New find on bogus bipolar transistor! (SGSIF461)

[Jason D.]

Got a few of those and those ran hotter and they blew in PTK169
chassis after hour or so. They was from home-brewed kits that
supplier put together for very good price (about 10 each for kit of:
transistor, three caps (two were wrong types and total correct rebuild
requires four caps, two of them 39uF & 15uF very important), IC is not
fake through because I nut-cracked that.

So got the RCA OEM version and now SMPS's heatsink runs cooler and is
fine.

I saved both blown OEM and fakes SGSIF461 transistors and cracked
them(1). The fake was plated (white) copper plate & had white silicon
splat over the die.
OEM or true ones were unplated copper (shows shiny copper) plate and
bare die assembly cast in black package.

This cost me 2 callbacks on same unit because of this.

Cheers,

Wizard

1. Cracking them, fake transistor was very easy & die intact, I was
surprised. The OEM put up lot of fight before package finally gave way
with loud "CRACK!" and shattered the bare die.

 

[El Meda]

1. Cracking them, fake transistor was very easy & die intact, I was
surprised. The OEM put up lot of fight before package finally gave way
with loud "CRACK!" and shattered the bare die.

That´s because the epoxic of the package does not adhere to the white
goo that covers the silicon die. I have pictures of many open fake
transistors on this page:

http://transfal.tripod.com/

 

[Jason D.]

That´s because the epoxic of the package does not adhere to the white
goo that covers the silicon die. I have pictures of many open fake
transistors on this page:

http://transfal.tripod.com/

Thanks,

I have seen your website, babelfish only translated fixed number of
words. Would be nice to post another website in english.

This fake transistor actually is slightly larger die than original
one. Strange.

The white glop is silicone glue or silicone-based potting.

Silicon is correct for the primary material used in semiconductors.

I wanted to add new finds to others so they can kee a eye on that.

Cheers,

Wizard

 

[El Meda]

I have seen your website, babelfish only translated fixed number of

words. Would be nice to post another website in english.

It's a good idea. I'll do it in the next future.