Цитата:
WA7KKP 01-09-2007, 08:13 PM
Germanium transistors check the same as any other transistor, if you`re using an ohmmeter for junction forward/reverse leakage. You`ll find that Ge transistors, especially the large power handling types, can be quite leaky and still work fine.
If they fail, they usually have an emitter-collector short, and you`ll know real quick when that happens -- fuses blow with a vengeance
Silicon transistors are much more rugged, and resilient to overloads and voltage spikes than Ge.
The squeal you hear is those transistors acting in a multivibrator circuit, changing 12v DC into a square wave AC that is transformed up to the necessary plate voltages you need to operate your NCX-3. If at full 13.8v DC input the supply draws more than an amp or two with NO LOAD, or 20 amps under full load, then you`ve got problems.