Tait TB8100, Service Manual

Page: 161 / 306

TB8100 Service Manual Power Amplifier Fault Finding 161
© Tait Electronics Limited September 2006
4. Measure the resistance of the termination resistor to ground. It
should be 50
Ω
. If it is, the splitter board is not faulty. Proceed to
“60W Board” on page 162 . If it is not, proceed as follows:
■
if the resistor is SMD, replace the splitter board
■
if the resistor is mounted on the heatsink, replace the resistor and
repeat the test (refer to
“Replacing the Splitter/Combiner
Boards” on page 190 ).
Task 2 —
Check the Combiner
Board
1. Check the DC continuity from port 1 to the output, and from port 2
to the termination resistor. If there is continuity, go to
Step 3 . If
there is not, go to Step 2 .
2. Check for faulty solder joints between the combiner and the PCB. If
the solder joints are not faulty, replace the combiner board. If there
is a faulty joint, repair as necessary and repeat
Step 1 . If there is still
no continuity, replace the combiner board.
3. Check that there is no DC short to ground on each of the four ports.
If there is a short, replace the combiner board. If there is not, go to
Step 4 .
4. Measure the resistance of the termination resistor to ground. It
should be 50
Ω
. If it is, the combiner board is not faulty. Proceed to
“60W Board” on page 162 . If it is not, replace the termination
resistor and repeat the test (refer to “Replacing the Splitter/
Combiner Boards” on page 190 ).