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Coral Stentor 100 help!

Discussion in 'Amps and Cabs [BG]' started by J_T_Heck, Dec 26, 2013.


  1. J_T_Heck

    J_T_Heck

    Dec 26, 2013
    Hi, First post, helping a friend. Trying to repair the amp and I have a schematic. However, the transistor numbers don't make sense. I cannot figure out what a "9138" or a "3155" really are. Anybody been down this road? I think the 3155 is bad, since it fails on a transistor tester as Si or Ge, PNP or NPN.
    The schematic shows the 3155 as PNP, and I can probably guess on acceptable parameters for the transistor specs, and finally, since the transistor was made in 1967 (mfgr date code), I'm guessing it is Germanium. So, I could hope I'm right and find something close, but it could get costly. Any ideas from the more knowledgeable folks?
    Thanks
     
  2. J_T_Heck

    J_T_Heck

    Dec 26, 2013
    Hi, thanks for the reply. Unfortunately, the specifications for the case don't make sense. The transistor I have is a TO-3 case, all metal, screws to hold it down, typical power transistor. The 2N3155 is (apparently) not that case style. The transistor I have does not even have a manufacturer, although the date code is 6722, and there is also a small 466 on it as well.