It is unclear what the SM means by D2, even sanyo doesn't mention an exponent type of suffix for that transistor and they are the manufacturer so I am pretty sure they mean 2SC930D. Perhaps they are enumerating the transistor of that series in the circuit if you have more than one 2SC930 in use. Tuner circuits are very finicky with transistors and I'm virtually certain that a 2SD930 will not work as a suitable replacement for a circuit where 2SD930D or higher is prescribed, otherwise they would have simply prescribed the non-suffixed version. I also mentioned previously that if you are buying your parts and they come from China, they will most likely be re(labeled) generics and not genuine transistors. This will be especially true if your replacement and originals do not look exactly the same with exactly the same fonts, etc. There is a reason why there's literally a million different types of transistors, the characteristics are carefully chosen for the application where they will serve. I'm not saying this is your problem for sure, but I've tried using the general non-suffixed version of transistors before in tuners and have not been successful in getting them to work in that circuit. You can try to find a transistor with similar characteristics and see if those will work but generally speaking, this is going to be a trial and error deal, and many replacements with similar characteristics might have different lead positioning so you may have to twist the leads to get them to work. As for whether "any" 2SD930D work better than a 2SC930, the specs state that the "D" version has 50% higher amplification. If you circuit needs it, then yes, it makes a difference, but again, it needs to be a real and not counterfeit one. I have purchased many transistors off eBay over the years and literally NONE of the ones I received tests with the correct characteristics in hfe, capacitance, etc. as compared to the datasheet. Even more disturbing is that if I purchase a batch (of 50, for example), tested individually, the results are all over the place, which in my opinion, renders them useless for circuits where specifications matter. They would only be useful for switches or other non-critical applications.
2SC930 Conv in the parts list is merely clarifying that the transistor is functioning as a mixer-converter. Ignore that portion.
2SC930 Conv in the parts list is merely clarifying that the transistor is functioning as a mixer-converter. Ignore that portion.