diff --git a/tube.ino b/tube.ino
index d39f81c..69c9228 100644
--- a/tube.ino
+++ b/tube.ino
@@ -6,7 +6,11 @@ char tubeText[5] = "";
 void initTube() {
   // Wire initialized by BME280 sensor
   tube.setTubeType(TYPE_4, TYPE_4_DEFAULT_I2C_ADDR);
-  tube.setBrightness(15);
+  // Brightness drives LED current. The freeze correlates with '8' on the last
+  // multiplexed digit (most segments lit -> peak current) at full brightness 15,
+  // which points at a supply/I2C-bus glitch. Lowered to probe that hypothesis;
+  // raise back toward 15 if the display is too dim and freezes don't return.
+  tube.setBrightness(4);
   tube.setBlinkRate(BLINK_OFF);
 }