MCP3208 input voltages erratic

[Sprocket]

I am experiencing problems with all the MCP3208 inputs. all apear to be constantly varying. It is causing the Digital input switch (ch7) to flicker on and off when the input is not grounded. When you ground the digital input switch (ch7) all the inputs are pulled to zero volts with only the odd flicker of life randomly across the input channels as can be seen in Megatune. This is also true for the EGT channels.

I have been unable to get the EGT channels working since I had the issues back in December. I did replace the EGT chips, but they did not make any difference. I have since removed the wiring from the board for the EGT thermocouples, but left the chips onboard.

The plan for tomorrow is to remove both EGT chips and remove the solder blobs, to see if this will make any differnce.

Other than this, does anyone know what actualy might be causing this?

[Sprocket]

i HAVE ORDERED AN mcp3208 JUST INCASE :-\

oops caps lock :D

[Sprocket]

I think there is an issue with the switch wiring, which is pulling the 5v down. However, I still think the MCP3208 is faulty. ALL 8 input channels are pulled high 5v and when channel 6 is grounded, all channels are pulled low 0v, yet any other channel connected to ground, does nothing. A switch connected to channel 6 irrespective of which channel is configured activates the feature being configured for the switch, IE ALS, Launch and so on.


Can any one please tell me if I am going in the right direction ???

[gunni]

Replace it.
Sounds like the chip is bad.

[Sprocket]

Finaly got round to replacing this chip, and I am glad to say that ADC 5,6 and 7 now work as they should. Not checked the EGT yet.