A few days ago my power supply gave over 20V to my poor Yaesu 7800. Radio died. I reconnected the transceiver to a spare power supply but radio remained dead. I checked the fuse and I found the fuse has been blown. Unfortunately changing the fuse did not help 🙁 The fuse got blown again 🙁
After a small research on the internet I found that in all Yaesu (and not only) radios there is a diode P6KA 18 which protects the radio from too high voltage. When it happens the diode usually gets shorted. In my particular Yaesu 7800 the diode has a number D1033 and is located as shown on the picture below:
Repair was very simple. I just cut off the diode from the PCB, the picture shows an empty space from the diode 🙂
Now the radio is not protected, but I do not care 🙂
RIP diode:
Thanks for this article. Had the exact same issue, although I’ve got a replacement diode coming I’m going to try to install.