Polar 115 EM code 87 when try to cut

Good morning to the forum members. This is a Polar 115 EM guillotine. The code 87 is displayed on the screen when the cut is pressed. The other functions have not been affected. The protocol has already been reviewed according to the service manual but the origin of the problem has not been found. Apart from what is recommended in the service manual, does anyone have information on what other origin this code 87 could have?
As additional information, the paper pressing crossbar is acting quite slowly, but we believe that it is an unrelated fault. Thank you in advance for your opinions.

Best regards

 

Check the cut buttons and the wiring going to them. 87 indicates both normally open and normally closed cut buttons are activated at the same time.

 

Hello ESPofKC,

This point was checked. The wires are ok. The NC and NO contacts inside the cut buttons are ok. But the code error remains when try to cut. If you have some more points to check let me know. Than you.

 

On the SK board, check LED v73 and V74 should be lit. When A cut button is pressed, V73 should go out and V76 lights up OR V74 goes out and V75 lights up. Check these red LEDs.

 

Hello ESPofKC,
Thank you for your reply.
This Polar EM model is older that you are talking about. In this model do not exist the SK card, Instaed of that it have the HK card when you can monitor the reactions of the two cut buttons and its internal NC and NO contacts. In this case the leds related are called V6, V7, V8 and V9. Is was cheked and the four signals are received as expected.
But the failure remains.
I remain attentive to any other hypothesis.

Thank you for your reply

 

Does your machine have cam switches or sensors with an this board

 

Hello Andy Martin and other members interested,
Thank you for your support
The last week it was possible to make a test changing the IAR card. The problem was fixed. This card is damaged. Now the machine is working.