If your FT-817 has stopped powering up from the internal battery but works from external power, then maybe the internal battery fuse has blown.
There is a small PCB mounted fuse to protect the battery and radio. This fuse can blow, if it does your radio will not work from battery power.
This page will describe how to test the fuse and describe how to make a repair.
The symptoms for a blown internal fuse are as follows (there are other possible causes so do check these first):
Note: Make sure the battery is fitted and connected
Note: Make sure the battery is not discharged
The internal battery power circuit has a resettable fuse in series with the battery. Unfortunately, resettable fuses don't always reset.
If your battery is shorted out, or the battery is connected with reverse polarity when trying to connect the plug, this fuse will go pop.
First, you'll need to order the following components:
These fuses are available from most online auction sites. A pack of ten should cost around $1.
Please don't try to replace this fuse if you are not confident with the removal and refitting of SMT components. Some care is needed when replacing these devices. Consider asking somebody who is skilled with these things if needed.
That's it! Your FT-817 should be fixed.
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