Silicon replacements should work fine; I would try the TIP30 or other low current and slow power transistors like the BD234/BD236/BD238. The only thing I would worry about is oscillation during switching if the replacements are too fast and that is something I would check with an oscilloscope by monitoring the collector waveform.
The transistors operate in saturation so the bias change will be insignificant; the higher Vbe of silicon will lower the frequency by about 3%. I could not find any data on the GA2817 shown in the parts list. The minimum Vce in the circuit is double the supply voltage. I think Ic is below 100 milliamps. On Mon, 6 Jun 2016 12:25:32 -0400, you wrote: >Hi Lou, > >It's normal for some leakage in germanium transistors. Do you have a >curve tracer? >If you change them to Si you will have to re-bias them (i.e. R207_8). >The 84 Hz may change also, might have to adjust C203. >But should be possible. > >Dallas > > >On 6/6/2016 7:33 AM, Lou Amadio wrote: >> For Dallas Smith >> Thanks for the info. It is in keeping with the original design. >> My 845AB 15v supplies are currently down and I suspect the germanium >> transistors around T202 may be leaky?. >> Am thinking of replacing them with Si transistors. Your thoughts? >> Regards, Lou _______________________________________________ volt-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
