diff --git a/board/czechlight/common/overlay/usr/lib/systemd/system/cla-i2c-adt7463.service b/board/czechlight/common/overlay/usr/lib/systemd/system/cla-i2c-adt7463.service
index aa07348..50f8868 100644
--- a/board/czechlight/common/overlay/usr/lib/systemd/system/cla-i2c-adt7463.service
+++ b/board/czechlight/common/overlay/usr/lib/systemd/system/cla-i2c-adt7463.service
@@ -7,8 +7,27 @@
 
 [Service]
 Type=oneshot
-# Configuration for two-fire fans
+
+# Configuration for two-wire fans (0b1111)
 ExecStart=/sbin/i2cset -y 1 0x2e 0x73 0x0f b
+
+# Set up the AC voltage threshold to:
+# +/- 20mV: 0x00 (default)
+# +/- 40mV: 0x04
+# +/- 80mV: 0x08
+# +/- 130mV: 0x0c
+ExecStart=/sbin/i2cset -y 1 0x2e 0x7d 0x0c b
+
+# Pulses per revolution:
+# 1: 0x00
+# 2: 0x55 (default)
+# 3: 0xaa
+# 4: 0xff
+#ExecStart=/sbin/i2cset -y 1 0x2e 0x7b 0x55 b
+
+# Faster (250ms) period for TACH monitoring
+ExecStart=/sbin/i2cset -y 1 0x2e 0x78 0x08 b
+
 # ADT7463: Register as an I2C device
 ExecStart=/bin/sh -c 'echo adt7463 0x2e > /sys/bus/i2c/devices/i2c-1/new_device'