What part package is this transistor? - Page 1
Forum section: electronics / repair

author: LoveLaika
author_rank: Frequent Contributor
timestamp: January 25, 2023, 10:44:26 pm
content: I've been given a piece of equipment to repair. It's an inverter, an old one. It's kind of a long-shot, but the best I'm doing right now is finding parts to replace components with given the situation. One component that the inverter has is the(2S)C2721NPN transistor. It's old, but I was wondering what package is this? As you can see in the link, the leads are spaced 1.7 mm between each other. It doesn't seem like a TO-92 (at least based on what other transistor datasheets say), so I'm wondering if anyone knows here? It's one thing to find the same transistor specs (or better), but it all means nothing if it doesn't fit.I didn't put much detail about the repair job because I'm just asking about the transistor part. If I feel I need more help, I'll be more specific on the repair subforum.

author: coromonadalix
author_rank: Super Contributor
timestamp: January 26, 2023, 12:27:59 am
content: not sure if its a top166 or to126, but they normally have an holehum on very old website some of them where called x-19?even some other sites call them to220 loll

author: fzabkar
author_rank: Super Contributor
timestamp: January 26, 2023, 12:41:08 am
content: My ancient Towers Transistor Selector refers to the package as "X21" ... but it looks more like X19.This is the 1974 edition. Mine is 1985.https://www.bunkerofdoom.com/lit/semico/Towers-TowersInternationalTransistorSelector_text.pdf(page 130)

author: Kim Christensen
author_rank: Super Contributor
timestamp: January 26, 2023, 03:29:33 am
content: Unless the components around it are packed really closely to it, you should be able to fit an equivalent transistor with a TO-92 case in it's place as long as it also has the collector as the center pin.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: January 27, 2023, 07:57:21 pm
content: Thanks for the help. It might suck a little, but I think you're right after measuring the component holes. TO-220/92 might be able to squeeze in.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: January 27, 2023, 08:19:36 pm
content: Thanks for your reply. Darn old standards, can't hardly find any of these old parts anymore. Looking at a rough search,TO-126might just fit, if only barely. Though, it's all just a shot in the dark right now.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: January 27, 2023, 08:22:24 pm
content: Thanks. Yeah, my transistor does look like the X19. Wish I could find these packages nowadays. Doing some research and some leeway, I think maybe (just maybe), a TO-92 or TO-126 might just fit the spot, even if the fit is tight.That's a fascinating resource. It looks handy.

author: fzabkar
author_rank: Super Contributor
timestamp: January 27, 2023, 08:43:40 pm
content: I'm wondering whether those "Xnn" packages are codes that Towers created for his book rather than actual manufacturer codes.

author: Kim Christensen
author_rank: Super Contributor
timestamp: January 28, 2023, 01:03:00 am
content: Quote from: LoveLaika on January 27, 2023, 08:22:24 pmJudging by the power rating and other specs of the 2SC2721, you're more likely to find a closer electrical match in the smaller TO-92 package vs the larger TO-126. Plus the leads on the TO-92 are smaller and easier to bend to fit the PCB holes than the larger stiffer leads of a TO-126. Depending on the application, something like a KSD1616A might work.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: February 02, 2023, 02:38:11 pm
content: Thank you. I'll consider it. Unfortunately, after removing the few transistors on my equipment, independently testing them verified that they worked from what I can tell. So, I'm back to the drawing board, trying to see what to do next.