Should i trust this substitution?

[throbscottle]

One of the BSX20 transistors has failed in my Cossor CDU 150 - the final part of the fault it had when I got it. Looking for a replacement I keep coming across transistors sold as BSX20 but in the specs it says "device marking 2N4401". This seems dodgy to me because these listings also state the case as TO18, but if I look for data on 2N4401 it is specified as TO92 and appears to be a bit more general purpose - in particular it has a much longer storage time and half the transition frequency. Real BSX20's are expensive (and I think they might not be made anymore), these ones are much cheaper.

Could someone enlighten me what is going on here? Or suggest a better substitute?

I put in a BC549 temporarily as the "least worst" tranny for the job in my junk box so at least the 'scope works now.

 

[mvs sarma]

One of the BSX20 transistors has failed in my Cossor CDU 150 - the final part of the fault it had when I got it. Looking for a replacement I keep coming across transistors sold as BSX20 but in the specs it says "device marking 2N4401". This seems dodgy to me because these listings also state the case as TO18, but if I look for data on 2N4401 it is specified as TO92 and appears to be a bit more general purpose - in particular it has a much longer storage time and half the transition frequency. Real BSX20's are expensive (and I think they might not be made anymore), these ones are much cheaper.

Could someone enlighten me what is going on here? Or suggest a better substitute?

I put in a BC549 temporarily as the "least worst" tranny for the job in my junk box so at least the 'scope works now.

depending on the max frequency needed as per the location of usage, you can perhaps think whether you can use 2n2219 in TO18 package.

 

[dr pepper]

I think I have some bsx20's, well I have a drawer for them, I'll check when I get home.
I got them as replacements for 4 pin rca3018's in a 60's plymouth car radio, I think they were used in the local oscillator.
Doesnt the bsx20 go to silly frequencies?

 

[jls28]

A good replacement for bsx20
is 2N2369, 2N2369A, PN2369 (to92) ...

 

[throbscottle]

Hey jls28, welcome to the forum!
2N2369A looks like a good substitute but I will have to check the collector current! (And at least with TO18 you always know which leg is which )

Sarma - looks like the 2N2219 isn't much improvement on what I've put in, but thanks for the suggestion.

Dr Pepper - yes, it's transition frequency is 500MHz and it's designated as a high speed switch. If I could buy one off you that would be ideal...

 

[dr pepper]

If I've got some in the drawer throbs you can have one, other people not neccesarily on this forum have sent me stuff in the past so its only right if I do the same.
I will be back home shortly I'll have a look.
I didnt know they went to uhf frequencies.

 

[dr pepper]

Hi throbs.
I searched for the trannys, guess what when I checked the number, 2n2222.
I got duped just like you.
Next time I go to the supplier (cpc) I'll bring it up with them.

 

[mvs sarma]

I humbly feel that let the scope work and think of any replacement only when the device fails.

 

[throbscottle]

I found a seller of genuine BSX20's reasonably priced so got a couple of them so I have a spare.
Sarma, I would normally agree with you, but I have quite a bee in my bonnet about this scope now. I'll be fitting one of the new tranny's when I've got a proper replacement for the ch2 invert switch (so I can do both together) - again I've been "letting it work" with an improper replacement, but it annoys me like crazy knowing it's in there!

 

[dr pepper]

Excellent glad you found some.
I just repaired my sig gen, it had 2n4036's in it, I've bodged it with a bc327 and it too annoys me.

 

[throbscottle]

Glad it's not just me!