Hotbed motor homing, but doesnt work when printing

Hello everyone.
Has anyone encountered problem like this?? Its homig like every other motors, stepstick is working too, but not working when it come to print.
2 weeks ago it was doing great.
I got old reprap based on at90usb1287 sunbeam B board, normal nema17 motors. I dont know what firmaware is inside,
im scared to burn another one cause what if there are different settings, like different than ramps 1.4?
I checked pin with scope and it showing signal on STEPS pin. But only when it homing that Y axis.
Like Firmware is screwing something.

Homing speed is usually slower than print speed. Maybe the z-motor doesn't get enough current from the stepstick? The Vref potmeter might have a bad contact. ( Caramba, WD40 at hand? )
Another reason could be binding. Check the mechanic and add a drop of oil to any moving part.

Thansk for responding. Well no mechanic is good. And i switched stepsticks. Works well for any other motor. Just Y doesnt move during print. But it does homing.
There is NO SIGNAL from microcontroler during only printing or mowing in pronterface. But there is signal when homing.
Is there somwhere pinology for old Sunbeam borads? Like which pins are doing STEPS and DIRECTION? Maybe there is cutet somwhere.

... it will show similar behaviour with inverted polarity of the home-switch signal - then it will only move in one direction and no pulses while printing, as the axis is not homed/positioned properly ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

... it will show similar behaviour with inverted polarity of the home-switch signal - then it will only move in one direction and no pulses while printing, as the axis is not homed/positioned properly.

Maybe wire to the switch broken or no connection?

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

No wiring is ok. I tested. Its like microcontroler choosing to not to work for Y move only when printing.
Can someone provide hex for sunbeam board? With at90usb1287? Ill try to reflash it.

Now i ruined FW. I need hex for this old board Sunbeam B and i have no idea if its even gonna work propperly.