Root cause insight into the common BMW blower motor resistor

[Jamie]

Bimmer Owner wrote:

On Mon, 25 Mar 2013 21:42:16 -0700, jim beam wrote:


or google for this guy:
"ESI 695 80 Amps DC/AC Low Current Probe"


This seems to only be $107 but it doesn't say whether it works
with the Fluke 75 or not.
http://www.amazon.com/ESI-695-Amps-Current-Probe/dp/B000FN4IUK

Actually that looks good and should work just fine.

That type of probe is self contained, meaning it does
not depend on the DMM input impedance for proper match.

BUt 80 Amps is kind of small I think, I have a AC/DC clamp
that does 800 amps, but to do low current readings of less than 1
amp becomes a problem with AC. DC I can zero it.

Jamie

 

[Michael A. Terrell]

Bimmer Owner wrote:

On Tue, 26 Mar 2013 14:09:11 -0400, Michael A. Terrell wrote:

I think the IC is a dual, high side motor driver IC

It might be, but this Russian site intimates it's a temperature
compensated voltage controller.
http://tinyurl.com/crg2sms
http://kazus.ru/schematics/electrical-engineering/search/go/?text=%D0%C5%C3%D3%CB%DF%D2%CE%D0%20ELMOS%2010901D&nohistory=1&h=1
http://monitor.espec.ws/section27/topic189041.html
http://item.taobao.com/item.htm?id=13918440884

Be careful with so called information from those types of sites. Most
of their information is badly translated, or just plain wrong. Tabao.com
is a prime example of crap information. I have never found correct
information there. Most is from chinese Ebay sellers who make things up
about items they sell. They have no idea what it is, just that they can
sell it on Ebay or Tabao.com.

Translation below:
REGULATOR ELMOS 10901D
Found: 100 Showing: 1 - 10
Car Voltage Regulator
Category: Car
Source: Radioland country Electronics
Temperature controller cabin air KAMAZ
Category: Car
Source: Plans radiokonstruktsy
Simple Temperature compensated voltage regulator. Controller together with thyristor-transistor electronic ignition unit with a long spark, ensuring the rapid start-ups at various operating conditions, allowed to increase battery life of up to nine years.
Category: Car
Source: For the life of a soldering iron ...
Regulator for automotive windshield
Category: Car
Source: MASTER KIT
The controller measures the wiper-this control is designed to use regular mode switch blades and is contactless.
Category: Car
Source: For the life of a soldering iron ...
Temperature compensated voltage regulator device in some ways superior designs. The controller can be used as a universal device is suitable not only for mounting on any car, but everywhere, where the generator rotor speed is variable (eg, wind power). Choose the appropriate control elements, it can be easily adapted to work with any voltage (up to 400V) and excitation current (tens of amperes).
Category: Car
Source: For the life of a soldering iron ...
Voltage regulator 2012.3702, 22.3702, 221.3702
Category: Car
Source: For the life of a soldering iron ...
Voltage regulator 201.3702
Category: Car
Source: For the life of a soldering iron ...
Voltage Regulator 13.3702
Category: Car
Source: For the life of a soldering iron ...
Voltage regulator RR132A, 1112.3702
Category: Car
Source: For the life of a soldering iron ...

--

Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

Sometimes Friday is just the fifth Monday of the week.

 

[Jamie]

Bimmer Owner wrote:

On Tue, 26 Mar 2013 04:58:48 +0000, Bimmer Owner wrote:


This seems to only be $107 but it doesn't say whether it works
with the Fluke 75 or not.
http://www.amazon.com/ESI-695-Amps-Current-Probe/dp/B000FN4IUK


For the same price, it looks like we can get a separate unit:
http://www.westsidewholesale.com/gifts-more/tools-more-clearance/fluke/fluke-t5-600.html

Fluke T5-600, SKU: 133038, $109.95

It only does AC amps.. If you look closer, there is no statement
about DC current.

You want one that does both and they normally have a Hall detector in
the jaws.

Don't waste your money..

Jamie

 

[Jamie]

jim beam wrote:

On 03/26/2013 05:58 AM, Scott Dorsey wrote:

In article <kiqq93$fdc$3@dont-email.me>, jim beam <me@privacy.net
wrote:

On 03/25/2013 05:57 PM, Jamie wrote:

jim beam wrote:

Another way to do this, is to have an inductor on board with the
speed control circuit. You would PWM that inductor in series to a
filter
cap
on the output which will then give you a clean variable DC. THe
inductor
will be doing all variable voltages.


ok, as i understand it, and as i said to scott earlier, this is a
problem because it mungs low speed motor start and low speed torque.


Not really, it's feeding the motor with variable DC from that integrator
stage.


i understand that - and variable voltage is the problem. the secondary
[bordering on primary in some applications] advantage of pwm is low
speed start and torque. if a motor starts at low dc voltage, not only
is the start speed inconsistent, it has little torque. pwm can start a
motor slower and at much higher torque. it's a big deal.


A properly working blower motor does not need extra torque to start at

low RPMs.

Torque is only needed when RPMs increase and mass air flow is
increased, thereby, putting a strain on the motor. Basic resistor
systems will vary in speed if air pressure isn't constant, and in
most cases it isn't..

When there is no air flow or the flow has been restricted somehow,
there is little to no torque demand, other than mechanical of the blower
blades and those should turn easy, sine bearings and balance permits this.

PWM is just a cheap way of speed control, it does not mean it's
better, in fact in some ways it's not, due to over head in noise..

A linear control with feed back will provide the needed torque but
they do tend to run hot when throttled back, because of the resistance
being present between the 12V and the motor terminals. THis is where
PWM comes in a winner but then you need the added cost of noise
reduction engineering.

I can only assume the linear module at least uses a feed back to
maintain output voltage, if it is so cheap that it does not even
do that, then maybe they are trying to emulate a real resistor or
they are just shitty engineers or tightwads.

Jamie

 

[jim beam]

On 03/26/2013 05:16 PM, Jamie wrote:

jim beam wrote:

On 03/26/2013 05:58 AM, Scott Dorsey wrote:

In article <kiqq93$fdc$3@dont-email.me>, jim beam <me@privacy.net
wrote:

On 03/25/2013 05:57 PM, Jamie wrote:

jim beam wrote:

Another way to do this, is to have an inductor on board with the
speed control circuit. You would PWM that inductor in series to a
filter
cap
on the output which will then give you a clean variable DC. THe
inductor
will be doing all variable voltages.


ok, as i understand it, and as i said to scott earlier, this is a
problem because it mungs low speed motor start and low speed torque.


Not really, it's feeding the motor with variable DC from that integrator
stage.


i understand that - and variable voltage is the problem. the
secondary [bordering on primary in some applications] advantage of pwm
is low speed start and torque. if a motor starts at low dc voltage,
not only is the start speed inconsistent, it has little torque. pwm
can start a motor slower and at much higher torque. it's a big deal.


A properly working blower motor does not need extra torque to start at
low RPMs.

Torque is only needed when RPMs increase and mass air flow is
increased, thereby, putting a strain on the motor.

you're right, except that there are more variables. very cold days,
very windy days, blown snow powder, leaves, all kinds of things can mess
with the motor starting at a low speed.

Basic resistor
systems will vary in speed if air pressure isn't constant, and in
most cases it isn't..

When there is no air flow or the flow has been restricted somehow,
there is little to no torque demand, other than mechanical of the blower
blades and those should turn easy, sine bearings and balance permits this.

PWM is just a cheap way of speed control, it does not mean it's
better, in fact in some ways it's not, due to over head in noise..

from what i can see, the /only/ drawback is noise. power efficiency,
controllability, speed consistency, and yes, sometimes price, all are
wins for pwm.

A linear control with feed back will provide the needed torque but
they do tend to run hot when throttled back, because of the resistance
being present between the 12V and the motor terminals. THis is where
PWM comes in a winner but then you need the added cost of noise
reduction engineering.

I can only assume the linear module at least uses a feed back to
maintain output voltage, if it is so cheap that it does not even
do that, then maybe they are trying to emulate a real resistor or
they are just shitty engineers or tightwads.

well, they're clearly failing at something if they're trying to provide
an engineering solution. if however they're providing a financial
solution with a per-determined failure rate, then they're right on target.


--
fact check required

 

[Jamie]

trader4@optonline.net wrote:

On Mar 26, 3:31 pm, Bimmer Owner <dontask...@mymail.com> wrote:

On Tue, 26 Mar 2013 14:56:21 -0400, tm wrote:

Any evidence it was checked with a scope?

Yes.

This quote below is verbatim from this location:
http://www.bimmerfest.com/forums/showpost.php?p=6536514&postcount=131

Hi, After soldering the lost/refound component,
remaking the joints of the 2 mosfet and testing the FSU alone with an
oscilloscope, here are my observations:

- the FSU works again

- there is no PWM ,



You said you tested the FSU alone. If so, how can you
say there is no PWM signal between the car and FSU?


the gates signals are continuous voltage only , this is the reason
why it heat so much its aluminium box... In fact there is no point on
the board where square signals are present. Can somebody check its own
FSU if it's the same ?

- the 2 bridges are in fact 2 resistors 10 milliohm used to balance the currents between the 2 MOSFET and balance the power also. The mesure of the DC voltage on those resistors can be used to evaluate the current of the blower and its worn state.


Say what? 10 milliohms is .01 ohms. How could that
possibly balance the power to a motor in a 40 amp circuit?

Resistors are used in the emitter path when combining two or more
to the same circuit. This is needed to insure both transistors
share in the load when it comes to biasing... Otherwise, you'll
get one that favors beta and the other will sit back and snooze.
Call it a ballast R if you wish.. These R values are generally
low.

Jamie

 

[Jamie]

Bimmer Owner wrote:

On Tue, 26 Mar 2013 19:41:47 +0000, Bimmer Owner wrote:


Can someone circle the resistors for me? I would think they would be fairly
decent wattage so they would be very easy to see, but I don't see any
resistors.


I 'think' (but I'm not sure) that these are the resistors in series:
http://www5.picturepush.com/photo/a/12516343/img/12516343.jpg

Yup, and I see the legs of the transistors (two). So those R's are in

line with the emitters where they joint.

Most likely thermo stress cracks due to the potting restraint.

Jamie

 

[Jamie]

trader4@optonline.net wrote:

On Mar 26, 4:09 pm, Bimmer Owner <dontask...@mymail.com> wrote:

On Tue, 26 Mar 2013 19:41:47 +0000, Bimmer Owner wrote:

Can someone circle the resistors for me? I would think they would be fairly
decent wattage so they would be very easy to see, but I don't see any
resistors.

I 'think' (but I'm not sure) that these are the resistors in series:
http://www5.picturepush.com/photo/a/12516343/img/12516343.jpg


If they are resistors, I've never seen any that look like that.
Also, given that you want to thermally bond any components
that generate major heat, why are they not heat sinked?
With any power design I've seen, the key components, eg
the transistors are directly bonded to the heat sink.

THey make power resistors in T0-220 style cases, for heat sink mounting
however, I doubt those are that.

Jamie

 

[jim beam]

On 03/26/2013 10:41 AM, Michael A. Terrell wrote:

jim beam wrote:

if it's just a two-layer board, maybe. assuming you get the specs on
the chips of course. but you'll need more than two units and a whole
lot of patience trying to reverse the schematic if it's 4 or more
layers. and you still don't achieve anything more than having a broken
light bulb in your hand.

what you need to do is get the operational capacities of the /working/
unit, and work with those. that the unit is a black box is completely
irrelevant.


Yawn. I worked with 16 layer boards at a factory troubleshooting
defective, new boards that cost over $8,000 to stuff.

fantastic. could you condescend to help these guys wit their project
then? or are you just here to whang your donger around?

The internal
routing of a simple low frequency board is irrelevant for drawing a
schematic. You can X-ray a board or mill it one layer at a time if you
want to duplicate the routing. All you need to do for bais reverse
engineering is to trace each with an ohm meter by probing every pad and
termination to identify the signal path and draw a schematic from your
notes. I've done this with four layer boards for 30+ years.

then you're a complete genius because other people find it hard/impossible.

"Specs on
the chips" makes things easier but knowing who made it, and how it's
connected will tell you if it is a custom part or just house numbered.

yeah, a schematic doesn't exactly mean much if you don't even know what
the components actually are. [see above]

There are industrial solvents to remove any potting compound, but
they aren't cheap or easy to buy. Failure analysis is a specialty in
electronics manufacturing. It is expensive but gives you the answers
you need so you can design out the problems.

expensive? you're not kidding. and failure analysis is a whole lot
easier if you know what you're looking at in the first place.

A jig to hold the module in a CNC machine would allow you to cut
accurate holes down to the right points to see if the IC was bad,
without unpotting a failed unit.

yeah, if you know precisely where you're drilling, in three dimensions.
and you have dil/soic [etc] type chips. anything bga or similar, and
you're sol.

and you're not doing that with a black box and getting meaningful data
out of it.

Then a test fixture with 'Pogo Pins'
would allow you to see what was bad. If there were enough bad units, it
would be worth designing and programming a computerized fixture.

ok, but you're missing one simple thing - this is a bunch of guys with a
dremel and a dental pick. money/time are limiting factors, even if
there were logic to reverse engineering, which i don't think there is in
this case.


--
fact check required

 

[jim beam]

On 03/26/2013 11:46 AM, Nate Nagel wrote:

On 03/26/2013 12:35 PM, tm wrote:

"Bimmer Owner" <dontaskfor@mymail.com> wrote in message
news:kisfan$ott$4@news.albasani.net...
On Tue, 26 Mar 2013 08:56:22 -0400, Scott Dorsey wrote:

one person figuring the failure mode out might save a
lot of people that grief.

But mostly it's just intellectual curiosity.

Exactly!


I don't even own a BMW. After this thread, I don't think I ever will.

Like I said before, don't drive one then. It's kind of like going on a
date with that unbelievably attractive female type who is also smart,
witty, fun to be around, actually seems to like you, and oh by the way
is completely mentally unhinged.

no, what you're experiencing is her "disappointment" at discovering that
you are an anosognosic retard.

Suddenly you find yourself putting up with all sorts of stuff that you
wouldn't, otherwise... (now that said, touch wood, current ride has
exhibited none of the known issues... which reminds me, I need to call
and schedule the battery cable recall @ the stealership)

nate

--
fact check required

 

[jim beam]

On 03/26/2013 07:16 PM, Jamie wrote:

jim beam wrote:

On 03/26/2013 05:16 PM, Jamie wrote:

jim beam wrote:

On 03/26/2013 05:58 AM, Scott Dorsey wrote:

In article <kiqq93$fdc$3@dont-email.me>, jim beam <me@privacy.net
wrote:

On 03/25/2013 05:57 PM, Jamie wrote:

jim beam wrote:

Another way to do this, is to have an inductor on board with the
speed control circuit. You would PWM that inductor in series to a
filter
cap
on the output which will then give you a clean variable DC. THe
inductor
will be doing all variable voltages.



ok, as i understand it, and as i said to scott earlier, this is a
problem because it mungs low speed motor start and low speed torque.



Not really, it's feeding the motor with variable DC from that
integrator
stage.



i understand that - and variable voltage is the problem. the
secondary [bordering on primary in some applications] advantage of pwm
is low speed start and torque. if a motor starts at low dc voltage,
not only is the start speed inconsistent, it has little torque. pwm
can start a motor slower and at much higher torque. it's a big deal.


A properly working blower motor does not need extra torque to start at
low RPMs.

Torque is only needed when RPMs increase and mass air flow is
increased, thereby, putting a strain on the motor.


you're right, except that there are more variables. very cold days,
very windy days, blown snow powder, leaves, all kinds of things can
mess with the motor starting at a low speed.


Basic resistor
systems will vary in speed if air pressure isn't constant, and in
most cases it isn't..

When there is no air flow or the flow has been restricted somehow,
there is little to no torque demand, other than mechanical of the blower
blades and those should turn easy, sine bearings and balance permits
this.

PWM is just a cheap way of speed control, it does not mean it's
better, in fact in some ways it's not, due to over head in noise..


from what i can see, the /only/ drawback is noise. power efficiency,
controllability, speed consistency, and yes, sometimes price, all are
wins for pwm.



A linear control with feed back will provide the needed torque but
they do tend to run hot when throttled back, because of the resistance
being present between the 12V and the motor terminals. THis is where
PWM comes in a winner but then you need the added cost of noise
reduction engineering.

I can only assume the linear module at least uses a feed back to
maintain output voltage, if it is so cheap that it does not even
do that, then maybe they are trying to emulate a real resistor or
they are just shitty engineers or tightwads.


well, they're clearly failing at something if they're trying to
provide an engineering solution. if however they're providing a
financial solution with a per-determined failure rate, then they're
right on target.


If that being the case, I guess we now know why the module keeps burning
out

But there is factor that maybe you have forgotten or didn't know, and
that is, the resistance of the DC motor. stall torque can be limited to
what the DC R value is,

didn't know.

in otherwords, this value forms a voltage
divider and thus low voltage at stall current could seem like no voltage
and not turn.

which would be another factor in favor of pwm...

DC PM/SHUNT motors attempt to compensate when load is dragging it
down in speed, that also includes a slow start. So as long as the speed
control can maintain a low voltage set point even when the motor is
calling for high amps - the motor R, it'll still start. However, there
is another factor, the speed control may not be performing armature feed
back and simply supplying current only..

that would be my guess.

If this is the case, then the
motor will stall at low speed demands in conditions that make it hard
for the motor to start.

I've also seen them allow the motor to run in torque mode to adjust
for air density. It'll simply self adjust naturally, and in those cases
you do not want armature feed back but torque feed back. Of course,
this will cause heating of the module when torque demand is low..

i guess that's another part of what we're looking at here.

thanks for the feedback!


--
fact check required

 

[Jamie]

jim beam wrote:

On 03/26/2013 05:16 PM, Jamie wrote:

jim beam wrote:

On 03/26/2013 05:58 AM, Scott Dorsey wrote:

In article <kiqq93$fdc$3@dont-email.me>, jim beam <me@privacy.net
wrote:

On 03/25/2013 05:57 PM, Jamie wrote:

jim beam wrote:

Another way to do this, is to have an inductor on board with the
speed control circuit. You would PWM that inductor in series to a
filter
cap
on the output which will then give you a clean variable DC. THe
inductor
will be doing all variable voltages.



ok, as i understand it, and as i said to scott earlier, this is a
problem because it mungs low speed motor start and low speed torque.



Not really, it's feeding the motor with variable DC from that
integrator
stage.



i understand that - and variable voltage is the problem. the
secondary [bordering on primary in some applications] advantage of pwm
is low speed start and torque. if a motor starts at low dc voltage,
not only is the start speed inconsistent, it has little torque. pwm
can start a motor slower and at much higher torque. it's a big deal.


A properly working blower motor does not need extra torque to start at
low RPMs.

Torque is only needed when RPMs increase and mass air flow is
increased, thereby, putting a strain on the motor.


you're right, except that there are more variables. very cold days,
very windy days, blown snow powder, leaves, all kinds of things can mess
with the motor starting at a low speed.


Basic resistor
systems will vary in speed if air pressure isn't constant, and in
most cases it isn't..

When there is no air flow or the flow has been restricted somehow,
there is little to no torque demand, other than mechanical of the blower
blades and those should turn easy, sine bearings and balance permits
this.

PWM is just a cheap way of speed control, it does not mean it's
better, in fact in some ways it's not, due to over head in noise..


from what i can see, the /only/ drawback is noise. power efficiency,
controllability, speed consistency, and yes, sometimes price, all are
wins for pwm.



A linear control with feed back will provide the needed torque but
they do tend to run hot when throttled back, because of the resistance
being present between the 12V and the motor terminals. THis is where
PWM comes in a winner but then you need the added cost of noise
reduction engineering.

I can only assume the linear module at least uses a feed back to
maintain output voltage, if it is so cheap that it does not even
do that, then maybe they are trying to emulate a real resistor or
they are just shitty engineers or tightwads.


well, they're clearly failing at something if they're trying to provide
an engineering solution. if however they're providing a financial
solution with a per-determined failure rate, then they're right on target.


If that being the case, I guess we now know why the module keeps burning

out

But there is factor that maybe you have forgotten or didn't know, and
that is, the resistance of the DC motor. stall torque can be limited to
what the DC R value is, in otherwords, this value forms a voltage
divider and thus low voltage at stall current could seem like no voltage
and not turn.

DC PM/SHUNT motors attempt to compensate when load is dragging it
down in speed, that also includes a slow start. So as long as the speed
control can maintain a low voltage set point even when the motor is
calling for high amps - the motor R, it'll still start. However, there
is another factor, the speed control may not be performing armature feed
back and simply supplying current only.. If this is the case, then the
motor will stall at low speed demands in conditions that make it hard
for the motor to start.

I've also seen them allow the motor to run in torque mode to adjust
for air density. It'll simply self adjust naturally, and in those cases
you do not want armature feed back but torque feed back. Of course,
this will cause heating of the module when torque demand is low..

Jamie

 

[Michael A. Terrell]

jim beam wrote:

On 03/26/2013 10:41 AM, Michael A. Terrell wrote:

jim beam wrote:

if it's just a two-layer board, maybe. assuming you get the specs on
the chips of course. but you'll need more than two units and a whole
lot of patience trying to reverse the schematic if it's 4 or more
layers. and you still don't achieve anything more than having a broken
light bulb in your hand.

what you need to do is get the operational capacities of the /working/
unit, and work with those. that the unit is a black box is completely
irrelevant.


Yawn. I worked with 16 layer boards at a factory troubleshooting
defective, new boards that cost over $8,000 to stuff.

fantastic. could you condescend to help these guys wit their project
then? or are you just here to whang your donger around?

No, I'm not like you. I have worked in Electronics for 52 years. I
could draw the schematics, but I would need a handful of bad modules and
the time to do it right. Just like the kU band microwave audio, video,
and data terminal hardware I worked on that's in orbit aboard the ISS.
It takes hands on effort to reverse engineer a design.


Bomarc has reverse engineered a lot of automotive modules:

<http://www.bomarc.org/basement/viewtopic.php?f=1&t=6&sid=8ee707756ef37b24ff5aa633f1b4548a>

The one you want might be on their lists.


--

Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

Sometimes Friday is just the fifth Monday of the week.

 

[Vic Smith]

On Tue, 26 Mar 2013 18:02:38 -0700, jim beam <me@privacy.net> wrote:

ok, but you're missing one simple thing - this is a bunch of guys with a
dremel and a dental pick. money/time are limiting factors, even if
there were logic to reverse engineering, which i don't think there is in
this case.

Dental picks are probably expensive. I picked up a nice 4 piece pick
kit somewhere a couple years ago for maybe 5 bucks.
Just came in handy for digging out a crumbling plastic hose nipple
threaded into an aluminum intake manifold.
My Dremel kit was pretty expensive, but hey.

 

[Scott Dorsey]

Michael A. Terrell <mike.terrell@earthlink.net> wrote:

"trader4@optonline.net" wrote:

On Mar 26, 4:09 pm, Bimmer Owner <dontask...@mymail.com> wrote:
On Tue, 26 Mar 2013 19:41:47 +0000, Bimmer Owner wrote:
Can someone circle the resistors for me? I would think they would be fairly
decent wattage so they would be very easy to see, but I don't see any
resistors.

I 'think' (but I'm not sure) that these are the resistors in series:
http://www5.picturepush.com/photo/a/12516343/img/12516343.jpg

If they are resistors, I've never seen any that look like that.

You've never seen strips of nichrome in a space heater?

Bosch has done the nichrome insert power resistor for many years; I know
that they used them in the turn signal flasher in the late seventies when
they first went electronic. They aren't really very good resistors but
they are very cheap.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

[Scott Dorsey]

In article <kisss2$jpd$7@news.albasani.net>,
Bimmer Owner <dontaskfor@mymail.com> wrote:

On Tue, 26 Mar 2013 15:04:51 -0400, tm wrote:

Here is the Elmos 10901D chip of my FSU as I cut it open today.
http://www4.picturepush.com/photo/a/12515632/img/12515632.jpg

Are those the two transistors sitting on top?

Actually, it's the same transistor, which broke in half while
I was attempting to get the black rubber eraser stuff off of it
to read the numbers.

It's really going to be HARD to read those numbers now...
http://www4.picturepush.com/photo/a/12516062/img/12516062.jpg

Okay, there is a TO-220 package that is split open there, with the
backplate on the right and the cover on the left. Can you chip off
enough of the araldite from the cover to be able to read the numbers
on it?

Or, could you get a good picture of the die which is left on the piece
on the right? We might be able to identify it with a sharp photo of the die...
although from what I can see from the fuzzy photo it does not look like a
very happy die.

If it is actually a MOSFET it will look like this:
http://www.panix.com/~kludge/fet1.jpg

(That's a package that is a little bigger than the TO-220, but you can still
see the channel down the middle of the FET and the overheating damage to the
source.... the three leads have been torn off in the unpotting process though.)
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

 

[trader4@optonline.net]

On Mar 26, 5:38 pm, "tm" <No_one_h...@white-house.gov> wrote:

trad...@optonline.net> wrote in message

news:3d3144f3-a011-49e6-a07c-e6e576e0185a@5g2000yqz.googlegroups.com...
On Mar 26, 3:31 pm, Bimmer Owner <dontask...@mymail.com> wrote:

On Tue, 26 Mar 2013 14:56:21 -0400, tm wrote:
Any evidence it was checked with a scope?

Yes.

This quote below is verbatim from this location:
http://www.bimmerfest.com/forums/showpost.php?p=6536514&postcount=131

Hi, After soldering the lost/refound component,
remaking the joints of the 2 mosfet and testing the FSU alone with an
oscilloscope, here are my observations:

- the FSU works again

- there is no PWM ,

/You said you tested the FSU alone.  If so, how can you
/say there is no PWM signal between the car and FSU?

/ the gates signals are continuous voltage only , this is the reason
/why it heat so much its aluminium box... In fact there is no point on
/the board where square signals are present. Can somebody check its own
/FSU if it's the same ?



- the 2 bridges are in fact 2 resistors 10 milliohm used to balance the
currents between the 2 MOSFET and balance the power also. The mesure of
the DC voltage on those resistors can be used to evaluate the current of
the blower and its worn state.

/Say what?  10 milliohms is .01 ohms.  How could that
/possibly balance the power to a motor in a 40 amp circuit?

Not to the motor idiot. To the transistors.



- I guess the principal duty of the computer on the other side is
switching off the power transistors if the control voltage goes under 1V.

/Which makes no sense at all.

Certainly not to you.



I put the FSU back in the car and it still work, I don't know if it will
last long. because of the heat...

Olivier

http://www.bimmerfest.com/forums/attachment.php?attachmentid=306784&d....

/It seems they last at least a few years.  Maybe it's like
/gas.  You buy it and you go so far.   I think you're in way
/over your head here;

But not yours?

No, because I'm not the one trying to reverse engineer
an electronics module in a car, that contains among other
things, an unknown 16 pin chip, without benefit of any of the
necessary tools. You guys don't even know what the interface to the
car is, whether it's analog or digital, etc. And you don't even have
an oscilloscope to look at
anything with.

Oh, BTW, if you're all so smart, how come I was the
first one to find out for you that the 16 pin chip number
you had is a vaild one for a real chip?

 

[jim beam]

On 03/26/2013 08:20 PM, Michael A. Terrell wrote:

jim beam wrote:

On 03/26/2013 10:41 AM, Michael A. Terrell wrote:

jim beam wrote:

if it's just a two-layer board, maybe. assuming you get the specs on
the chips of course. but you'll need more than two units and a whole
lot of patience trying to reverse the schematic if it's 4 or more
layers. and you still don't achieve anything more than having a broken
light bulb in your hand.

what you need to do is get the operational capacities of the /working/
unit, and work with those. that the unit is a black box is completely
irrelevant.


Yawn. I worked with 16 layer boards at a factory troubleshooting
defective, new boards that cost over $8,000 to stuff.

fantastic. could you condescend to help these guys wit their project
then? or are you just here to whang your donger around?


No, I'm not like you. I have worked in Electronics for 52 years. I
could draw the schematics, but I would need a handful of bad modules and
the time to do it right. Just like the kU band microwave audio, video,
and data terminal hardware I worked on that's in orbit aboard the ISS.
It takes hands on effort to reverse engineer a design.

so what you're saying is that you're just here to piss and moan because
you know how to help, but won't.

and credentials don't work on usenet - they're completely uncheckable
and many are bogus. what matters is whether you can walk the talk.

as for having stuff in orbit, i don't have anything, but two of my best
friends do. the difference between them and you is that they're not
jaded and they're actually helpful.

Bomarc has reverse engineered a lot of automotive modules:

http://www.bomarc.org/basement/viewtopic.php?f=1&t=6&sid=8ee707756ef37b24ff5aa633f1b4548a

The one you want might be on their lists.

that at least is vaguely useful, but you could have come up with that 20
posts ago.


--
fact check required

 

[Michael A. Terrell]

jim beam wrote:

On 03/26/2013 08:20 PM, Michael A. Terrell wrote:

jim beam wrote:

On 03/26/2013 10:41 AM, Michael A. Terrell wrote:

jim beam wrote:

if it's just a two-layer board, maybe. assuming you get the specs on
the chips of course. but you'll need more than two units and a whole
lot of patience trying to reverse the schematic if it's 4 or more
layers. and you still don't achieve anything more than having a broken
light bulb in your hand.

what you need to do is get the operational capacities of the /working/
unit, and work with those. that the unit is a black box is completely
irrelevant.


Yawn. I worked with 16 layer boards at a factory troubleshooting
defective, new boards that cost over $8,000 to stuff.

fantastic. could you condescend to help these guys wit their project
then? or are you just here to whang your donger around?


No, I'm not like you. I have worked in Electronics for 52 years. I
could draw the schematics, but I would need a handful of bad modules and
the time to do it right. Just like the kU band microwave audio, video,
and data terminal hardware I worked on that's in orbit aboard the ISS.
It takes hands on effort to reverse engineer a design.

so what you're saying is that you're just here to piss and moan because
you know how to help, but won't.

Yawn. I don't have access to any defective modules. I don't know
anyone at the local BMW dealership to ask for failed units and I'm not
going to buy a new module to destroy for a whiny piss ant like you.

and credentials don't work on usenet - they're completely uncheckable
and many are bogus. what matters is whether you can walk the talk.

You can't even crawl.

as for having stuff in orbit, i don't have anything, but two of my best
friends do. the difference between them and you is that they're not
jaded and they're actually helpful.

Then tell them to reverse engineer it for you. Or can't they 'walk
the talk', either?

Bomarc has reverse engineered a lot of automotive modules:

http://www.bomarc.org/basement/viewtopic.php?f=1&t=6&sid=8ee707756ef37b24ff5aa633f1b4548a

The one you want might be on their lists.

that at least is vaguely useful, but you could have come up with that 20
posts ago.

And you couldn't so you piss and moan. I couldn't remember their
name, since I hadn't seen one of their print ads for over 20 years. I
looked them up, when I did.

--

Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.

Sometimes Friday is just the fifth Monday of the week.

 

[jim beam]

On 03/27/2013 09:45 AM, Michael A. Terrell wrote:

jim beam wrote:

On 03/26/2013 08:20 PM, Michael A. Terrell wrote:

jim beam wrote:

On 03/26/2013 10:41 AM, Michael A. Terrell wrote:

jim beam wrote:

if it's just a two-layer board, maybe. assuming you get the specs on
the chips of course. but you'll need more than two units and a whole
lot of patience trying to reverse the schematic if it's 4 or more
layers. and you still don't achieve anything more than having a broken
light bulb in your hand.

what you need to do is get the operational capacities of the /working/
unit, and work with those. that the unit is a black box is completely
irrelevant.


Yawn. I worked with 16 layer boards at a factory troubleshooting
defective, new boards that cost over $8,000 to stuff.

fantastic. could you condescend to help these guys wit their project
then? or are you just here to whang your donger around?


No, I'm not like you. I have worked in Electronics for 52 years. I
could draw the schematics, but I would need a handful of bad modules and
the time to do it right. Just like the kU band microwave audio, video,
and data terminal hardware I worked on that's in orbit aboard the ISS.
It takes hands on effort to reverse engineer a design.

so what you're saying is that you're just here to piss and moan because
you know how to help, but won't.


Yawn. I don't have access to any defective modules. I don't know
anyone at the local BMW dealership to ask for failed units and I'm not
going to buy a new module to destroy for a whiny piss ant like you.

i don't know who you think you're talking to, but i have consistently
advocated /not/ deconstructing this unit. it's not worth it when cost
of replacement isn't that high or you can build an alternate controller
that will be more reliable.

and credentials don't work on usenet - they're completely uncheckable
and many are bogus. what matters is whether you can walk the talk.


You can't even crawl.

at least i can follow a thread without being a crotchety old fart.

as for having stuff in orbit, i don't have anything, but two of my best
friends do. the difference between them and you is that they're not
jaded and they're actually helpful.


Then tell them to reverse engineer it for you. Or can't they 'walk
the talk', either?

i don't /want/ to reverse engineer it any more than i want to repair
broken light bulbs. you were the one bragging about how easy it was. i
said it wasn't. and when it comes down to walking the talk, you won't.

Bomarc has reverse engineered a lot of automotive modules:

http://www.bomarc.org/basement/viewtopic.php?f=1&t=6&sid=8ee707756ef37b24ff5aa633f1b4548a

The one you want might be on their lists.

that at least is vaguely useful, but you could have come up with that 20
posts ago.


And you couldn't so you piss and moan. I couldn't remember their
name, since I hadn't seen one of their print ads for over 20 years. I
looked them up, when I did.

i guess we should be grateful...


--
fact check required