Author Topic: Help me identify part  (Read 884 times)

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Offline DarkZeroTopic starter

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Help me identify part
« on: July 12, 2019, 08:33:44 am »
When i search for this part number i get no meaningfull results guess its a old transistor but i need specs in order to replace it
 

Offline capt bullshot

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Re: Help me identify part
« Reply #1 on: July 12, 2019, 10:12:02 am »
There's no BCxxx transistor starting with two digit number, so it might be a BC174 (but these don't have the -40 suffix, rather A/B/C), so it isn't the BC174, same with the BC274, then we have a BC373-40 (but no BC374), no BC474, no BC574, 674, 774, 874

There's a BCX74-40 made by Siemens, I guess this one is right, since there's some kind of X top left. Normally transistors of this vintage are marked with the full type number, just a bit scrambled ;)

So its data: NPN, 45V Uceo, 800mA, 625mW,
-40 indicates beta in the ballpark of 400.
BCX types are usually fast switching bipolar transistors.

http://www.rsp-italy.it/Electronics/Databooks/Siemens/_contents/Siemens%20Transistors%201980-1981.pdf
« Last Edit: July 12, 2019, 10:13:34 am by capt bullshot »
Safety devices hinder evolution
 

Offline DarkZeroTopic starter

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Re: Help me identify part
« Reply #2 on: July 12, 2019, 04:47:24 pm »
Let me give u some more info my dentist friend that does my teeth for free has these modules that die yearly that drive a pump now the service guys plugs in a new one and charges him a small fortune so he gave me couple of non working ones and i found that on all 5 this transistor is shorted so the malfunction repeats. I want to try and repair it so i can say thx to my friend for fixing my teeth free of charge. Besides this electronic module looks super simple.
 

Offline Rigolon

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Re: Help me identify part
« Reply #3 on: July 12, 2019, 06:06:11 pm »
I believe capt bullshot is right, since that symbol on the right side of the X mark was used by Siemens back then.

I would try getting some equivalent transistors and using them to see if it's a match.
 


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