fisher: Replacing 2n2614 germanium transistor with a Russian MP42B
I am about to restore a Fisher 600T stereo receiver
Most of the transistors are germanium, and the ones that are available out there in the market, are leaky and unstable
Afer reading and learning about Russian germanium transistors, and their availability, i would like to replace afew of the transistors that are shorted or very weak
Has anyone used a MP42B germanium transistor to replace 2N2613 and 2N2614?
МП42Б: Uce max = 15V, hfe = 45÷100, fmax = 1MHz case simillar to TO39
2N2613: Uce max = 30V, hfe >100, fmax = 4MHz, case TO1
2N2614: Uce max = 40V, hfe >100, fmax = 4MHz, case TO1
Russian transistor has much smaller max Uce voltage, lower gain and lower maxium frequency and are phisically bigger than 2N. You can try to use МП42Б if circuit voltage is lower than 15V and they work in DC or AF circuits
What about using a MP40A?
МП40 has much lower h21. It may works or not, depends on used application. Try МП20 (for AF and DC only) or ГТ321Е (also for IF and HF)