Welcome to the Panbo Marine Technology Forums.
I realize PANBO is WAY beyond mundane issues and products like this, and maybe it might be beating a dead horse, i.e. "why bother, throw it out and buy something else"...
...but did anyone ever find out what the "mystery" component was that's no longer manufactured, so when the RX section of the Uniden UM525 goes dead, it can't be repaired ?
Yes, I've moved on to a Lowrance Link-8, but I've always been an electronics tinkerer, and hate to throw out a great VHF that still transmits, and with all the bells and whistles short of AIS.
The problem is sort of "well-known" but not really documented. As a HAM, I'm surprised no radio heads have posted anything I can find on the issue.
As Panboians are a more technical lot, I thought it worth tossing this message in a bottle and see what might turn up. 😎
I remember the Wham wireless mics fondly -- and especially the ahead-of-its-time color ES VHF, one of which is still working fine in my shop -- but I'm afraid that your UM545 is now in the "can't even give it away" category.
https://panbo.com/uniden-es-vhf-series-late-but-great/
What I was hoping by posting on Panbo is someone here would have a deeper technical knowledge beyond "consumer level," of what specific electronic component it is that is no longer manufactured, preventing the UM525 from being repaired ? That was the last I read. Like some specific RF diode or IC in the Rx section ?