F06 pos. Pressure Test detuning results in a change in the measuring range of less than 85 mmHg (60 sec). – The D-A converter (IC11) on P.C.B. LP 632 is defective. – Acknowledgement (P_DIAL, X633L/B6) → X632/A29, change in voltage insufficient. – Detuning defective (P_DETADJ, X632/C20) → X633R/C22. – V26 is leaky.