Próba Zwarciowa

Spider12 napisał(a):Czemu trzeba zawsze odłączać przetwornice przed zrobieniem próby zwarciowej , tak jak na obrazku ?

Because the electrical current during a short circuit test will also flow into the "Switch node pin" (in your case "+5V_ALW_PHASE") of switching controller chip.

Spider12 napisał(a):co się może stać gdy tego nie zrobię ?

The switching controller chip will heat up in this case although it is fully functional.
In some cases this may damage the controller chip.

In the case of performing a short circuit tests on "LDO output" power rails it is especially important to disconnect the LDO regulator from the power rail, because the electrical current during a short circuit test will also flow into the output pin of LDO regulator which is much more sensitive to such damage than "Switch node pin".