diff -r -U2 ComponentTester-1.47m.orig/probes.c ComponentTester-1.47m.fix-testpin-free-assignments/probes.c
--- ComponentTester-1.47m.orig/probes.c	2022-02-18 17:57:40.000000000 +0100
+++ ComponentTester-1.47m.fix-testpin-free-assignments/probes.c	2022-12-09 19:55:39.079013128 +0100
@@ -364,5 +364,5 @@
       continue;
 
-    U_c = ReadU(ID);                    /* get voltage of probe */
+    U_c = ReadU(DATA_read_byte(&Channel_table[ID]));  /* get voltage of probe */
 
     if (U_c < U_old[ID])                /* voltage decreased */
@@ -413,5 +413,5 @@
       Flags = DATA_read_byte(&Rh_table[ID]) | DATA_read_byte(&Rl_table[ID]);
       R_DDR &= ~Flags;                  /* disable load resistors */
-      Check.U = ReadU(ID);              /* get and save voltage */
+      Check.U = ReadU(DATA_read_byte(&Channel_table[ID]));  /* get and save voltage */
 
       Counter = 0;                      /* end loop */
@@ -942,5 +942,5 @@
       wait5ms();
       R_DDR = Probes.Rl_2 | Probes.Rl_3;  /* pull down base via Rl */
-      U_1 = ReadU_5ms(Probe2);            /* get voltage at collector */ 
+      U_1 = ReadU_5ms(Probes.Ch_2);       /* get voltage at collector */ 
  
       /*
@@ -978,5 +978,5 @@
       R_DDR = Probes.Rl_1 | Probes.Rl_3;     /* select Rl for probe-1 & Rl for probe-3 */
       R_PORT = Probes.Rl_1 | Probes.Rl_3;    /* pull up collector & base via Rl */
-      U_1 = ReadU_5ms(Probe1);               /* get voltage at collector */
+      U_1 = ReadU_5ms(Probes.Ch_1)           /* get voltage at collector */
 
       /*