![]() ![]() They cost more because they have to maintain all the cross database, plus each part is packaged and labelled. I try to steer techs away from it, and cost is a major reason. But if you walk into a local parts store, then you are paying for the convenience. If you need to order a part, there is little reason to pay for NTE when you can just as easily order the ral part. ![]() Your electronics store signed on to NTE as a franchise and your entire line of needs was covered. NTE and the others was a way to have a genreal replacement line without having to stock a lot of types from a lot or manufacturers. I don't doubt SK was hard to find by 1990, the line folded. About the only reason I do that anymore is to find the price on an NTE part to compare to the real part, when suggesting someone avoid NTE. I have one a few feet to me left right now, but it is usually faster just to punch up the NTE web site as I sit here to cross something that it is to go grab the book. ![]() I have always had paper NTE books on my shelf for reference. In fairness, they don t claim equivalence necessarily, they claim their part number will work in place of the original in most cases. SK3024-128 datasheet and application note, data sheet, circuit, pdf, cross reference | Datasheet Archive Unfortunately, the parametric curves of old parts don't get published often but my inclination is now to go with 2N3019 as a replacement. Here are some datasheet links for reference. Fine, but they then spent the rest of the sizable manual tabulating them as substitutes for any type you could dream up! In another example of simplistic advice, I first laid eyes on Tandy's Radio Shack transistor manual around 1980 and saw they stocked only about 30 general purpose types. On the subject of NTE equivalent lists, how could they rate their NTE128 as an equivalent? Agreed Harleyjon, you have to ask that question. Perhaps these were just selected standard parts again. The 80V Vceo seems unnecessary but if it also suited higher power models, you could understand just the one part being specified since 2N3053 is only a 40V Vceo. This seems close or at least a good one-size-fits-all solution. With the reference SK3024/128, I was able to dig a bit more and cross-reference the datasheet with some dubious ones on the web. Thanks folks, I appreciate your help in looking up this ancient relic. The NTE drivers have b-e capacitors installed, to cut the slew rate. The 5 digit transistors on right channel are working on into the 21st century, without the TIP mod b-e capacitors. These days I would use MPS8099 for the input transistor and TIP31C TIP32C for the driver transistors. This was in 1990 when one drove to a store to buy transistors. I replaced the 5 digit RCA TO5 transistors on one channel of my ST120 with NTE249 for the input, and NTE49 NTE50 for the drivers with the heatsinks. The 5 digit RCA TO3 transistors in my 1970 build dynakit ST120 weren't in the catalog either. That is npn Vceo 80 Pt 7W, Ic 1a, Hfe typ Vce 10 Ic. The 1986 RCA SK catalog shows the 36643 as equivalent to SK3024/128. The SOA is flat Ic 7 A til the DC line drops Vce 6 until it ends Vce 40 & Ic. 5 Ic 0 <80 pf, thetajc 35 degC/W, thetajfa 175 deg/W. 2n3053 specs, Vceo 50v w/ base open 100ma, Ic. I've got the RCA Power Transistor databook SSD-204c, dated 1975. ![]()
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