[Mustafa01980]

Hello everyone.
When I checked the Cycle start and feed hold buttons in the relevant register in the diagnostic menu on our Mazatrol Quicturn 8 model machine, I found that they were not active. During my circuit monitoring, I found that the button pins first entered the BLB terminal in the CRT section and then entered the keypad card. From here on out, it's not in my circuit diagram. With this malfunction, the handwheel does not work and the LEDs behind the encoder light up sequentially. In the measurements I made with the 12V ground coming to the encoder at the button ends, I see 12V constantly, whether I press the button or not. When I measure the pin connected to the Cycle start signal (STS) card at idle, there is 12v. I don't have time to review Keypad today. Is this card just for interface? Which card at the back could be causing the malfunction? Can you help me?

[Mustafa01980]

In my checks, I cannot see ground at the CM3 common button end. 12V pulldown on the button ends is working. X and Z axis encoder selection is also connected to the CM3 terminal and it does not work either. The circuit diagram does not show where the CM3 lead comes from. I found it up to the TB3-L terminal, but I haven't found anything beyond it yet.

[Mustafa01980]

I detected and replaced the faulty integrated circuit on the FX-709C board and the problem was solved.