom Miller wrote:
Did you try to re-do the vertical calibration? Can you look at the
waveform during the measurement process to see if it is loading the
input down?
Strange one. Hope you find it.
Tom
----- Original Message -----
*From:* andersen_bill@...
<mailto:andersen_bill@...>
*To:* TekScopes@... <mailto:TekScopes@...>
*Sent:* Wednesday, January 02, 2013 6:58 PM
*Subject:* [TekScopes] Re: 2465B auto measurment error
Any ideas?
B
--- In TekScopes@...
<mailto:TekScopes@...>, "andersen_bill@..."
<andersen_bill@...> wrote:
>
> I posted a few months ago on this scope.
>
> I was not able to get this resolved at the time and got busy on
other projects.
>
> I want to take a fresh look at it now.
>
> Here is an example of what I am seeing.
>
> Using a function generator with 50 ohm termination, frequency
set to .5 MHz, volts 4.0 peak to peak- out of the function generator.
>
> If sending a square wave the scope will auto measure the
voltages corectly.
>
> Example;
>
> peak to peak 2.02 volts
> pos peak 1.01
> neg peak 1.01
>
> If I change to a triang. wave. (frequency and voltage the same)
the scope will now not measure the voltages correctly.
>
> Eample;
>
> peak to peak 1.1 volts
> pos peak .97 volts
> neg peak .14 volts
>
> If I measure manually using the cursers, they are correct.
>
> I verified the trigger cal. and did a DC balance.
>
> Please help.
>
> Thanks, B
|
Yes, I believe that is correct. Maybe pull the U500 and clean the contacts carefully?
Does it do the same for all the channels?
Do you have or can get a spare U500?
Tom
toggle quoted message
Show quoted text
----- Original Message ----- From: "Jeff Machesky" <jeff@...> To: <TekScopes@...> Sent: Wednesday, January 02, 2013 8:30 PM Subject: Re: [TekScopes] Re: 2465B auto measurment error Doesn't it use the trigger functions to do the auto voltage measurements
? I thought it just adjusted the trigger voltage up and down until it
found the peaks of where it could trigger and then just reported that back.
Jeff
On 1/2/2013 5:18 PM, Tom Miller wrote:
Did you try to re-do the vertical calibration? Can you look at the
waveform during the measurement process to see if it is loading the
input down?
Strange one. Hope you find it.
Tom
----- Original Message -----
*From:* andersen_bill@...
<mailto:andersen_bill@...>
*To:* TekScopes@... <mailto:TekScopes@...>
*Sent:* Wednesday, January 02, 2013 6:58 PM
*Subject:* [TekScopes] Re: 2465B auto measurment error
Any ideas?
B
--- In TekScopes@...
<mailto:TekScopes@...>, "andersen_bill@..."
<andersen_bill@...> wrote:
>
> I posted a few months ago on this scope.
>
> I was not able to get this resolved at the time and got busy on
other projects.
>
> I want to take a fresh look at it now.
>
> Here is an example of what I am seeing.
>
> Using a function generator with 50 ohm termination, frequency
set to .5 MHz, volts 4.0 peak to peak- out of the function generator.
>
> If sending a square wave the scope will auto measure the
voltages corectly.
>
> Example;
>
> peak to peak 2.02 volts
> pos peak 1.01
> neg peak 1.01
>
> If I change to a triang. wave. (frequency and voltage the same)
the scope will now not measure the voltages correctly.
>
> Eample;
>
> peak to peak 1.1 volts
> pos peak .97 volts
> neg peak .14 volts
>
> If I measure manually using the cursers, they are correct.
>
> I verified the trigger cal. and did a DC balance.
>
> Please help.
>
> Thanks, B
>
------------------------------------
Yahoo! Groups Links
|
I would adjust the trigger and see if it can reach the very edges of a sine wave. If it stops triggering before the peaks then something is out of calibration or hopefully not busted. Mine is off a little bit, but it's off by the same amount that my mentioned test shows. It almost triggers to the peaks..but not right to the edge. So my calculated reading is a bit low. In my case I just need to rerun the trigger calibration and do a bit better job. The Para-metrics are based on the trigger from what I've read and then also have their own calibration for frequency.
Jeff
toggle quoted message
Show quoted text
On 1/2/2013 7:17 PM, Tom Miller wrote:
Yes, I believe that is correct. Maybe pull the U500 and clean the contacts
carefully?
Does it do the same for all the channels?
Do you have or can get a spare U500?
Tom
----- Original Message -----
From: "Jeff Machesky" <jeff@... <mailto:jeff%40codebest.com>>
To: <TekScopes@... <mailto:TekScopes%40yahoogroups.com>>
Sent: Wednesday, January 02, 2013 8:30 PM
Subject: Re: [TekScopes] Re: 2465B auto measurment error
Doesn't it use the trigger functions to do the auto voltage measurements
? I thought it just adjusted the trigger voltage up and down until it
found the peaks of where it could trigger and then just reported that
back.
Jeff
On 1/2/2013 5:18 PM, Tom Miller wrote:
Did you try to re-do the vertical calibration? Can you look at the
waveform during the measurement process to see if it is loading the
input down?
Strange one. Hope you find it.
Tom
----- Original Message -----
*From:* andersen_bill@...
<mailto:andersen_bill%40rocketmail.com>
<mailto:andersen_bill@...
<mailto:andersen_bill%40rocketmail.com>>
*To:* TekScopes@...
<mailto:TekScopes%40yahoogroups.com> <mailto:TekScopes@... <mailto:TekScopes%40yahoogroups.com>>
*Sent:* Wednesday, January 02, 2013 6:58 PM
*Subject:* [TekScopes] Re: 2465B auto measurment error
Any ideas?
B
--- In TekScopes@... <mailto:TekScopes%40yahoogroups.com>
<mailto:TekScopes@...
<mailto:TekScopes%40yahoogroups.com>>, "andersen_bill@..."
<andersen_bill@...> wrote:
I posted a few months ago on this scope.
I was not able to get this resolved at the time and got busy on
other projects.
I want to take a fresh look at it now.
Here is an example of what I am seeing.
Using a function generator with 50 ohm termination, frequency
set to .5 MHz, volts 4.0 peak to peak- out of the function generator.
If sending a square wave the scope will auto measure the
voltages corectly.
Example;
peak to peak 2.02 volts
pos peak 1.01
neg peak 1.01
If I change to a triang. wave. (frequency and voltage the same)
the scope will now not measure the voltages correctly.
Eample;
peak to peak 1.1 volts
pos peak .97 volts
neg peak .14 volts
If I measure manually using the cursers, they are correct.
I verified the trigger cal. and did a DC balance.
Please help.
Thanks, B
------------------------------------
Yahoo! Groups Links
|
The SM lists A "standard amplitude signal generator" for setting the triggers.
I have been using a function gen set to 60Hz with a sign wave. The cal accepts the input and the triggers appear to bet set correctly when the trigger is manually adjusted.
Is there a specific frequency and or type of signal required for the the trigger cal?
B
toggle quoted message
Show quoted text
--- In TekScopes@..., Jeff Machesky wrote:
I would adjust the trigger and see if it can reach the very edges of a
sine wave. If it stops triggering before the peaks then something is out
of calibration or hopefully not busted. Mine is off a little bit, but
it's off by the same amount that my mentioned test shows. It almost
triggers to the peaks..but not right to the edge. So my calculated
reading is a bit low. In my case I just need to rerun the trigger
calibration and do a bit better job. The Para-metrics are based on the
trigger from what I've read and then also have their own calibration for
frequency.
Jeff
On 1/2/2013 7:17 PM, Tom Miller wrote:
Yes, I believe that is correct. Maybe pull the U500 and clean the
contacts
carefully?
Does it do the same for all the channels?
Do you have or can get a spare U500?
Tom
----- Original Message -----
From: "Jeff Machesky" >
To: >
Sent: Wednesday, January 02, 2013 8:30 PM
Subject: Re: [TekScopes] Re: 2465B auto measurment error
Doesn't it use the trigger functions to do the auto voltage measurements
? I thought it just adjusted the trigger voltage up and down until it
found the peaks of where it could trigger and then just reported that
back.
Jeff
On 1/2/2013 5:18 PM, Tom Miller wrote:
Did you try to re-do the vertical calibration? Can you look at the
waveform during the measurement process to see if it is loading the
input down?
Strange one. Hope you find it.
Tom
----- Original Message -----
*From:* andersen_bill@...
> > *To:* TekScopes@...
> > *Sent:* Wednesday, January 02, 2013 6:58 PM
*Subject:* [TekScopes] Re: 2465B auto measurment error
Any ideas?
B
--- In TekScopes@...
> >, "andersen_bill@" wrote:
I posted a few months ago on this scope.
I was not able to get this resolved at the time and got busy on
other projects.
I want to take a fresh look at it now.
Here is an example of what I am seeing.
Using a function generator with 50 ohm termination, frequency
set to .5 MHz, volts 4.0 peak to peak- out of the function generator.
If sending a square wave the scope will auto measure the
voltages corectly.
Example;
peak to peak 2.02 volts
pos peak 1.01
neg peak 1.01
If I change to a triang. wave. (frequency and voltage the same)
the scope will now not measure the voltages correctly.
Eample;
peak to peak 1.1 volts
pos peak .97 volts
neg peak .14 volts
If I measure manually using the cursers, they are correct.
I verified the trigger cal. and did a DC balance.
Please help.
Thanks, B
------------------------------------
Yahoo! Groups Links
|
Yes, it is a 1 kHz square wave at 0.5 volts PP if I remember right. I use
the CG-5011 to do mine.
?
Ok, looking at the procedure, it wants 0.5 VPP @ 1kHz and 2 VPP @1 kHz.
Both square wave.
See the Cal-03 section.
?
Tom
?
?
?
?
toggle quoted message
Show quoted text
----- Original Message -----
Sent: Thursday, January 03, 2013 12:01
PM
Subject: [TekScopes] Re: 2465B auto
measurment error
?
The SM lists A "standard amplitude signal generator" for setting the
triggers.
I have been using a function gen set to 60Hz with a sign
wave. The cal accepts the input and the triggers appear to bet set correctly
when the trigger is manually adjusted.
Is there a specific frequency
and or type of signal required for the the trigger cal?
B
--- In
TekScopes@...,
Jeff Machesky wrote:
>
> I would adjust the trigger and see if it
can reach the very edges of a
> sine wave. If it stops triggering
before the peaks then something is out
> of calibration or hopefully
not busted. Mine is off a little bit, but
> it's off by the same amount
that my mentioned test shows. It almost
> triggers to the peaks..but
not right to the edge. So my calculated
> reading is a bit low. In my
case I just need to rerun the trigger
> calibration and do a bit better
job. The Para-metrics are based on the
> trigger from what I've read
and then also have their own calibration for
> frequency.
>
> Jeff
>
> On 1/2/2013 7:17 PM, Tom Miller wrote:
>
>
> > Yes, I believe that is correct. Maybe pull the U500 and
clean the
> > contacts
> > carefully?
> >
>
> Does it do the same for all the channels?
> >
> > Do
you have or can get a spare U500?
> >
> > Tom
>
>
> > ----- Original Message -----
> > From: "Jeff
Machesky" >
> > To: >
> > Sent: Wednesday, January 02,
2013 8:30 PM
> > Subject: Re: [TekScopes] Re: 2465B auto measurment
error
> >
> > > Doesn't it use the trigger functions to
do the auto voltage measurements
> > > ? I thought it just
adjusted the trigger voltage up and down until it
> > > found the
peaks of where it could trigger and then just reported that
> > >
back.
> > >
> > > Jeff
> > >
> >
> On 1/2/2013 5:18 PM, Tom Miller wrote:
> > >>
> >
>> Did you try to re-do the vertical calibration? Can you look at
the
> > >> waveform during the measurement process to see if it
is loading the
> > >> input down?
> > >> Strange
one. Hope you find it.
> > >> Tom
> > >>
>
> >> ----- Original Message -----
> > >> *From:*
andersen_bill@...
> >
> > >>
> >
>
> >> *To:* TekScopes@...
> >
> >
> > >> *Sent:* Wednesday, January
02, 2013 6:58 PM
> > >> *Subject:* [TekScopes] Re: 2465B auto
measurment error
> > >>
> > >>
> >
>> Any ideas?
> > >>
> > >> B
> >
>> --- In TekScopes@...
> > >>
> >, "andersen_bill@"
> > >>
wrote:
> > >> >
> > >> > I posted a few
months ago on this scope.
> > >> >
> > >>
> I was not able to get this resolved at the time and got busy on
>
> >> other projects.
> > >> >
> > >>
> I want to take a fresh look at it now.
> > >> >
>
> >> > Here is an example of what I am seeing.
> >
>> >
> > >> > Using a function generator with 50
ohm termination, frequency
> > >> set to .5 MHz, volts 4.0 peak
to peak- out of the function generator.
> > >> >
>
> >> > If sending a square wave the scope will auto measure
the
> > >> voltages corectly.
> > >>
>
> > >> > Example;
> > >> >
>
> >> > peak to peak 2.02 volts
> > >> > pos peak
1.01
> > >> > neg peak 1.01
> > >>
>
> > >> > If I change to a triang. wave. (frequency and
voltage the same)
> > >> the scope will now not measure the
voltages correctly.
> > >> >
> > >> >
Eample;
> > >> >
> > >> > peak to peak 1.1
volts
> > >> > pos peak .97 volts
> > >> >
neg peak .14 volts
> > >> >
> > >> > If I
measure manually using the cursers, they are correct.
> > >>
>
> > >> > I verified the trigger cal. and did a DC
balance.
> > >> >
> > >> > Please
help.
> > >> >
> > >> > Thanks, B
>
> >> >
> > >>
> > >>
> >
>
> > >
> > >
> > >
------------------------------------
> > >
> > >
Yahoo! Groups Links
> > >
> > >
> >
>
> >
> >
>
|
Thanksfor all of your input.
I redid the cal 2 and 3. Vertical and triggers.
Error is still there. Looks like at low frequencies-below .5 MHZ it works, above that the error occurs.
I am thinking there is a problem with the U500 trigger.
I see a few on Ebay. Anyone here have one for sale?
B
toggle quoted message
Show quoted text
--- In TekScopes@..., "Tom Miller" wrote:
Yes, it is a 1 kHz square wave at 0.5 volts PP if I remember right. I use the CG-5011 to do mine.
Ok, looking at the procedure, it wants 0.5 VPP @ 1kHz and 2 VPP @1 kHz. Both square wave.
See the Cal-03 section.
Tom
----- Original Message -----
From: andersen_bill@...
To: TekScopes@...
Sent: Thursday, January 03, 2013 12:01 PM
Subject: [TekScopes] Re: 2465B auto measurment error
The SM lists A "standard amplitude signal generator" for setting the triggers.
I have been using a function gen set to 60Hz with a sign wave. The cal accepts the input and the triggers appear to bet set correctly when the trigger is manually adjusted.
Is there a specific frequency and or type of signal required for the the trigger cal?
B
--- In TekScopes@..., Jeff Machesky wrote:
>
> I would adjust the trigger and see if it can reach the very edges of a
> sine wave. If it stops triggering before the peaks then something is out
> of calibration or hopefully not busted. Mine is off a little bit, but
> it's off by the same amount that my mentioned test shows. It almost
> triggers to the peaks..but not right to the edge. So my calculated
> reading is a bit low. In my case I just need to rerun the trigger
> calibration and do a bit better job. The Para-metrics are based on the
> trigger from what I've read and then also have their own calibration for
> frequency.
>
> Jeff
>
> On 1/2/2013 7:17 PM, Tom Miller wrote:
> >
> > Yes, I believe that is correct. Maybe pull the U500 and clean the
> > contacts
> > carefully?
> >
> > Does it do the same for all the channels?
> >
> > Do you have or can get a spare U500?
> >
> > Tom
> >
> > ----- Original Message -----
> > From: "Jeff Machesky" >
> > To: >
> > Sent: Wednesday, January 02, 2013 8:30 PM
> > Subject: Re: [TekScopes] Re: 2465B auto measurment error
> >
> > > Doesn't it use the trigger functions to do the auto voltage measurements
> > > ? I thought it just adjusted the trigger voltage up and down until it
> > > found the peaks of where it could trigger and then just reported that
> > > back.
> > >
> > > Jeff
> > >
> > > On 1/2/2013 5:18 PM, Tom Miller wrote:
> > >>
> > >> Did you try to re-do the vertical calibration? Can you look at the
> > >> waveform during the measurement process to see if it is loading the
> > >> input down?
> > >> Strange one. Hope you find it.
> > >> Tom
> > >>
> > >> ----- Original Message -----
> > >> *From:* andersen_bill@
> >
> > >>
> >
> > >> *To:* TekScopes@...
> >
> >
> > >> *Sent:* Wednesday, January 02, 2013 6:58 PM
> > >> *Subject:* [TekScopes] Re: 2465B auto measurment error
> > >>
> > >>
> > >> Any ideas?
> > >>
> > >> B
> > >> --- In TekScopes@...
> > >>
> >, "andersen_bill@"
> > >> wrote:
> > >> >
> > >> > I posted a few months ago on this scope.
> > >> >
> > >> > I was not able to get this resolved at the time and got busy on
> > >> other projects.
> > >> >
> > >> > I want to take a fresh look at it now.
> > >> >
> > >> > Here is an example of what I am seeing.
> > >> >
> > >> > Using a function generator with 50 ohm termination, frequency
> > >> set to .5 MHz, volts 4.0 peak to peak- out of the function generator.
> > >> >
> > >> > If sending a square wave the scope will auto measure the
> > >> voltages corectly.
> > >> >
> > >> > Example;
> > >> >
> > >> > peak to peak 2.02 volts
> > >> > pos peak 1.01
> > >> > neg peak 1.01
> > >> >
> > >> > If I change to a triang. wave. (frequency and voltage the same)
> > >> the scope will now not measure the voltages correctly.
> > >> >
> > >> > Eample;
> > >> >
> > >> > peak to peak 1.1 volts
> > >> > pos peak .97 volts
> > >> > neg peak .14 volts
> > >> >
> > >> > If I measure manually using the cursers, they are correct.
> > >> >
> > >> > I verified the trigger cal. and did a DC balance.
> > >> >
> > >> > Please help.
> > >> >
> > >> > Thanks, B
> > >> >
> > >>
> > >>
> > >
> > >
> > >
> > > ------------------------------------
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> >
> >
>
|
David Hess