Sony electronics part

On one of my older Sony amps (1002HX to be exact) there is a FET with the number K2421. I know the part is bad but I have not been able to find that number in any of the catalogues I have. Does anyone know what a comparable part would be for this? It goes on board MTAJ30N06HD (Sony # 8-729-030-73). Any help would be appreciated.

Unless it’s a bulb, I can’t help much.

No, not bulbs at all. FETS! As in field effect transistor.

Sorry. I had a post but my browser crashed. So I don’t have all the nice info like I did in that one …
anyway, you should be sure it is what you think it is. Are you working off a schematic, or from a service manual, or just by inspection? I wouldn’t want anything bad to happen.

But I had found a few parts at ‘chipdocs’ with ‘242’ in them; there’s a few K242x’s which are N-channel power & switching FETS. There was a 2421 made by a company called Sanken, which is a 40-A, 60-V or so part, IIRC. I forget what package, but I’m figuring you’re looking at a TO-220 in there, right?

Maybe you can’t find it because you’re not using the full device number, which is 2SK2421. I don’t have access to Sony’s National Parts Center at work (because I don’t work for them any more!) but I think I still have access from home & can get the manufacturer’s part number if that will help.