diff --git a/library/model_util.py b/library/model_util.py
index 26f72235..70a8c752 100644
--- a/library/model_util.py
+++ b/library/model_util.py
@@ -540,6 +540,11 @@ def convert_ldm_clip_checkpoint_v1(checkpoint):
     for key in keys:
         if key.startswith("cond_stage_model.transformer"):
             text_model_dict[key[len("cond_stage_model.transformer.") :]] = checkpoint[key]
+    
+    # support checkpoint without position_ids (invalid checkpoint)
+    if "text_model.embeddings.position_ids" not in text_model_dict:
+        text_model_dict["text_model.embeddings.position_ids"] = torch.arange(77).unsqueeze(0) # 77 is the max length of the text
+
     return text_model_dict