MCP4725 i2c not detected on Beaglebone Black?

[dutch999]

Hi, I am trying to interface the MCP4725 DAC to Beaglebone Black (rev c w/ latest standard debian image) over i2c to output analog voltages. Running the command "i2cdetect -y -r *" in bash fails to identify any i2c connections. Any help would be greatly appreciated...

[adafruit_support_rick]

Please post clear, detailed pictures of both sides of the module, showing your soldering andwiring

[dutch999]

Ok, I will work on getting some images up. In the mean time... I have been able to get the BBB to identify i2c on channel 0x62 (i've read it is the default) using bash command "i2cdetect -y -r 1" by re flashing the BBB with the latest debian image. However for some unknown reason, eventually the same bash command fails to detect anything on i2c1 (and the scan of i2c1 is extremely slow). Hopefully this may shed some light on the issue...

[adafruit_support_rick]

Check your solders. The solder should flow completely over the pad and up the pin. You must heat both the pad and pin simultaneously. A good joint will look like this:

[dutch999]

I think you're right. When I move the DAC board a little bit in the bread board, I can get i2c to be detected and then not detected. Is i2c particularly sensitive to good solder joints? I've been soldering for a while and I don't think I've ever had this problem with header joints. Thanks for your help.

[adafruit_support_rick]

I don't know that I2C is particularly sensitive to solder joints, but it is 400kHz, so good connections are essential.
Could be a bad breadboard socket. Try a different location. Make sure you have a good ground connection.
We've seen I2C devices that show up in i2cdetect but don't work, and it always seems to come down to a bad ground.