Question for the group..

D

Dave

Guest
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first thing I
note about it is that it makes prodigious use of the 2N3904 transistor on
its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather than
the typical OL that the others measure, or that I get from a 2N3904 out of
stock. (Note that this is with the negative or black lead from the DMM on
the emittor and the positive or red on the collector, that I get a .676 VDC
reading on the DMM.)

Anybody have any idea as to what this would indicate about the particular
transistor in question? It's been too may years since I've done this on a
regular basis, and I'm having to clean the cobwebs out of the attice to try
and figure it out. MANY THANKS for any feedback.

Dave
 
"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first thing
I note about it is that it makes prodigious use of the 2N3904 transistor on
its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather than
the typical OL that the others measure, or that I get from a 2N3904 out of
stock. (Note that this is with the negative or black lead from the DMM on
the emittor and the positive or red on the collector, that I get a .676 VDC
reading on the DMM.)

Anybody have any idea as to what this would indicate about the particular
transistor in question? It's been too may years since I've done this on a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

Dave
Click to expand...
Just realized, I am talking about using the DMM in DIODE-TEST function, but
I didn't indicate that.

D
 
On 4/18/13 11:29 AM, Dave wrote:
"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first thing
I note about it is that it makes prodigious use of the 2N3904 transistor on
its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather than
the typical OL that the others measure, or that I get from a 2N3904 out of
stock. (Note that this is with the negative or black lead from the DMM on
the emittor and the positive or red on the collector, that I get a .676 VDC
reading on the DMM.)

Anybody have any idea as to what this would indicate about the particular
transistor in question? It's been too may years since I've done this on a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

Dave



Just realized, I am talking about using the DMM in DIODE-TEST function, but
I didn't indicate that.

D


If there is no other voltage across the circuit, this sounds like a
Click to expand...
defective transistor with a short in it. Measure it with the ohm
setting. In theory, with no voltage, VCE should be infinity ohms.

With a .676v drop, it sounds like it is acting like a diode, rather than
a transistor.
 
"Daniel Pitts" <newsgroup.nospam@virtualinfinity.net> wrote in message
news:KhXbt.60885$iT2.58548@newsfe01.iad...
On 4/18/13 11:29 AM, Dave wrote:

"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing
I note about it is that it makes prodigious use of the 2N3904 transistor
on
its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than
the typical OL that the others measure, or that I get from a 2N3904 out
of
stock. (Note that this is with the negative or black lead from the DMM
on
the emittor and the positive or red on the collector, that I get a .676
VDC
reading on the DMM.)

Anybody have any idea as to what this would indicate about the
particular
transistor in question? It's been too may years since I've done this on
a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

Dave



Just realized, I am talking about using the DMM in DIODE-TEST function,
but
I didn't indicate that.

D


If there is no other voltage across the circuit, this sounds like a
defective transistor with a short in it. Measure it with the ohm setting.
In theory, with no voltage, VCE should be infinity ohms.

With a .676v drop, it sounds like it is acting like a diode, rather than a
transistor.
Click to expand...
AAahhh. Thank you, that is what it sounds like I guess. Over half of the
2N3904s on the main control board are exhibiting this particular
characteristic, which makes me wonder what other demons lurk within. One of
them even shows a 1.6 VDC characteristic across the emittor/collector.
Wondering now if all the ICs on the board are likely trashed, but I guess
I'll see to that after I get the transisors replaced.

Thanks again. I'll check them with the OHMS setting.

Dave
 
On Thu, 18 Apr 2013 13:27:18 -0500, "Dave" <db5151@hotmail.com> wrote:

I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first thing I
note about it is that it makes prodigious use of the 2N3904 transistor on
its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather than
the typical OL that the others measure, or that I get from a 2N3904 out of
stock. (Note that this is with the negative or black lead from the DMM on
the emittor and the positive or red on the collector, that I get a .676 VDC
reading on the DMM.)

Anybody have any idea as to what this would indicate about the particular
transistor in question? It's been too may years since I've done this on a
regular basis, and I'm having to clean the cobwebs out of the attice to try
and figure it out. MANY THANKS for any feedback.
Click to expand...
If it's a "diode-connected" setup (base and collector connected) then
you will get that typical diode drop voltage in the usual diode-test
mode on the multimeter. That configuration is used as a temperature
sensor, which might reasonably show up in a charger control circuit.
 
On 4/18/13 12:13 PM, Dave wrote:
"Daniel Pitts" <newsgroup.nospam@virtualinfinity.net> wrote in message
news:KhXbt.60885$iT2.58548@newsfe01.iad...
On 4/18/13 11:29 AM, Dave wrote:

"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing
I note about it is that it makes prodigious use of the 2N3904 transistor
on
its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than
the typical OL that the others measure, or that I get from a 2N3904 out
of
stock. (Note that this is with the negative or black lead from the DMM
on
the emittor and the positive or red on the collector, that I get a .676
VDC
reading on the DMM.)

Anybody have any idea as to what this would indicate about the
particular
transistor in question? It's been too may years since I've done this on
a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

Dave



Just realized, I am talking about using the DMM in DIODE-TEST function,
but
I didn't indicate that.

D


If there is no other voltage across the circuit, this sounds like a
defective transistor with a short in it. Measure it with the ohm setting.
In theory, with no voltage, VCE should be infinity ohms.

With a .676v drop, it sounds like it is acting like a diode, rather than a
transistor.

AAahhh. Thank you, that is what it sounds like I guess. Over half of the
2N3904s on the main control board are exhibiting this particular
characteristic, which makes me wonder what other demons lurk within. One of
them even shows a 1.6 VDC characteristic across the emittor/collector.
Wondering now if all the ICs on the board are likely trashed, but I guess
I'll see to that after I get the transisors replaced.

Thanks again. I'll check them with the OHMS setting.

Dave


Note that your DMM is applying voltage to the circuit, so it could be
Click to expand...
that if you aren't isolating these components, the reading is actually
expected for the circuit.

Ohms setting likely applies less voltage (though I'm not certain about
that), so it may be "more accurate" indicator of a problem. If multiple
transistors are showing this "short", then I suspect its a problem with
the measurement rather than the device.

Now, here is the disclaimer. I'm very amateur, so take all my advice
with a hunk of salt.
 
"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first thing
I note about it is that it makes prodigious use of the 2N3904 transistor
on its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than the typical OL that the others measure, or that I get from a 2N3904
out of stock. (Note that this is with the negative or black lead from the
DMM on the emittor and the positive or red on the collector, that I get a
.676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the particular
transistor in question? It's been too may years since I've done this on a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.
Click to expand...
You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce a
voltage for the "fully automatic battery charger" to sense. A totally dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case I
encounter a dead flat battery.
 
Dave wrote:
"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...

I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first thing
I note about it is that it makes prodigious use of the 2N3904 transistor on
its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather than
the typical OL that the others measure, or that I get from a 2N3904 out of
stock. (Note that this is with the negative or black lead from the DMM on
the emittor and the positive or red on the collector, that I get a .676 VDC
reading on the DMM.)

Anybody have any idea as to what this would indicate about the particular
transistor in question? It's been too may years since I've done this on a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

Dave




Just realized, I am talking about using the DMM in DIODE-TEST function, but
I didn't indicate that.

D


You need to detach it from the circuit for a proper test. Just unsolder
Click to expand...
a couple of legs.. You could have a diode in the circuit that is giving
you a false reading.

Jamie
 
"Ian Field" <gangprobing.alien@ntlworld.com> wrote in message
news:K%Zbt.26871$9T.9571@fx22.fr7...
"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing I note about it is that it makes prodigious use of the 2N3904
transistor on its main control board. And one of these (2N3904) has an
odd characteristic- it measures .676 VDC from emittor to collector,
rather than the typical OL that the others measure, or that I get from a
2N3904 out of stock. (Note that this is with the negative or black lead
from the DMM on the emittor and the positive or red on the collector,
that I get a .676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the particular
transistor in question? It's been too may years since I've done this on
a regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce a
voltage for the "fully automatic battery charger" to sense. A totally dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case I
encounter a dead flat battery.
Click to expand...
Hmm. That's interesting. How do you make use of the transformer?
Thanks...

D
 
"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:lRZbt.544910$kp4.259294@newsfe09.iad...
Dave wrote:
"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...

I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing I note about it is that it makes prodigious use of the 2N3904
transistor on its main control board. And one of these (2N3904) has an
odd characteristic- it measures .676 VDC from emittor to collector,
rather than the typical OL that the others measure, or that I get from a
2N3904 out of stock. (Note that this is with the negative or black lead
from the DMM on the emittor and the positive or red on the collector,
that I get a .676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the particular
transistor in question? It's been too may years since I've done this on
a regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

Dave




Just realized, I am talking about using the DMM in DIODE-TEST function,
but I didn't indicate that.

D


You need to detach it from the circuit for a proper test. Just unsolder
a couple of legs.. You could have a diode in the circuit that is giving
you a false reading.

Jamie
Click to expand...
I pulled it out and got the same reading, so replaced that transistor. Had
enough trouble doing this I decided to leave the others alone, as they
didn't seem as troubled. Figured I would wait and see how it functioned
when I hooked it back up to an actual battery... If need be I'll tackle it
again.

Thanks to all for the input.


Dave
 
"Dave" <db5151@hotmail.com> wrote in message
news:1f2dncDNx5E7K-3MnZ2dnUVZ_qadnZ2d@posted.internetamerica...
"Ian Field" <gangprobing.alien@ntlworld.com> wrote in message
news:K%Zbt.26871$9T.9571@fx22.fr7...


"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing I note about it is that it makes prodigious use of the 2N3904
transistor on its main control board. And one of these (2N3904) has an
odd characteristic- it measures .676 VDC from emittor to collector,
rather than the typical OL that the others measure, or that I get from a
2N3904 out of stock. (Note that this is with the negative or black lead
from the DMM on the emittor and the positive or red on the collector,
that I get a .676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the
particular transistor in question? It's been too may years since I've
done this on a regular basis, and I'm having to clean the cobwebs out of
the attice to try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce
a voltage for the "fully automatic battery charger" to sense. A totally
dead flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case I
encounter a dead flat battery.

Hmm. That's interesting. How do you make use of the transformer?
Thanks...
Click to expand...
Its in a battery charger - you charge the battery with it.

Most old style chargers have the transformer deliberately wound for poor
regulation - that is a sulphated battery that draws almost no charge current
will get well over the nominal 14.4V as (and if) the battery recovers and
starts to draw charge current, the transformer output voltage drops.

Many automatic chargers have a pulse mode for recovering neglected
batteries, but they still won't start if there isn't enough residual
terminal voltage to activate the polarity sensing.
 
On Thu, 18 Apr 2013 22:58:09 +0100, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first thing
I note about it is that it makes prodigious use of the 2N3904 transistor
on its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than the typical OL that the others measure, or that I get from a 2N3904
out of stock. (Note that this is with the negative or black lead from the
DMM on the emittor and the positive or red on the collector, that I get a
.676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the particular
transistor in question? It's been too may years since I've done this on a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce a
voltage for the "fully automatic battery charger" to sense. A totally dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case I
encounter a dead flat battery.
Click to expand...
---
Interesting...

I wasn't aware you could use the AC output from an old iron-cored
transformer to get a dead flat battery started.

How does that work, exactly?

--
JF
 
On Sun, 21 Apr 2013 08:07:50 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Thu, 18 Apr 2013 22:58:09 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first thing
I note about it is that it makes prodigious use of the 2N3904 transistor
on its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than the typical OL that the others measure, or that I get from a 2N3904
out of stock. (Note that this is with the negative or black lead from the
DMM on the emittor and the positive or red on the collector, that I get a
.676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the particular
transistor in question? It's been too may years since I've done this on a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce a
voltage for the "fully automatic battery charger" to sense. A totally dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case I
encounter a dead flat battery.

---
Interesting...

I wasn't aware you could use the AC output from an old iron-cored
transformer to get a dead flat battery started.

How does that work, exactly?
Click to expand...
"Old iron-cored" smoke ?:-}

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
"John Fields" <jfields@austininstruments.com> wrote in message
news:fvo7n8pr4nmc93g160oc68bvh8rkrfquh4@4ax.com...
On Thu, 18 Apr 2013 22:58:09 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing
I note about it is that it makes prodigious use of the 2N3904 transistor
on its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than the typical OL that the others measure, or that I get from a 2N3904
out of stock. (Note that this is with the negative or black lead from
the
DMM on the emittor and the positive or red on the collector, that I get
a
.676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the
particular
transistor in question? It's been too may years since I've done this on
a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce a
voltage for the "fully automatic battery charger" to sense. A totally dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case I
encounter a dead flat battery.

---
Interesting...

I wasn't aware you could use the AC output from an old iron-cored
transformer to get a dead flat battery started.

How does that work, exactly?
Click to expand...

Well as long as the best you can do is pick on the occasional typo, I've
little to worry about.
 
On Sun, 21 Apr 2013 17:39:30 +0100, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:fvo7n8pr4nmc93g160oc68bvh8rkrfquh4@4ax.com...
On Thu, 18 Apr 2013 22:58:09 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing
I note about it is that it makes prodigious use of the 2N3904 transistor
on its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than the typical OL that the others measure, or that I get from a 2N3904
out of stock. (Note that this is with the negative or black lead from
the
DMM on the emittor and the positive or red on the collector, that I get
a
.676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the
particular
transistor in question? It's been too may years since I've done this on
a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce a
voltage for the "fully automatic battery charger" to sense. A totally dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case I
encounter a dead flat battery.

---
Interesting...

I wasn't aware you could use the AC output from an old iron-cored
transformer to get a dead flat battery started.

How does that work, exactly?


Well as long as the best you can do is pick on the occasional typo, I've
little to worry about.
Click to expand...
---
You wrote: "I keep an old iron cored transformer to get things started
just in case I encounter a dead flat battery."

Where's the typo???

--
JF
 
On Sun, 21 Apr 2013 15:06:56 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Sun, 21 Apr 2013 17:39:30 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"John Fields" <jfields@austininstruments.com> wrote in message
news:fvo7n8pr4nmc93g160oc68bvh8rkrfquh4@4ax.com...
On Thu, 18 Apr 2013 22:58:09 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing
I note about it is that it makes prodigious use of the 2N3904 transistor
on its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than the typical OL that the others measure, or that I get from a 2N3904
out of stock. (Note that this is with the negative or black lead from
the
DMM on the emittor and the positive or red on the collector, that I get
a
.676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the
particular
transistor in question? It's been too may years since I've done this on
a
regular basis, and I'm having to clean the cobwebs out of the attice to
try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce a
voltage for the "fully automatic battery charger" to sense. A totally dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case I
encounter a dead flat battery.

---
Interesting...

I wasn't aware you could use the AC output from an old iron-cored
transformer to get a dead flat battery started.

How does that work, exactly?


Well as long as the best you can do is pick on the occasional typo, I've
little to worry about.

---
You wrote: "I keep an old iron cored transformer to get things started
just in case I encounter a dead flat battery."

Where's the typo???
Click to expand...
Probably the "dead flat battery" was caused by the power steering pump
because the wheels weren't parked straight ahead ;-)

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
"John Fields" <jfields@austininstruments.com> wrote in message
news:arg8n8l0oie8hgors1et4ps0bde2faiqfr@4ax.com...
On Sun, 21 Apr 2013 17:39:30 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"John Fields" <jfields@austininstruments.com> wrote in message
news:fvo7n8pr4nmc93g160oc68bvh8rkrfquh4@4ax.com...
On Thu, 18 Apr 2013 22:58:09 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing
I note about it is that it makes prodigious use of the 2N3904
transistor
on its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than the typical OL that the others measure, or that I get from a
2N3904
out of stock. (Note that this is with the negative or black lead from
the
DMM on the emittor and the positive or red on the collector, that I
get
a
.676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the
particular
transistor in question? It's been too may years since I've done this
on
a
regular basis, and I'm having to clean the cobwebs out of the attice
to
try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce
a
voltage for the "fully automatic battery charger" to sense. A totally
dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case
I
encounter a dead flat battery.

---
Interesting...

I wasn't aware you could use the AC output from an old iron-cored
transformer to get a dead flat battery started.

How does that work, exactly?


Well as long as the best you can do is pick on the occasional typo, I've
little to worry about.

---
You wrote: "I keep an old iron cored transformer to get things started
just in case I encounter a dead flat battery."

Where's the typo???
Click to expand...
Ah - I see now. You're too thick to see where I was going with that.
 
On Sun, 21 Apr 2013 21:23:54 +0100, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:arg8n8l0oie8hgors1et4ps0bde2faiqfr@4ax.com...
On Sun, 21 Apr 2013 17:39:30 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"John Fields" <jfields@austininstruments.com> wrote in message
news:fvo7n8pr4nmc93g160oc68bvh8rkrfquh4@4ax.com...
On Thu, 18 Apr 2013 22:58:09 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing
I note about it is that it makes prodigious use of the 2N3904
transistor
on its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than the typical OL that the others measure, or that I get from a
2N3904
out of stock. (Note that this is with the negative or black lead from
the
DMM on the emittor and the positive or red on the collector, that I
get
a
.676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the
particular
transistor in question? It's been too may years since I've done this
on
a
regular basis, and I'm having to clean the cobwebs out of the attice
to
try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce
a
voltage for the "fully automatic battery charger" to sense. A totally
dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case
I
encounter a dead flat battery.

---
Interesting...

I wasn't aware you could use the AC output from an old iron-cored
transformer to get a dead flat battery started.

How does that work, exactly?


Well as long as the best you can do is pick on the occasional typo, I've
little to worry about.

---
You wrote: "I keep an old iron cored transformer to get things started
just in case I encounter a dead flat battery."

Where's the typo???

Ah - I see now. You're too thick to see where I was going with that.
Click to expand...
---
Then, since you didn't see before and your direction was indefinite,
your blaming others for being unable to read your mind is
disingenuous.

--
JF
 
On Mon, 22 Apr 2013 14:19:00 -0500, John Fields
<jfields@austininstruments.com> wrote:

On Sun, 21 Apr 2013 21:23:54 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"John Fields" <jfields@austininstruments.com> wrote in message
news:arg8n8l0oie8hgors1et4ps0bde2faiqfr@4ax.com...
On Sun, 21 Apr 2013 17:39:30 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"John Fields" <jfields@austininstruments.com> wrote in message
news:fvo7n8pr4nmc93g160oc68bvh8rkrfquh4@4ax.com...
On Thu, 18 Apr 2013 22:58:09 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing
I note about it is that it makes prodigious use of the 2N3904
transistor
on its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector, rather
than the typical OL that the others measure, or that I get from a
2N3904
out of stock. (Note that this is with the negative or black lead from
the
DMM on the emittor and the positive or red on the collector, that I
get
a
.676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the
particular
transistor in question? It's been too may years since I've done this
on
a
regular basis, and I'm having to clean the cobwebs out of the attice
to
try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by the
battery to detect correct polarity - obviously a "load" will not produce
a
voltage for the "fully automatic battery charger" to sense. A totally
dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in case
I
encounter a dead flat battery.

---
Interesting...

I wasn't aware you could use the AC output from an old iron-cored
transformer to get a dead flat battery started.

How does that work, exactly?


Well as long as the best you can do is pick on the occasional typo, I've
little to worry about.

---
You wrote: "I keep an old iron cored transformer to get things started
just in case I encounter a dead flat battery."

Where's the typo???

Ah - I see now. You're too thick to see where I was going with that.

---
Then, since you didn't see before and your direction was indefinite,
your blaming others for being unable to read your mind is
disingenuous.
Click to expand...
Ian is running for cover via Larkinesque-style obfuscation.

Next will come the epithets.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
 
On 4/21/2013 3:23 PM, Ian Field wrote:
"John Fields" <jfields@austininstruments.com> wrote in message
news:arg8n8l0oie8hgors1et4ps0bde2faiqfr@4ax.com...
On Sun, 21 Apr 2013 17:39:30 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"John Fields" <jfields@austininstruments.com> wrote in message
news:fvo7n8pr4nmc93g160oc68bvh8rkrfquh4@4ax.com...
On Thu, 18 Apr 2013 22:58:09 +0100, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Dave" <db5151@hotmail.com> wrote in message
news:CKSdnQkD39KYpu3MnZ2dnUVZ_hmdnZ2d@posted.internetamerica...
I have an automatic battery charger which is totally non-functional,
apparently not sensing when it is connected to a load, and the first
thing
I note about it is that it makes prodigious use of the 2N3904
transistor
on its main control board. And one of these (2N3904) has an odd
characteristic- it measures .676 VDC from emittor to collector,
rather
than the typical OL that the others measure, or that I get from a
2N3904
out of stock. (Note that this is with the negative or black lead
from
the
DMM on the emittor and the positive or red on the collector, that
I get
a
.676 VDC reading on the DMM.)

Anybody have any idea as to what this would indicate about the
particular
transistor in question? It's been too may years since I've done
this on
a
regular basis, and I'm having to clean the cobwebs out of the
attice to
try and figure it out. MANY THANKS for any feedback.

You say "not sensing when its connected to to a load" as if the
load was
something other than a battery.

Your "fully automatic battery charger" senses a voltage produced by
the
battery to detect correct polarity - obviously a "load" will not
produce a
voltage for the "fully automatic battery charger" to sense. A
totally dead
flat battery will also not provide a voltage for polarity detection.

I keep an old iron cored transformer to get things started just in
case I
encounter a dead flat battery.

---
Interesting...

I wasn't aware you could use the AC output from an old iron-cored
transformer to get a dead flat battery started.

How does that work, exactly?


Well as long as the best you can do is pick on the occasional typo, I've
little to worry about.

---
You wrote: "I keep an old iron cored transformer to get things started
just in case I encounter a dead flat battery."

Where's the typo???

Ah - I see now. You're too thick to see where I was going with that.
Yes, I'm too thick also.
Click to expand...
What did you mean to say?
Mikek
 
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