Hello everyone

Last night my TZ decided to stop sensing the powerball in the trough. And it gave me a switch 26 error.

I have been searching the internet, and reading up on the issue, but there is something i think i need clarified.

In my case the red LED on the driver board is constantly on. I then read in another thread on pinside that if i removed the connector to the sensor (coil) board and the LED was still on, this would mean that my driver board was fried. And when i disconnected the sensor board from the driver board, the LED stayed on. So i guess my driver board is shot...? Or is it...?

I wanted to check if the same was true for my working ToM. And this is where i got confused... On my ToM the LED is off until a ball passes the sensor. But if i disconnect the sensor board, the LED actually turns on. So it seems that if the "loop is open" the LED also turns on? And if this is true for TZ as well, the fault could just as easily be with the cable or coil on the sensor board?

So can anyone confirm: If i disconnect the sensor board from my TZ's driver board - should the LED be on or off?

Hope all of the above makes sense despite my poor english

...and does anyone happen to know the resistance of the sensor coil? That would also be really helpful info.

Thank you for your input.

I know that it is supposed to be off by default, and then switch to on when a steel ball is registered.

What i would like to know is, if the LED should be on or off when i completely disconnect the sensor board?

Ok. In that case the board in ToM must be different, because on that board the led lights up when the sensor board is disconnected.

OK, i just had another TZ owner confirm, and when disconnecting his sensor board from the driver board, the LED indeed turns ON. So that means that it has the exact same behavior as i expected, and that my RS and ToM also have.

So either there are differences from TZ to TZ that causes this, or the posts saying the LED should be OFF when the sensor is disconnected, are based on wrong information.

So i guess i will start by checking all connections between the driver and sensor board.

True, that could be it.

But I understand why it would be easy to assume that if the sensor (2 pin plug) is disconnected, of course the led would be OFF, since it would not be able to sense the ball (or any other metal). But the fact is that the LED actually turns on when the loop is open.

Thats great info, and in that case it all makes sense.

Thank you for elaborating.

And no problem about the wrong advise. It can be hard sometimes to explain an issue in a language other than your native one. But that is what is so great about a community like this - the amount of knowledge and people willing to help out there is just awesome!!

Guess I'll have to pull out the sensor tomorrow and check all of the connections. I measured the resistance of the coil, through the 2 pin connector to the sensor board. It measured 1.1 ohms. That seems a little low?

I forgot to update this post.

But it was indeed my driver board that was shot. A new TDA chip and it was working again.

So for others looking for info about the LED on/off as discussed here, i can confirm that when working correctly, and you disconnect the 2 wires to the sensor board, the LED should turn ON!