Re: Strange transistor

Thanks for the input.  It is a D70 which crosses to an ECG 181 audio power
amp xsistor --- it is used in a car audio system.



-----Original Message-----
From: Tesla List <tesla-at-pupman-dot-com>
To: tesla-at-pupman-dot-com <tesla-at-pupman-dot-com>
Date: Tuesday, June 08, 1999 11:31 PM
Subject: Re: Strange transistor

Original Poster: "Reinhard Walter Buchner" <rw.buchner-at-verbund-dot-net>

Hi Doc R,

> Original Poster: "Dr. Resonance" <Dr.Resonance-at-next-wave-dot-net>
> I'm trying to cross reference a strange transistor and can't find any
> crossovers.
> It is stamped D70-9360 and appears to have an automotive application.
>It checks as an NPN transistor.
> Anyone have any ideas??

If it is a Japanese transistor, try adding 2S (Japanese coding = xS;
where x is one less than the number of leads (in this case 3) and
S simply means silicon) in front of the number, although I have
yet to see a transistor with that suffix (9360). Try 2SD(1)70(0).
The "D" in this case would mean high frequency switching transistor.
9360 would seem like a date code (but then, there is no 60th week
in a year).

What application did it come from (i.e: used in)? If it was an
automotive application, this might be a Ford, GM, Chevy, Mopar,
etc. electronics division number (i.e: Chevy & GM would be AC-
Delco, etc) number. If so, your ONLY hope will be to contact an
authorized car service dealer, that can decode the number.

If it is still funtioning, I would simply measure the beta and
find a substitute that will withstand peak voltage and current
in the circuit it will used in. Check to see if there is a freewheel
diode in the C-E Junction. A number of switching transistors
also have a 50-200 ohm resistor in the B-E junction
(measurable, too). If it is a HOT or the main switching
transistor in a SMPS, you will have to consider the parasitic
capacitance, etc. And this is where it starts getting a little

I really hate it when manufacturers think its funny to mislead
(and more or less force you to have it repaired) you with
some strange combo of numbers. Even more aggrevating is
when companies (esp. Japanese firms) file off the IC number
and their only comment is: "Well son, send it in, because we
arenīt allowed to give away company secrets" (read: the
schematics).  Quite a few european companies are known
for this tactic (arrrrghhh ;o(((!!!!).

My 2 cents: If I buy a product (and pay for the manufacturing
and developing costs), then I have a da.. right to get the
according schematics (they are patend protected anyway). I
never understood why they make such a fuss about it. It
doesnīt protect them in any way. If I had a "job" as an
industrial spy (I donīt ;o)), I would simply buy a prototype
and reverse engineer the schematics. I have noticed that in
the U.S, manufacturers are much more willing to help (with
schematics and info), than european companies are.

Sorry for the ramble, but these are the kind of things that
can get me "ticked off".

Anyway, I hope it helps in some way.

Coiler greets from Germany,