With nothing on the GPIO pins (including no fan shim) the I2C works normal. sudo i2cdetect -y 1 completes all addresses near instantly. Mount the Fan Shim, mechanical only - no software: I2C fails. sudo i2cdetect -y 1 takes over a second per address How to prevent the Fan Shim from interfering…

Working Ok here for me, Pi 4B 4 gig running Buster. My Fan Shim is soldered to a booster header. I don’t know if it matters but I didn’t install the fan shim software. EDIT: I guess I should also mention that I currently don’t have any i2c devices connected.

The BCM 3, pin 5 wake connection is to the button. My understanding is a ground is placed on pin 5 when, and only while, the button is pressed. If you don’t touch the button on the fan shim nothing should be connected to pin 5 other than a trace on the circuit board going to an open circuit. If you…

Solved it. The case I use is a tight fit. Mounting the Fan Shim presses the button against the side of the case. Physically removing the button from the Shim solved my issue.

[image] PiTinker: I considered making a dumb shim I ended up cutting new pieces out of acrylic and getting 5V and ground from GPS and RTC hats that I have attached to all my RPis. Now my problem is that the fans aren’t actually lasting that long. I’ve replaced a couple with a different type…

Ah nice to hear you figured out what was going on.

These may be of use to you, to mount fans too. [image] Pibow Modification Layers (not suitable for Raspberry Pi 4) – Pimoroni Store Need to adapt your Pibow to fit your project? These handy extension layers will sort you out! The Difussers are precut and have …

Fan Shim blocks I2C

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PiTinker November 10, 2019, 6:44pm 2

I considered making a dumb shim, but pins 3 & 5 are not so easily circumvented

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Fan Shim blocks I2C

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