The problem is most likely to occur in those transistors used as an emitter follower; these are mostly used as output stages on some of the pc boards that drive a potentially long shielded cable. You can identify an emitter follower by the fact
The problem is most likely to occur in those transistors used as an emitter follower; these are mostly used as output stages on some of the pc boards that drive a potentially long shielded cable. You can identify an emitter follower by the fact that there is no resistor in series with the collector, and the output comes from the emitter. Furthermore, in most cases the base of the emitter-follower stage connects directly to the collector of the transistor before it.
I have not run across this problem in my own organ, but I have seen it in emitter follower circuits that have been breadboarded on the lab bench. I suppose Schober ran across this problem when they upgraded the RV-3 Reverbatape to an RV-3a, which used silicon rather than germanium transistors. They apparently found that transistor 118 (an emitter follower) sometimes oscillated, because they added a 100 pF capacitor, connected from the emitter to the collector of the transistor, with instructions to solder the capacitor under the board using very short leads. I suppose it might be a good precaution to do so with other em