Try searching eBay on the subs you find and you might get a set for 10 bucks. The higher 2N numbers listed are newer manufacture parts. There may be other cross ref lists online, this is the first one google brought up. I used to do this years ago using paper cross reference books when I worked in a TV and sound shop to find suitable subs using parts I had on-hand. ![]() Go to this website and browser search for '121' (CTRL F) and you will find several 2N numbers that the NTE-121 will replace. I guess they're necessary for stepping down the high-voltage from the tubed stages. At first I thought they were output transformers. There are two transformers driving the output stage. You also asked about a transformer driver. I figure the NTEs are going to run me $175 large, so anything original that costs less than that would be OK I guess. Also, I know these exact transistors were used in other Fisher chassis of the same era, so I'm hoping one will show up on Ebay for a reasonable price. I just wish I could somehow find he actual specs on these original ones so that I could maybe get lucky and find some old stock comparables. So yeah, I wondered about that also, but chalked it up to an undocumented design change somewhere along the line.Īnd yes, they are germainum, as are the NTE 121s which cross reference. The schematic/parts list indicates 35524 in four of the eight sockets, but all eight of mine are clearly marked 35144. So, I guess my questions to the group are:ġ) Does anyone know which RCA type the TR35144 part number actually corresponds to? You know, 2N.something or another?ģ) Would NTE transistors in the output stage really be that bad, or is their reputation a result of undeserved online lore? I'm sure they're an RCA type 2N something or another, but I can't find anything to tell me which type that actually is. Problem is, despite searching online and through a 300-page RCA semiconductor databook from 1966 at the local library, I can find no reference whatsoever to actual specifications based on the "TR35144" number. What I'd like to try to do is find some NOS or even straight-up used transistors that would have specs close enough to the original parts so as to be a decent substitution. Of course, the NTE option is expensive ($22 each x 8), not highly regarded among the online communiity for some reason, and might not even be the optimal replacement, purely from a specification standpoint. ![]() From everything I've read online, the "TR35144" RCA part number printed on the parts and in the service manual is cross-referenced to NTE-121. I'm looking at a plastic baggie full of shorted output transistors from my Fisher 690-A 'hybrid' chassis (tube pre-amp/driver, transistor output), and wondering what the best strategy for replacing them might be. I posted this in the 'Fisher' forum, but got to thinking this forum may be another good alternative.
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