kiev
Posts: 1704
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

MCU troubleshooting and repair

Wed Nov 24, 2021 8:31 am

It seems that many reports of problems with the MCU involve the P1A15 trouble code, and there are several threads and numerous posts about this DTC in the forum.

This thread will attempt to collect the technical information of the MCU to assist in making repairs.

Description of MCU functions
Pictures
Schematics
Parts List
etc,

Just for now i am putting this note about the hybrid board circuit here and will move it later.

There are test points along the side of the board in a single line of large diameter vias or solder pads. Starting from the corner of the board they are unlabelled and grouped in 6, 6, 8, and 6 vias. i'm going to call those groups A, B, C and D, and pin 1 of each group is the square pad at the end of each group that is connected to the ground plane.

U29 is an op amp used as a unity-gain buffer for the hybrid board output pin 3, which enters U29 on pin 5 and exits on pin 7, then goes thru 1K R245 to a diode D207 and on to a tiny via to pin 34 of the micro U1. The diode is for over voltage protection of the micro in case the signal voltage is too high. The input and output of U29 should be the same voltage unless there is a defect, so you can compare hybrid pin 3 with the test point voltage at "B6" to check for a problem. i think this is the signal read by the micro and reported in the live data on the CAN buss.

U16 is a comparator chip used with a hysteresis circuit to detect a set voltage level and rapidly change its output state to signal the microcontroller that the threshold has been reached. The set point is determined by a resistor divider of R243 and R241 using the voltage that is found on test point "A5". i will need a measurement of the voltage on A5 in order to calculate the threshold voltage.

The U16 output state switching can be seen on test point "B4". There is a pullup resistor R244 and low pass filter R247 and C244 with a tiny via that goes into the micro U1 pin42. This is just a switching signal for detection of a threshold probably used like an indicator for an On/Off switch.
kiev = kenny's innovative electric vehicle

kiev
Posts: 1704
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

MCU function description and problems

Wed Nov 24, 2021 8:31 am

placeholder
kiev = kenny's innovative electric vehicle

kiev
Posts: 1704
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

MCU Schematics and Parts

Wed Nov 24, 2021 8:32 am

PH
Last edited by kiev on Wed Nov 24, 2021 8:33 am, edited 1 time in total.
kiev = kenny's innovative electric vehicle

kiev
Posts: 1704
Joined: Sun May 03, 2015 7:15 am
Location: The Heart o' Dixie
Contact: Website

MCU Pictures

Wed Nov 24, 2021 8:33 am

PH
kiev = kenny's innovative electric vehicle

Return to “General Technical Discussions”