Heidelberg Press KLM4 Isolation is an isolation transformer and power‑distribution board that supplies conditioned AC to the press’s drive, control, and safety circuits. Common failures on this model include insulation breakdown between primary and secondary windings, tripped or blown fuses in the isolation circuit, and degradation of internal capacitors or relays due to vibration or over‑voltage spikes. For troubleshooting, first verify that the main power supply is delivering the correct voltage and that all input fuses are intact; next inspect the isolation transformer for visible arcing, scorch marks, or loose connections; finally review any error codes in the press control system related to “isolation fault” or “transformer overload.”[oss-gpt-20b]