diff --git a/PDP10/kx10_mt.c b/PDP10/kx10_mt.c
index fe625f6..020e974 100644
--- a/PDP10/kx10_mt.c
+++ b/PDP10/kx10_mt.c
@@ -615,7 +615,7 @@ t_stat mt_srv(UNIT * uptr)
             if (uptr->flags & MTUF_7TRK) {
                 cc = 6 * (5 - uptr->CPOS);
                 ch = mt_buffer[uptr->BPOS];
-                if ((((uptr->CNTRL & ODD_PARITY) ? 0x40 : 0) ^
+                if ((((uptr->CNTRL & ODD_PARITY) ? 0x40 : 0) ^ (ch & 0x40) ^
                       parity_table[ch & 0x3f]) == 0) {
                       mt_status |= PARITY_ERR;
                 }
@@ -694,7 +694,7 @@ t_stat mt_srv(UNIT * uptr)
          if ((uptr->CNTRL & MT_BRFUL) != 0) {
             if (uptr->flags & MTUF_7TRK) {
                 ch = mt_buffer[uptr->BPOS];
-                if ((((uptr->CNTRL & ODD_PARITY) ? 0x40 : 0) ^
+                if ((((uptr->CNTRL & ODD_PARITY) ? 0x40 : 0) ^ (ch & 0x40) ^
                       parity_table[ch & 0x3f]) == 0) {
                       mt_status |= PARITY_ERR;
                 }