Power Supply To Motherboard - Bosch ETT 008.31 Repair Instructions

8.17

Power supply to motherboard

Also refer to circuit diagram in Sections 12.1 and 12.2.
This diagram illustrates the voltages at the transformer and filter capacitor C 1 and their distribution in the exhaust-gas analyzer.
Diagram, power supply to motherboard (simplified representation)
Here, check that the voltages on the motherboard are in conformity with the table below. If not, also check the source voltages at the
transformer in accordance with Sections 12.1 and 12.2.
Test point Designation
X 16 MA
X 17 P 12 VA
X 18 N 12 VA
X 13 P 5 V (U
Ref
X 10 MD
X 14 N 5 VD
X 15 P 5 VD
X 50 MS
X 51 P 12 VS
X 52 N 12 VS
X 53 P 18 VS
50
Voltage
Reference point ANA.
+ 12.0 V + 1.0 V
- 12.0 V + 1.0 V
) + 5.0 V + 10 mV
Reference point DIG.
- 5.0 V + 0.5 V
+ 5.2 V + 0.1 V
Reference point interface
+ 12.0 V + 1.0V
- 12.0 V + 1.0V
+ 18.0 V + 3.0V
Adjustable at
- - -
- - -
- - -
R 12
- - -
- - -
R 3
- - -
- - -
- - -
- - -