No steps Mesa 7i76e

By static voltage I mean what is read by a voltmeter
when LinuxCNC is not running

Between pin 1 and 6 Ground and 5v+ i have 5.02v. 2-3 Step+ and Step- 0v, 3-4 Dir- Dir+0v. I also did a voltage drop from pin 6-5 5.02v, 6-4 4.58v, 6-3 5.02v and 4,63v.

If you have 0V between Step+ and Step- or Dir+ and Dir-, this means that
one or both of the Step/Dir output driver chips have been damaged.

How much static voltage should i have been able to get ?
Are those the two chips in front of the TB2 connectors?

Without load you should always get +5V or -5V from DIR+ to DIR- and STEP+ to STEP-
(5V or -5V depending on the output state, STEP+ and DIR+ should always be the logical inverse of STEP- and DIR-)

The driver chips are a 74ACT540 (U12) and a 74ACT541 (U19)

I have to admit that i over powered the P3 connector by putting the terminal of the positive on the 12 volts instead of the 5 volts. Dumb mistake.
I was hoping for the best since nothing was connected to it and no other components show any traces of damage. So these are the octal buffers that create the step/dir signals or act more like the ones in a computer clocking the bits?

Thanks you have been very helpfull. I realy appreciate the time you spent helping me. You seem to know a lot about these cards.What do you do for a living?

ggsxx wrote:

Thanks you have been very helpfull. I realy appreciate the time you spent helping me. You seem to know a lot about these cards.What do you do for a living?

PCW = Peter owns Mesa so you can't get better that that. The best and quickest help you can fine.

"So these are the octal buffers that create the step/dir signals or act more like the ones in a computer clocking the bits? "

They are just level shifters from the 3.3V outputs of the FPGA to 24 mA 5V outputs to interface with the step/dir drives.

Can i get an estimate to get it fixed?