UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Rock-Ola 40218-1-A Transistor Amplifier Problems

Vakito227 · 25th Jan 2020, 6:53 pm

I now have a 2N2148 to replace the dead 2N2147, Many thanks to Tim for this!
I'm not too familiar with transistors but one thing has flagged up which I am concerned about. On the diagram there is 35v going into the collector and 45v coming out of the emitter. The maximum collector-emitter voltage on a 2N2148 is 40V compared with 50V for a 2N2147. Will this be a problem?

PJL, I will attempt to follow your guide although I don't want to risk replacing the driver transistor and switching it on, even for 5 seconds and risk it destroying this 2N2148 I now have. Are there any tests without the driver transistor fitted that I can perform first just to guarantee it will not destroy it?

Thanks
Peter

25th Jan 2020, 6:53 pm	#27
Vakito227 Hexode Join Date: Apr 2016 Location: Yeadon, West Yorkshire, UK. Posts: 251	Re: Rock-Ola 40218-1-A Transistor Amplifier Problems I now have a 2N2148 to replace the dead 2N2147, Many thanks to Tim for this! I'm not too familiar with transistors but one thing has flagged up which I am concerned about. On the diagram there is 35v going into the collector and 45v coming out of the emitter. The maximum collector-emitter voltage on a 2N2148 is 40V compared with 50V for a 2N2147. Will this be a problem? PJL, I will attempt to follow your guide although I don't want to risk replacing the driver transistor and switching it on, even for 5 seconds and risk it destroying this 2N2148 I now have. Are there any tests without the driver transistor fitted that I can perform first just to guarantee it will not destroy it? Thanks Peter