diff --git a/dashboard.py b/dashboard.py
index 1f69bcf..0294f45 100644
--- a/dashboard.py
+++ b/dashboard.py
@@ -164,7 +164,7 @@ class TimeSeries(Widget):
                             / math.log(max_value / min_value)
                        ) * 200
             elif self.yscale == "linear":
-                return (1 - v/max_value) * 200,
+                return (1 - v/max_value) * 200
             else:
                 raise ValueError(f"Unknown yscale {self.yscale}")
 
@@ -413,6 +413,7 @@ class TimeSeries(Widget):
             html += f"<line x1={tm['x']} y1=0 x2={tm['x']} y2=200 stroke='#CCC' />"
             html += f"<text transform='translate({tm['x']}, 210) rotate(30)' fill='#888'>{tm['t_h']}</text>"
         for tm in self.y_tickmarks:
+            log.debug("tm = %s", tm)
             html += f"<line x1=0 y1={tm['y']} x2=1000 y2={tm['y']} stroke='#CCC' />"
             html += f"<text x=1005 y={tm['y']} fill='#888'>{tm['v_h']}</text>"
         for v in v_data: