Back in 1968 the typical drivers for 2N3055's were the 40361 and 40362. I suspect these were Quad's 38495/6 (although shipped with a heatsink flange). They might have been the 40634/40635, which seem to be uprated 40361/2.
The BD139 and BD140 can be used as replacements but would need some refitting to accommodate.
Candidates for TO-18 devices back then rated at ~65V+ were not common. The BC107 types could only manage 45V. Perhaps a selected BC107 for 65V? The BC477 was rated at 80V but I think it was introduced later. Replacements could be 2N5401/2N5551 though some have suggested BC546/BC556 but at 65V that is marginal. The MPSA06/MPSA56 are obsolete, as are the ZTX304/504 which were suggested as options too.
Does anyone know what the U17219/U17229 devices were based on?
The BD139 and BD140 can be used as replacements but would need some refitting to accommodate.
Candidates for TO-18 devices back then rated at ~65V+ were not common. The BC107 types could only manage 45V. Perhaps a selected BC107 for 65V? The BC477 was rated at 80V but I think it was introduced later. Replacements could be 2N5401/2N5551 though some have suggested BC546/BC556 but at 65V that is marginal. The MPSA06/MPSA56 are obsolete, as are the ZTX304/504 which were suggested as options too.
Does anyone know what the U17219/U17229 devices were based on?
TO-126 good for a little more than that with a heat sink. Even a little one buys a lot, and TO-5’s were only good to a watt without one. And are more difficult to heat sink. Maybe, back in 1974 TO-5’s with one of those flanges welded on were available in every dime store on the planet, but in 2024 they’re a little hard to come by.
That’s about the only thing you can use on a naked TO-5. Good luck getting an actual flanged TO-5 without a working flux capacitor and some plutonium.
TO-5's were best mounted with a steel clamp over the top onto an aluminium heatsink directly (insulated from the rest of the world, obvs.).
Recently drilled a steel "repair" washer, 1 inch approx. dia. for M8 screws with two 2mm holes for clamping for that purpose. Contacting the header underneath worked better than the small heat clips you push on.
But sometimes it is easier just to rejig the whole thing cfor BD139's etc.
Recently drilled a steel "repair" washer, 1 inch approx. dia. for M8 screws with two 2mm holes for clamping for that purpose. Contacting the header underneath worked better than the small heat clips you push on.
But sometimes it is easier just to rejig the whole thing cfor BD139's etc.
The die is at the bottom of the package. Heat sink connecting there is really the right place, but oh so inconvenient. That’s why RCA made those V1 and V2 versions of many of their house numbers so it had a decent heat sink permanently attached. Nobody gave any thought to what happened 20, 30 years later. I guess they figured that silicon transistors last forever. Problem is that an overloaded output tranny can take the driver out with it……