Mesa 7i96S bad start
- Juxus
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05 Feb 2026 19:08 - 05 Feb 2026 19:11 #342498
by Juxus
Mesa 7i96S bad start was created by Juxus
Hi everyone,
I just started my first LinuxCNC project and unfortunately managed to damage my Mesa 7i96S right away. I accidentally applied about 10 V to the 5 V input for a few seconds. There was a little smoke, and now the board draws about 3 A at 5 V even with no external load connected.
Using a thermal camera, I identified a hot SMD component marked “KE 2E66B” located very close to the 5 V input connector (designator CR43 on the PCB). It heats up immediately when power is applied. Measuring across it shows about 0.6 ohm. From the package and marking it looks like it could be a polarized SMD capacitor (possibly tantalum), but I can’t determine the value or rating.
Can anyone tell me the specifications of this component, or point me to the correct replacement part? Is there a BOM or schematic available that lists its value?
Thanks a lot for your help.
I just started my first LinuxCNC project and unfortunately managed to damage my Mesa 7i96S right away. I accidentally applied about 10 V to the 5 V input for a few seconds. There was a little smoke, and now the board draws about 3 A at 5 V even with no external load connected.
Using a thermal camera, I identified a hot SMD component marked “KE 2E66B” located very close to the 5 V input connector (designator CR43 on the PCB). It heats up immediately when power is applied. Measuring across it shows about 0.6 ohm. From the package and marking it looks like it could be a polarized SMD capacitor (possibly tantalum), but I can’t determine the value or rating.
Can anyone tell me the specifications of this component, or point me to the correct replacement part? Is there a BOM or schematic available that lists its value?
Thanks a lot for your help.
Last edit: 05 Feb 2026 19:11 by Juxus.
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05 Feb 2026 19:35 - 05 Feb 2026 21:03 #342505
by PCW
Replied by PCW on topic Mesa 7i96S bad start
_usually_ CR343 will protect the rest of the card from overvoltages
CR43 is (or was) a SMBJ5V0 TVS diode across the 5V supply
CR43 is (or was) a SMBJ5V0 TVS diode across the 5V supply
Last edit: 05 Feb 2026 21:03 by PCW. Reason: wrong PN
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