2SC1815 alternative for Mini Zen

[prezden]

Can anyone recommend an alternative for the Toshiba 2SC1815 used in the Mini Zen. It seems to be obsolete now.

Thanks

 

[sgrossklass]

Is this the "sensing transistor" Q3 here?

I used ZTX450s because I had some of these in my pocket. To substitute for the ZTX450, any NPN transistor with an hfe greater than 100 will work well. With the values as in the schematic diagram, the Q3 collector current is about 2.5mA and the Vce drop about 5V.

Sounds like most any of the usual suspects would work. If you're bound to Japanese transistor pinout, something like a 2SC2240 should work fine, otherwise you could use a plain ol' BC549B/C or BC550B/C.

 

[prezden]

Thanks for your response. Yes it is the Q3 although it's a bit confusing 😕
From the BOM it's listed as (Q1\Q2=IRF610 Q3=2SC1815).
The pcb has Q1L, Q2L, Q1R, Q2R.

 

[pilli]

What is confusing you?
The R and L suffix refers to the Right and Left channel.
In fact you have two copies of the circuit on the PCB.
Q1L and Q1R are both Q1's, so IRF610. Etcetera.


Pay attention to the fact that the C1815 has a "Japanese" ECB pinout, whereas the BC549 family are CBE.
If you are careful and insulate the pins, you can twist them into position.



_

 

[AndrewT]

....................Pay attention to the fact that the C1815 has a "Japanese" ECB pinout, whereas the BC549 family are CBE.
If you are careful and insulate the pins, you can twist them into position..................._

I generally find that when substituting a different pin out that insulating the middle leg with a tube from a solid core 0.6mm wire is sufficient.

I also find that rotating the device 90degrees and then bending one leg forward and another leg backwards gets the pin out to line up pretty well without risk of shorting legs.

Try not to bend legs at the package.
Use needle nose pliers to hold all three legs up tight to the package and bend the legs that protrude from the pliers. While still holding the device in the pliers offer it up to a copy of the PCB and make small adjustments to each protruding leg until a good fit is obtained. Now insert into PCB.

 

[prezden]

Hi pilli- I understand that L, R are right left what was confusing is that there is only one 2SC1815 in the list and space on the board for two on the board.
Andrew- thanks for the advice on bending the pins. I learned that the hard way on another project.

 

[sgrossklass]

Hi pilli- I understand that L, R are right left what was confusing is that there is only one 2SC1815 in the list and space on the board for two on the board.

The list is wrong then. You do need two of 'em, of course.

 

[prezden]

That's what I thought. Thanks guys!!