Need Help!- Help diagnose a problem in my board (or PC)

[eran k]

Hi All.
I posted this in "Electronics" forum but got no answers so i hope to get some advice here.

I have one of the ebay 4 axis TA8435H boards.
It was working ok with my machine and PC,then few days ago mach 3 started freezing the PC every time i tried to load it, i began to mess around with diffrent settings like paralel port mode (ECP,EPP,ECP+EPP...), re-installed mach3 and so on.
i got mach3 to run again but now i get no response from my board, tried many many diffrent pin settings,tried to configure just one motor to work but NADA, the board is on - i see some red LED's, but the ones that should work when one of the axis is moving never turn on.
Also the motors are not in step hold if thats how it's called- i can move them by hand when the board is on,this was not possiblle before.
how can i tell if i blew my board,or my paralel port or somthing else,i'm quit desperate at the moment and dont know what else to do

I did some more tests and found out this:
when an axis is moving in the software the correspondinf motor cant ve moved by hand and i read voltage in the board motor terminal,but the motor does not turn (smae on for all 4 motors)
how can i diagnose if it's a problem with board or the paralel port?
thanks
Eran

[rlwoodjr]

If you have a volt meter you can test the parallel port pins.

[lunchtrayrider]

try making your enable pin active low.

[eran k]

What do i need to check at the Parallel Port, and when?
Eran

[eran k]

I checked with a voltmeter and found somthing strange:
all the output pins are constantly ON putting out 4.34 volt all the time no mattter which axis i jog,they voltage is there from the minute the computer is on.

[brtech]

Is your parallel port in EPP mode? It MUST be in EPP to work.

Do you have an older printer you could use to test out your parallel port?

Testing with a multimeter isn't going to tell you much.

[rlwoodjr]

I have old hp compaq laptops. I used a volt meter to see 3.3 vdc to ground for the step and direction pins. I am not sure what mode my port is in, but I use Turbocnc to generate a slow step that I can see with the voltmeter. Direction is easy because it is either 3.3 or zero.

Originally Posted by brtech Is your parallel port in EPP mode? It MUST be in EPP to work. Do you have an older printer you could use to test out your parallel port? Testing with a multimeter isn't going to tell you much.

[brtech]

Is your parallel port in EPP mode? It MUST be in EPP to work.

Do you have an older printer you could use to test out your parallel port?

Testing with a multimeter isn't going to tell you much.

[pfred2]

"Testing with a multimeter isn't going to tell you much. "

I can see a high or low signal from a parallel port with a meter, if the line is not changing states too quickly. If it is a fast square wave then an oscilloscope is easier to use. But I would just use a program that set the port to known states to avoid that situation. It isn't like parallel ports are completely beyond human control after all!