RCA BA31-c replacing germanium transistors
« on: December 11, 2020, 06:18:12 AM »
Hi, I posted a while back about a set of four BA31-c modules I was working on, I have two working units and two non working units. I was unable to view a test tone on my scope between Q1 and Q2 so I figured Q1 was bad. I replaced Q1 but that has not solved the problem. I've attached a screenshot of a spreadsheet with voltage measurements for Q1 and Q2 on all four units. Any insights would be appreciated. I think I need to replace Q2 (2n404) on unit 1, I was wondering if anyone has any experience with the new NTE 2n404 transistors, are they a good replacement? I haven't really started to work on unit 2 the intermittent one.



Re: RCA BA31-c replacing germanium transistors
« Reply #1 on: December 11, 2020, 12:18:02 PM »
I have built them with the NTE subs and they work, although gain is a few db lower than the original preamps.


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