Repairing the dead mic input of my TS-870S. Click the image for larger version.
1. The TX-RX Board is located at the bottom, so upside down it is
2. The metal cover on the right has to be removed
3. Disconnecting all the cables from the TX-RX board
4. Board removed. Note the updated firmware in 3 EEPROM’s
5. The bad AD822 op-amp chip is in the upper right quarter
6. Soldering the new AD822 in place under a stereo microscope
7. Now let’s fill the void and put the TX-RX unit back in place
8. Testing the unit.. excitement
It feels great if you diagnosed the problem correctly and being able to fix it yourself. Total repair cost: 5 euro. Time needed: about an hour. Thanks to Evert PA3FXY for bringing the 150W dummyload and letting me use his SMD soldering station and microscope.