hfe

I have been fixing A sansui 9090db for a while now,driver board ,power supply are done unit is re-capped ,keeps going green then maybe a minute or more then goes into protection.my theory is it had weak mj21194 g's hfe was 41,46,45,53,the 93's were in the 80's hfe zone,I've replaced them...

So I’m testing some germanium transistors I just got to try to get some matches. One of them read 239! Is there something wrong here or is this a super transistor? Also while we’re on it. How close should 2 transistor hfe numbers be to be considered matched?

Without going into calculus, how important a role does the gain of BJTs play in the performance of an amplifier? I ask because I’m in the process of restoring a Harmon Kardon 330c and I’ve read in other threads that there may be “noisy” transistors in it. I don’t have golden ears, more like...

Hi there, I hope someone can help please. I'm restoring an HK430 twin PSU receiver and appear to be falling at the last hurdle. There was crackling and switch/pot noise so after some consultation here, I have replaced all the angular 2SC458, 2SC1344 & 2SC1345 transistors with new KSC1845 (from...

I am following the routine replacement of old 2SC1345 transistors with KSC1845FTA in the control board of a Kenwood KA-5500, but I can’t find the data sheet for the E model of the 1345. They are the ones with the “outhouse” shape, and they have blackened legs up to the transistor itself, so they...