tranisitor help

[Imran]

Hello,

I have a home irrigation controller hat has gone faulty on one of the zones,
I have opened it up and have found one of the transistors to be faulty there
is a number on the transistor but it looks like its a part number from the
manufacturer of the irrigation unit rather then the actual part number of
the transistor.

The number written on it is 1401ES or 1401E5 cant make out if its a 5 or an
S but looks like an S to me and sound like it might be an NPN transistor.

The purpose of this transiston from what I can tell from the board is to
turn a solenoid on and off.

The Irrigation unit is made by Holman Distributors.

Any help you can provide would be greatly appreciated.

Thanks
Imran Khan

 

[Robert Baer]

Imran wrote:

Hello,

I have a home irrigation controller hat has gone faulty on one of the zones,
I have opened it up and have found one of the transistors to be faulty there
is a number on the transistor but it looks like its a part number from the
manufacturer of the irrigation unit rather then the actual part number of
the transistor.

The number written on it is 1401ES or 1401E5 cant make out if its a 5 or an
S but looks like an S to me and sound like it might be an NPN transistor.

The purpose of this transiston from what I can tell from the board is to
turn a solenoid on and off.

The Irrigation unit is made by Holman Distributors.

Any help you can provide would be greatly appreciated.

Thanks
Imran Khan


Simple.

Measure the voltage between the collector and the emitter to
determine NPN or PNP; even if it is "shorted" usually the resistance is
high enough to read at least 50mV and thus get polarity.
Then replace with any transistor of same "sex" and similar power
rating; if original has a heatsink or is on a heatsink, then same case.

 

[Walter Harley]

"Imran" <messenger_boy_2005@hotmail.com> wrote in message
news:12eklscsa9ftg2b@corp.supernews.com...

Hello,

I have a home irrigation controller hat has gone faulty on one of the
zones, I have opened it up and have found one of the transistors to be
faulty there is a number on the transistor but it looks like its a part
number from the manufacturer of the irrigation unit rather then the actual
part number of the transistor.

The number written on it is 1401ES or 1401E5 cant make out if its a 5 or
an S but looks like an S to me and sound like it might be an NPN
transistor.

The purpose of this transiston from what I can tell from the board is to
turn a solenoid on and off.

If only one of the zones is bad, you might be able to measure the
corresponding transistor from one of the good zones, to figure out whether
it is indeed an NPN transistor (as opposed to, say, a MOSFET). That will
also tell you whether it's a Darlington or normal transistor; normal
transistor Vbe is around 0.6 to 0.7v, where a Darlington would be twice
that.