Tag Archives: tracker3

DR-135 TNC 5V regulator modification

I recently acquired an Alinco DR-135 radio with an integrated EJ-41U TNC unit.
I decided to replace the TNC with an Argent Data Tracker3 T3-135 module. After installing the module, however, the TNC board would not power up.
I measured the 5V line feeding the TNC module at around 3.5V. When I replaced the module with the original EJ-41U, I measured around 3.8V (although that unit seemed to work OK, even on such a low voltage).
Update: If anyone is doing this mod, don’t pull power from the 7808 like I did. See below..
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