diff --git a/neo/rawio/tdtrawio.py b/neo/rawio/tdtrawio.py
index a0e3cb673..cd6a0e49b 100644
--- a/neo/rawio/tdtrawio.py
+++ b/neo/rawio/tdtrawio.py
@@ -283,11 +283,12 @@ def _parse_header(self):
                             raise ValueError("Dtype is changing!!")
 
                     # data buffer test if SEV file exists otherwise TEV
-                    # path = self.dirname / segment_name
                     if self.tdt_block_mode == "multi":
                         # for multi block datasets the names of sev files are fixed
-                        sev_stem = f"{tankname}_{segment_name}_{stream_name}_ch{chan_id}"
-                        sev_filename = (path / sev_stem).with_suffix(".sev")
+                        block_path = self.dirname / segment_name
+                        sev_regex = f"{tankname}_{segment_name}_{stream_name}_[cC]h{chan_id}.sev"
+                        sev_filename = list(block_path.glob(sev_regex))
+                        sev_filename = sev_filename[0] if len(sev_filename) == 1 else None
                     else:
                         # for single block datasets the exact name of sev files is not known
                         sev_regex = f"*_[cC]h{chan_id}.sev"