7i97T stepgen outputs dead, encoders & I/O OK - suspect damaged P2 interface

“This header has a pin-out that matches a standard parallel port.”

This is true and it electrically matches  standard parallel port in terms of drive
and overvoltage capability.

PC parallel ports are also not suggested for direct connection to motor drives
where a single wiring mistake can permanently damage a motherboard.

It is possible to use the outputs of P2 directly (as you can with a PC parallel port)
but  care must be taken to avoid even an brief contact to a voltage  outside the safe range.

7i97t_5abobd is designed to interface to the common Sainsmart 5 Axis BOB:

www.amazon.com/SainSmart-Breakout-Board-...Driver/dp/B0093Y897A

As tommylight mentioned, eusurplus is a Mesa distributor and they currently have the 7I97T in stock.

Also as I mentioned, your damaged 7I97T is very likely repairable.

Thank you for your quick responses!  Please tell me, am I correct in understanding that U22 refers to this chip? Could you also tell me where else in Europe it can be found, or any suitable equivalents? 

Yes, U22

Here is at least one source:

eu.mouser.com/ProductDetail/Texas-Instru...gQLk2CaRciYmIQ%3D%3D
 

Thank you very much for your professional responses! I’ve decided to order another board along with a daughter card now to avoid a similar failure in the future. I’ll slowly work on repairing the current board, it will serve as a spare one, or I might sell it later. It seems that delivery across Europe will be quite fast using the link you provided. I’ll update you later on how my board recovery story ends.

While my new controller is on its way, could you tell me where I can find examples of electrical diagrams for connecting the board to peripheral devices (servo motors, encoders, sensors), especially in terms of their common ground? I don't want to make any mistakes again. Thanks!

Grounding is a really big subject but here a bit of advice

For standard step/dir drives with opto-isolated inputs, grounding is not
super important as there is little coupling from the drive to the step/dir lines

 It is important however  to keep encoder and step/dir lines away form any motor or power
lines to prevent unwanted coupling ( both inductive and capacitive ) from these noise
sources to the low voltage signal lines.

For encoder, analog, and step/dir lines to non opto isolated connections, a common ground
is vital between the 7I97T and the signal source/destinations. The exact wiring for the common ground
and reference to earth ground depends on the drive design. Typically motor drives will have an earth
ground but may have an isolated input or output common. If the drives have an isolated common input,
this should connect to the 7I97T GND and then be connected at one place to the earth ground.
 

Thank you for the contact of the Eusurplus store. They responded instantly at any time of day, shipped quickly, and everything arrived quite fast — from Portugal to Bulgaria in just one day! Although people in Bulgaria aren’t the fastest, and local delivery took another three days, that’s a minor thing — plus there were weekends — still much faster than waiting for a shipment from the U.S. I’ve connected everything, and it’s all working now. I got a 7i95 board to replace my 7i97, so I can connect the motors directly in stepper mode. Now all that’s left is fine-tuning the machine’s logic.