I just repaired a Beomaster 5500 with various problems, and it is now playing nicely.

However, I had to temporarily disconnect the backup battery to clear some unknown timers. Then it of course asks me to set the clock, which I did, but each time I turn it on, it says "SET CLOCK" on the MCP. Is there some trick related to this? The radio presets I programmed stay put just fine even if I unplug the BM for a while, so the backup battery & memory should be OK.

Another thing I don't understand is that the '+' sign for "more than 14" shows on the MCP when the radio status is displayed, even though I have only a couple of presets programmed. Is there still some confusion in the NVRAM and I should keep  the battery disconnected for a longer time, or is there any other way to "format" it?

It also does not talk back to my BL7000, but I guess this is a software version issue and by design?

Never mind the clock part - I just realized that unlike BM6500, the PCD8571 RAM chip used in 5500 doesn't have an RTC function at all! So there's nothing keeping the time while the 5500 is unplugged, it does that in software.

Other questions still hold, though

Got even the '+' sorted - it really had a programmed preset number 20 even though the memory was cleared otherwise.