Mesa 7I76EU TB2 not working right (TB3 works fine) – need help diagnosing

PCW
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11 Apr 2026 20:21 #345426 by PCW

Replied by PCW on topic Mesa 7I76EU TB2 not working right (TB3 works fine) – need help diagnosing

Unless you changed the firmware, I doubt that that's the issue.
(all cards are tested and shipped with standard firmware)

The following user(s) said Thank You: adhamamer

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adhamamer
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21 Apr 2026 23:54 #345824 by adhamamer

Replied by adhamamer on topic Mesa 7I76EU TB2 not working right (TB3 works fine) – need help diagnosing

Update:

MESA Replied:“OK, examined the cardU15 (STEP+/DIR+ 0..3 driver) and RN31 (27 Ohm resistor networkin series with STEPO+/DIRO+ and STEPO-/DIRO- pins) were both damaged.RN31 had opens on the STEPO+ and DIRO+ pins.Damage was likely caused by connection of theSTEPO+,DIRO+ pinsto either something outside the 0 to +5V range (even briefly) ora long time short of the STEPO+,DIRO+ pins to 5V or ground.”

Im pretty confident that i did not cause this damage, all the wiring Ive done on tb2 was also done on tb3 to a standard tb6600 stepper driver
What do you guys think i should do?

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tommylight
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22 Apr 2026 00:27 #345826 by tommylight

Replied by tommylight on topic Mesa 7I76EU TB2 not working right (TB3 works fine) – need help diagnosing

adhamamer wrote:
Im pretty confident that i did not cause this damage, all the wiring Ive done on tb2 was also done on tb3 to a standard tb6600 stepper driver
What do you guys think i should do?

I have no idea what do you expect from us to tell you as i am sure you do not want to deal with reality.
My reality is: I have over 80 or 90 of Mesa boards in daily use, never ever had one fail nor had issues, ever, mostly on industrial machines in use 24/7/365.
P.S.
This is my polite answer as you said "im pretty confident...".
Next time try to figure out how that happened instead of insisting it did not happen.
Also, whatever the price of any Mesa board is, i have to pay at least twice that to get theme here, and i pay that gladly.

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PCW
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22 Apr 2026 02:16 #345827 by PCW

Replied by PCW on topic Mesa 7I76EU TB2 not working right (TB3 works fine) – need help diagnosing

Here's the thing, it may be difficult to tell what happened, but the card did not leave Mesa with
a blown 27 Ohm resistor network and a bad 74ACT541. Also, it is important to know what happened
so it does not happen again.

The good news is that the card is repairable. Mesa normally charges $35.00 for minor repairs like this.

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