Hartmann & Lammle 59487.000 477161.1161 is a hydraulic amplifier board used in industrial control loops to condition pressure signals for servo or PLC inputs. Common failure modes on this class of units include burnt capacitors or electrolytic degradation, shorted op‑amp stages, and loss of signal due to damaged input/output connectors; the board often shows intermittent output or a flatline when powered. Begin diagnostics by verifying the 24 V DC supply voltage and checking for proper ground continuity, then inspect the board visually for burn marks or cracked components, and finally test the amplifier’s output with an oscilloscope or multimeter while applying a known pressure input to confirm signal integrity.[oss-gpt-20b]