2019-02-01 Raytheon 1N128 Germanium Diodes

Link left on FB group Building Transistor Radios

Someone in the group mentioned a source of crystal radio parts, Small Bear Electronics and linked to their website. I found that they had some germanium diodes, Raytheon 1N128, and they showed the reel of them, so I thought my chances of getting factory parts would be better if the diodes were still in some form of packaging. So I ordered a dozen and a half at $0.00 apiece. The next week I received a bunch of 1N128 diodes from Small Bear, but all of them were loose and marked with the letter T. I’ve seen that before, it was the symbol for Transitron, not Raytheon. I emailed the company and asked to exchange them for Raytheon diodes, or else I asked for a refund if Raytheon diodes were not available. The guy apologized and said he would send them out. A week later I received the package with the real Raytheon 1N128 diodes, which still were on tape.

Today I took the time to check some of the diodes out. I wired a AAA cell, a 100k resistor and the diodes in series and connected a DMM across the 100k resistor. I connected the diodes in reverse, and I expected to read a small leakage current through the germanium diodes. I connected one of the Raytheon 1N128 diodes and found that it had about 25 microamps leakage. That seemed okay. I connected one of the Transitron 1N128 diodes and I saw no voltage across the 100k like the diode was open. I reversed the diode and it gave the same open reading of zero. I could get the DMM to give a fraction of a microamp reading by squeezing both leads of the diode with my fingers, so I knew there was nothing wrong with the test circuit. I used a sharpie marker to blacken the diode and then I tested another diode. It was also open, an insulator, not a semiconductor. I continued testing and found only a few that were somewhat semiconducting. One seemed to be mismarked, it was backwards. Another was about as semiconducting one way as the other, but most of the diodes were just insulators. I could understand it if I got one bad one out of the whole bunch, but in this case only one was somewhat good, and all the rest were bad. These Transitron 1N128 germanium diodes were floor sweepings or factory rejects – they were all useless. Needless to say I will not be making any more purchases from this company.

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