Upon opening the transceivers, I quickly saw what looked like water damage on the IF crystal filters:

You can see some white deposit on those filters. My guess is that after re-flow/wave soldering these boards, Yaesu probably washes these PCB’s. However, the plastic used in these filter either is brittle, porous, or the bottom isn’t hermetically sealed.

Removing these filters is a pain in the ass. And I’m not overreacting here. The ground plane in this PCB is quite good and you can really struggle to get the solder out. (lead-free as well!). Here’s the PCB with the filters removed:

Looking at the flux in other places on this board, I suppose this transceivers has had work done before…

I opened up one of these filters to get an idea of the damage done. A sharp blade does the trick:

You can clearly see the copper oxide. No wonder this thing was deaf!

Anyway, it’s worth opening up your transceiver if you have an FT-897 to check and see if there’s any of that white “powder” on those filters. Big red flag if you see it.
Here’s a picture with already one new filter in place. Make sure to put the right filter in the right place…

---