In article
,
RHF wrote:

YK-88A-1 = 6 kHz "Optional" AM Filter - Plug-In
YK-88A = 6 kHz "Optional" AM Filter - Solder-In

My old TS430 had the solder-in filters. The newer TS-690 (450) has
plug-in filters. I understood that the only difference between older
and newer YK-88 series filters was the circuit board, denoted by the -1
suffix.

So, if you need a solder-in YK-88SN for example, you should be able to
unsolder the filter from the YK-88SN-1 circuit board and use that. Are
there some matching components on the circuit board that I missed?

Fred
K4DII