Comark RF500A/AP Service Manual
Tier 3: RF500A Component Level Repair
In Circuit Testing
The testing detailed here should be performed on a PCB with the PC module removed but the battery in placed and
charged, any test requiring a deviation from this criteria will specify in the instructions.
The test header is a 10 pin connector located to the right of the RF module:
Most of the useful test points are accessible via the test header J311:
Name
Description
Pwr
Common power rail
3VC
3.3V permanent power rail to U421
RST IN
Reset line to PC module
TEST MODE
Not used
RXD1
Receive coms line to U421
5V
Switched 5V rail
3VM
3.3V switched rail
0V
Ground
TXD1
Transmit coms line to U421
0V
Ground
17 November 2011
Page 40 of 65
J311 Test Header