Mesa 7i76e in trouble. NVC7608 fried.

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27 Dec 2019 17:07 - 27 Dec 2019 17:10 #153294 by abu
Hi everyone.
This time I come with a hardware problem.
20 days ago, a friend bought a Mesa 7i76e. He asked me about installation information.
Well, he got the instruction manual from mesanet.com but I recommended this thread ...
forum.linuxcnc.org/27-driver-boards/3191...ection-sheet?start=0
In Norbert's work we can see this scheme.

File Attachment:


My friend copied it with an adjustable laboratory power source (24 v).
The board did its own smoke test. The NVC7608 (U5) chip was fried.
Later, my friend connected the board with TB3 and network cable only. Linux recognized 7i76e but LinuxCNC crashes after config. I add this information in case it is helpful.

Any experience or comment about this incident?

Thanks
Last edit: 27 Dec 2019 17:10 by abu.

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27 Dec 2019 17:34 - 27 Dec 2019 17:35 #153295 by PCW
We have had a higher number of NCV7608 failures than normal in the last 7I76E lot
These failures can be caused by miss-application (over-voltage, switching the DC
field power side, using unfiltered supplies etc) But in this case I am beginning to suspect
that there may be a production lot of NCV7608 chips that have a issue of some kind. We
have had about 7 failures in 400 cards which is quite high. There were no failures in field I/O
production loopback testing at 30VDC and 500 ma so its still a bit surprising but we
will do warranty repair/replacement of any failed cards where there is no obvious miss-application.
Last edit: 27 Dec 2019 17:35 by PCW.

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27 Dec 2019 18:15 #153297 by abu
Thank, Peter
I have news from my friend. I see that the solution is planned.

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18 Apr 2020 10:43 #164439 by Yannis
Hi
I experience the same problem
where can i find this item to replace it?
my location is Greece
I purchase the 7i76e fro EU SURPLUS

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18 Apr 2020 20:34 - 18 Apr 2020 20:34 #164507 by PCW
The complete part number is NCV7608DWR2G.

You should make sure that you are not switching the field power on the DC side of the 7I76E
As this _will_ damage the driver chips. The other thing that can damage the driver chips is
switching large inductive loads (greater than 60 mA or so) without a flyback diode. If you
have done neither of these things, and the board is less than 2 years old it is covered
under warranty.
Last edit: 18 Apr 2020 20:34 by PCW.

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21 Apr 2020 05:25 #164927 by Yannis
Hello
i never hook the 7i76 with the machine
still trying to find the connection for the servo drivers
I send the required data to EU SURPLUS the re seller of the card
and waiting instructions from them
Regards

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21 Apr 2020 15:24 #164971 by PCW
EU Surplus should be able to replace it for you
The following user(s) said Thank You: Yannis

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17 Nov 2021 10:47 #226727 by Raban
hi !
i Have the same problem :
The card after working properly for about 4 months now has a problem with the outputs ( out 7 and out 6 TB6) .
The two outputs do not work and the area near the out0-out7 outputs is overheated .
The problem appeared during normal processing .
Now the two outputs do not work, even without load all the axis control part works correctly .
The board is powered by a single omron 24 vdc industrial switching power supply, between the power supply and the board there are no disconnectors or relays The two outputs drive 2 24v dc relays with a coil that absorbs 40mA protected by a free wheeling diode .
I think it is a problem on the output stage.


Everything works then except the outputs on tb6.
Do you think it is possible to disable that ic to prevent it from overheating and use the outputs on tb5?

Eusurplus replied that it has no cards available and sent me directly to MESA ...
Now I await response from MESA ...
Is it possible to make some diagnoses via software?

In your opinion, just replace the NCV7608 chip?

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17 Nov 2021 15:02 #226742 by PCW
Yes, you can replace the NCV7608 chip, but Mesa will replace the card under warranty

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06 Dec 2021 15:10 #228438 by Raban
The new card (warranty replacement) arrived today.
Are there any further precautions to prevent the output stage from breaking again?
For example a transistor to drive the load, or an SSR?

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