Anybody have any idea where to get a replacement tunnel diode for the 284. The manual tells me it is D180, part 152-0329-00 Diode Tunnel 21mA 20%. No other identifers. The thing looks a bit like a MAR 6 MMIC, but of course with only two legs and not plastic. Similar in size; about 1.5 mm diameter, about 1.0 mm thick. Chris