Author Topic: Atten ADS1152CA trace issue  (Read 398 times)

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Offline NEELIMAVUNGAL

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Atten ADS1152CA trace issue
« on: October 21, 2019, 01:46:15 pm »
Hi all, i am new to this forum. I have an issue with my atten ads1152ca scope. I rarely used it. while working it suddeny stop tracing. then i did a self calibration but it stuck on calibrating channel 2. I suspect the probe and put a resister inside the bnc jack wth bare hand, but there is no noise trace. what could be the problem. any idea. please help me
 

Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #1 on: October 23, 2019, 06:30:16 pm »
 :( Nobody answered the question. look at the photos. I did not connected probes but the cursor is not in the middle position.
https://youtu.be/KqNTTcAdRTM
« Last Edit: October 23, 2019, 06:58:37 pm by NEELIMAVUNGAL »
 

Online tautech

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Re: Atten ADS1152CA trace issue
« Reply #2 on: October 23, 2019, 08:09:29 pm »
Try Default.
Then press V pos for each channel so to zero their positions.
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Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #3 on: October 24, 2019, 12:26:11 am »
Try Default.
Then press V pos for each channel so to zero their positions.
thank you for the comment. I have already tried even factory default. the result is same.
 

Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #4 on: October 24, 2019, 03:22:08 am »
I think this is a hardware issue. if so, what could be the problem, :-\
 

Online Microcheap

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Re: Atten ADS1152CA trace issue
« Reply #5 on: October 24, 2019, 04:16:06 am »
Is that a leaked electrolytic capacitor on your first picture? Try to probe the test points (TP) of the power supply rails to see if they are ok, normally there is a silk screen on the board close to the TP with the nominal value.
 

Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #6 on: October 24, 2019, 07:05:50 am »
Is that a leaked electrolytic capacitor on your first picture? Try to probe the test points (TP) of the power supply rails to see if they are ok, normally there is a silk screen on the board close to the TP with the nominal value.
Thank you sir, that is not a leaky capacitor.but is gum on it. and there is no voltage values on silkscreen. but I tested all the test points according to the service Manuel of a similar sigilent board and the TP voltages are OK.
 

Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #7 on: October 24, 2019, 07:16:31 am »
Actually I have tested all the power rails and capacitors including bypass capacitors of each power rail. I do not know the signal input mechanism of a dso. there is an ad8370 variable gain amp in the signal input circuit. if you know more about the functions and voltage values of that chip, please help me.I have referred the datasheet but not fully understood.
 
 

Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #8 on: October 24, 2019, 08:16:59 am »
Look at the voltages. is this normal :-\
 

Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #9 on: October 25, 2019, 03:13:10 pm »
Hello all, please see the picture what is that marked chip 6552. Is that op amp or mosfet. please  help.
 

Offline mikerj

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Re: Atten ADS1152CA trace issue
« Reply #10 on: October 25, 2019, 07:37:02 pm »
Possibly an LMH6552, a high bandwidth differential amplifier.
 

Offline Kleinstein

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Re: Atten ADS1152CA trace issue
« Reply #11 on: October 25, 2019, 10:32:44 pm »
Unless the trace is really out and can not be shifted back (with y-position) I don't think this is really an HW issue. It looks more like lost adjustment data. Normally there should be a software way to readjust the zero position.
 

Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #12 on: October 26, 2019, 01:00:43 am »
Possibly an LMH6552, a high bandwidth differential amplifier.
Thanks, let me try to find out.
 

Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #13 on: October 26, 2019, 01:03:15 am »
Unless the trace is really out and can not be shifted back (with y-position) I don't think this is really an HW issue. It looks more like lost adjustment data. Normally there should be a software way to readjust the zero position.
thanks for the replay, It is not only a trace positioning issue, but I can not trace except in 500 mv division on both channels!
 

Online tautech

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Re: Atten ADS1152CA trace issue
« Reply #14 on: October 26, 2019, 01:12:02 am »
but I can not trace except in 500 mv division on both channels!
Ah, so we finally have a good symptom.

The V/div attenuation settings are made in the front end input stages.
So you need follow the signal input path near the BNC's here:



Do any relays click when adjusting V/div ?
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Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #15 on: October 26, 2019, 04:31:38 am »

Do any relays click when adjusting V/div ?
yes, I can hear clicking relays while changing vertical pitch.
I noticed some voltage difference in two input stages and the source of the difference is from the chip 6552.
« Last Edit: October 26, 2019, 04:47:27 am by NEELIMAVUNGAL »
 

Offline Kleinstein

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Re: Atten ADS1152CA trace issue
« Reply #16 on: October 26, 2019, 07:42:04 am »
With both channels faulty, and still working at some gain setting, I would suspect something like a supply or control signal (e.g. some HC4094 or HC595 chip or a small DAC to control VCAs) to the variable gain part.

What happens with the non working gain setting ?  There is a difference between always reading zero, just not signal but still Y-pos working and just a wrong possibly way to small or or large amplitude. 
 

Offline NEELIMAVUNGAL

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Re: Atten ADS1152CA trace issue
« Reply #17 on: October 26, 2019, 11:37:58 am »
With both channels faulty, and still working at some gain setting, I would suspect something like a supply or control signal (e.g. some HC4094 or HC595 chip or a small DAC to control VCAs) to the variable gain part.

What happens with the non working gain setting ?  There is a difference between always reading zero, just not signal but still Y-pos working and just a wrong possibly way to small or or large amplitude.
Thank you, please see this video https://youtu.be/KqNTTcAdRTM and ask me for further clarification of the status.
 


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