"exact" replacement for D357 transistor

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Nounours18200

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#1
Hi,

I currently restore an old Sansui AU-919, in which a D357 transistor looks damaged.

What replacement do you suggest ? Of course, I am loking for a drop-in replacement...

I have found this info: D357 - 110V, 800mA, 10W, B=100 min

Thank you !

P.S.: I suspect that a B527 could also be damaged, but not sure for the time being.
 
#2
Nounours18200 said:
Hi,

I currently restore an old Sansui AU-919, in which a D357 transistor looks damaged.

What replacement do you suggest ? Of course, I am loking for a drop-in replacement...

I have found this info: D357 - 110V, 800mA, 10W, B=100 min

Thank you !

P.S.: I suspect that a B527 could also be damaged, but not sure for the time being.
Click to expand...

What does "looks" mean?

What does "suspect" mean?

Have you *measured* them?

Looks means nothing, unless they are cracked smoking covered in their own soot.
 
#7
What does "looks" mean?
What does "suspect" mean?
Have you *measured* them?
Click to expand...

Not necessary to perform any measurement: the problem does not come from the transistor itself, but from the glue used 40years ago to fix the capacitors on the PCB.
This glue oxydizes the pins of the surrounding parts, and destroys these pins.
The only possible cure is to remove the glue from the PCB and then replace the damaged parts.
The pins of the D357 transistor are oxydized and therefore I have to replace the D357...

@lcsaszar : the links gives the BB237 as the only equivalent transistor. Nut i have to verify that the gain is identical.


Looks like your basic run of the mill jap driver transistor. KSC2690 is what’s available these days.
Click to expand...
The KSC2690 does not appear in the Icasar link

I also look in my stock if I have his , otherwise littlediode has on the bay ....
Click to expand...
I have looked at the Littlediode shop on eBay: they do not list the D357 in their available parts...

Thanks for your replies, although I am not sure that I can safely use the BD237 as a drop in replacement of the D357..
 
#9
Yes, I have seen my share of corroded transistors. Sometimes they still work, but in all cases are a reliability risk. I’d replace it if I’m doing anything to the amp. It looks like your choices are pay a ridiculous $10 each for what might be a real one, go on E-bay and get a fake which may or may not work, use a BD23x or MJE340 which will probably work (but fT is low), or use a modern part like KSC2690 or something equivalent from Toshiba or Sanken. It is just a 10 watt moderate gain driver and doesn’t have to be anything special. I just use whatever the current production drivers happen to be - they go obsolete and are replaced by new types every couple of years.
 
#11
Nounours18200 said:
Not necessary to perform any measurement: the problem does not come from the transistor itself, but from the glue used 40years ago to fix the capacitors on the PCB.
This glue oxydizes the pins of the surrounding parts, and destroys these pins.
The only possible cure is to remove the glue from the PCB and then replace the damaged parts.
The pins of the D357 transistor are oxydized and therefore I have to replace the D357...

@lcsaszar : the links gives the BB237 as the only equivalent transistor. Nut i have to verify that the gain is identical.



The KSC2690 does not appear in the Icasar link


I have looked at the Littlediode shop on eBay: they do not list the D357 in their available parts...

Thanks for your replies, although I am not sure that I can safely use the BD237 as a drop in replacement of the D357..
Click to expand...


Here is the link to ebay and yes you are wrong it is 2sd357 and not bd357

2SD357 Transistor Silicon NPN - CASE: TO220 MAKE: Mitsubishi | eBay
 
#12
Thank you so much guys for all your replies !

The Littlediodes devices are a bit expensive (10€ for one transistor...), and as said above:

"BD239C is also listed as a replacement, among others... "
and is available from Mouser (a supplier where I regularly place orders, so I could group with my next order...).

The BD239C datasheet exibits some differences with the 2SD357, like "DC current gain=40 @.2A", whereas the 2SD357 is supposed to have a 55 gain @ 0.2A

Could it be a problem ? (my knowledge is not sufficient in this area...)

Thanks again !
 
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