These were fitted to 740s, and maybe 760s. They look like this.
I'd like to replace the TD-6146 in the 780 with something that looks OE, and is capable of tuning into Australian FM stations properly. The 6146 is the 780 version of the 6141 (different front panel).
The 780's existing unit is US spec, and the US has different radio channel spacing on AM and FM.
A fully working example would be nice. An non-working cassette unit is okay.