TLDR: I need to build a collection of NPN and PNP transistors(mostly medium powered complementary audio amplifier transistors) in order to avoid constantly ordering specific parts and waiting for them to arrive. Packaging and pin configuration is not important; what I am more concerned about are common combinations of Vce, hFE, Ic, Ipc, and Veb. What would be decent selection of five to ten sets of modern complementary pair replacements I might order to cover most of my needs?
Background: I am an engineer that recently got a fantastic job that is very laid back(I can work whenever I like) repairing vintage electronics, mostly amplifiers. The company had previously been buying old electronics from garage sales, flea markets, etc, and repairing any very simple problems they found(such as frayed power cords, replacing belts in cassette decks, or cosmetic issues) that didn't include any sort of electronic diagnosis. Any units they couldn't repair themselves, they started storing in the back warehouse several years ago, so there is now a huge backlog of items in need of repair. Since they had no technician previously, they had no replacement parts on hand, and had been discarding any non-working electronics that weren't worth any money non-working. Upon my arrival, I immediately put a halt to the disposal of non-working items in order to be able to later salvage parts, and in the last few months have sourced at least a hundred parts from the broken items we have since collected. I also built up a large stock of new capacitors, resistors, linear regulators, and low power transistors in order to facilitate my repairs in a timely manner. High powered output transistors are expensive, and will still need to be ordered on an as-needed basis, but I would like to order a selection of modern medium powered transistors that would be common replacements for older discontinued transistors. As an example, I once ordered many extra modern BD139/BD140 transistors when I needed one of each for a specific repair, and I have since used the extras to successfully replace several other older discontinued transistors of various part numbers. I would like to know if anyone with extensive repair experience would know the part numbers of the most commonly used modern replacements transistors, like the BD139/140s I have been frequently using.
