NiCd power tool blown circuit

T

Tibur Waltson

Guest
I unscrew and open up a 12V cordless drill and spots what looks like a transistor.
Hmm..I decide to hook up a 12V 2-amp battery charger into the drill and see what
happens, unfortunately in reverse polarity. The moment I press the "on" button on
the drill I see a flash-bang and smoke from the transistor. I thought, "How am I
going to find a replacement part?" Does anyone know what other transistor is
compatible with this one? Or, any reverse polarity preventive advice? - as this
is not my first case.
TIA
Tibur
 
"Tibur Waltson" bravely wrote to "All" (03 Jan 04 07:59:00)
--- on the heady topic of "NiCd power tool blown circuit"

Is this a troll? No maker, model, nor transistor id, etc? ;-)

TW> From: "Tibur Waltson" <Toush@hi.com>

TW> I unscrew and open up a 12V cordless drill and spots what looks like a
TW> transistor. Hmm..I decide to hook up a 12V 2-amp battery charger into
TW> the drill and see what happens, unfortunately in reverse polarity. The
TW> moment I press the "on" button on the drill I see a flash-bang and
TW> smoke from the transistor. I thought, "How am I going to find a
TW> replacement part?" Does anyone know what other transistor is compatible
TW> with this one? Or, any reverse polarity preventive advice? - as this is
TW> not my first case. TIA
TW> Tibur

.... High voltage can give a dangerously uncomfortable discharge.
 
Sounds to me like you should go play with some guns, so the world will have
one less idiot to deal with.
"Tibur Waltson" <Toush@hi.com> wrote in message
news:88eb56e37fa319bc7c6444a0ae33247a@news.bubbanews.com...
I unscrew and open up a 12V cordless drill and spots what looks like a
transistor.
Hmm..I decide to hook up a 12V 2-amp battery charger into the drill and
see what
happens, unfortunately in reverse polarity. The moment I press the "on"
button on
the drill I see a flash-bang and smoke from the transistor. I thought,
"How am I
going to find a replacement part?" Does anyone know what other transistor
is
compatible with this one? Or, any reverse polarity preventive advice? - as
this
is not my first case.
TIA
Tibur
 
Tibur Waltson[Toush@hi.com] said this in sci.electronics.repair, at Sat, 03 Jan
2004 07:59:00 GMT, in article
<88eb56e37fa319bc7c6444a0ae33247a@news.bubbanews.com>. I can prove it. And thus I
reply:

I unscrew and open up a 12V cordless drill and spots what looks like a transistor.
Hmm..I decide to hook up a 12V 2-amp battery charger into the drill and see what
happens, unfortunately in reverse polarity. The moment I press the "on" button on
the drill I see a flash-bang and smoke from the transistor. I thought, "How am I
going to find a replacement part?" Does anyone know what other transistor is
compatible with this one? Or, any reverse polarity preventive advice? - as this
is not my first case.
_I think_ this may be a power transistor. Try using a 2N3055 for a start.

BTW, is the OP trolling? No model/transistor markings were given.


--
ChaosŽ - posting from Brazil
Please ask for e-mail address.
 
"Chaos Master" <ask_for_the_address@yahoo.com> wrote in message
news:MPG.1a610a61edac60059898ef@news.cis.dfn.de...
said this in sci.electronics.repair, at Sat,
03 Jan
2004 07:59:00 GMT, in article
88eb56e37fa319bc7c6444a0ae33247a@news.bubbanews.com>. I can prove it. And
thus I
reply:

I unscrew and open up a 12V cordless drill and spots what looks like a
transistor.
Hmm..I decide to hook up a 12V 2-amp battery charger into the drill and
see what
happens, unfortunately in reverse polarity. The moment I press the "on"
button on
the drill I see a flash-bang and smoke from the transistor. I thought,
"How am I
going to find a replacement part?" Does anyone know what other
transistor is
compatible with this one? Or, any reverse polarity preventive advice? -
as this
is not my first case.

_I think_ this may be a power transistor. Try using a 2N3055 for a start.

Actually if it's in a drill, it's most likely an N channel power MOSFET.
 
"Chaos Master" <ask_for_the_address@yahoo.com> wrote
Tibur Waltson[Toush@hi.com]

Does anyone know what other transistor is
compatible with this one?

_I think_ this may be a power transistor. Try using a 2N3055 for a start.
BTW, is the OP trolling? No model/transistor markings were given.
I left out the make/model/transistor intentionally, see why. Sorry about
that. Also posted the wrong voltage. This is an 18V unit. Here's the
manufacture:

American Tool Exchange and Chicago Electric Power tools. 1/2" 18V VSR.
These are two identical drills. Here what it looks like
http://tinyurl.com/2tlmu

Reasons for not posting model:

1. The drill is heavily used and labels regarding models were damaged or
removed.
2. The transistor on drill #1 is blown and unreadable. The transistor on
drill #2 is not blown but has no labels (generic version - made in china.)

How it works: Inside the trigger handle contains an IC stamp on a tiny
circuit board with resistors and capacitors. This, I believe, in part,
controls the power transistor and also reverses the polarity briefly to stop
the chuck from further spinning when trigger is release. This circuit board
is not damage, since I swap the power transistors and is working fine. The
question is what other transistors can take it's place? 2N3055 or an N
channel power MOSFET or either?
Tibur
 
"Tibur Waltson" <Toush@hi.com> wrote in message
news:dfda5fbdd357c9011191e4c42e6c57f3@news.bubbanews.com...
"Chaos Master" <ask_for_the_address@yahoo.com> wrote
Tibur Waltson[Toush@hi.com]

Does anyone know what other transistor is
compatible with this one?

_I think_ this may be a power transistor. Try using a 2N3055 for a
start.
BTW, is the OP trolling? No model/transistor markings were given.

I left out the make/model/transistor intentionally, see why. Sorry about
that. Also posted the wrong voltage. This is an 18V unit. Here's the
manufacture:

American Tool Exchange and Chicago Electric Power tools. 1/2" 18V VSR.
These are two identical drills. Here what it looks like
http://tinyurl.com/2tlmu

Reasons for not posting model:

1. The drill is heavily used and labels regarding models were damaged or
removed.
2. The transistor on drill #1 is blown and unreadable. The transistor on
drill #2 is not blown but has no labels (generic version - made in china.)

How it works: Inside the trigger handle contains an IC stamp on a tiny
circuit board with resistors and capacitors. This, I believe, in part,
controls the power transistor and also reverses the polarity briefly to
stop
the chuck from further spinning when trigger is release. This circuit
board
is not damage, since I swap the power transistors and is working fine. The
question is what other transistors can take it's place? 2N3055 or an N
channel power MOSFET or either?
Tibur

A 2N3055 is completely wrong, that's a large TO-3 case NPN transistor. Try a
mosfet, you can't lose by trying, one of the IRF series should work, IRF840,
820, 740, etc.
 

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