Root cause insight into the common BMW blower motor resistorfailures

On Mar 26, 5:38*pm, "tm" > wrote:
> > wrote in message
>
> ...
> On Mar 26, 3:31 pm, Bimmer Owner > 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/sho...&postcount=131
>
> >

Originally Posted by olivier577

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:

Originally Posted by olivier577

>
> > - 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/att...entid=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?

Michael A. Terrell > wrote:
" wrote:
>>
>> On Mar 26, 4:09 pm, 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/...g/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."

In article >,
Bimmer Owner > 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/...g/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/...g/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."

On 3/25/2013 10:56 PM, Bimmer Owner wrote:
> On Mon, 25 Mar 2013 17:34:25 -0700, jim beam wrote:
>
>> buy a clamp-on current meter
>
> I have a Fluke 75, so I'll have to see what clamp on DC current
> probes fit it.
>

Of all people, sears has one for less than $100 that does DC current

http://www.sears.com/craftsman-digit...p-03482369000P

as i recall, i think harbor freights clamp meters are AC current only
(like most are)

I am a fluke man too. Own at least 5 DVM's of various types.
Big fan of the 70's series. Tough, last forever if you take care of them

bob

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 **** 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=8ee707756ef37b24ff5aa633 f1b4548a>
>
> 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

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 **** 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 **** 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=8ee707756ef37b24ff5aa633 f1b4548a>
> >
> > 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 **** 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.

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 **** 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 **** 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=8ee707756ef37b24ff5aa633 f1b4548a>
>>>
>>> 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 **** 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

jim beam wrote:
>
> i don't know who you think you're talking to, but i have consistently
> advocated /not/ deconstructing this unit.


Apparently I'm talking to a blowhard troll.


> 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.


Ass. The first step in designing a replacement is to understand what
it is supposed to do, and how the original performed that function.


> >> 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.


Show us.


> >> 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.


Send me some defective modules, or quit trolling.


--

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.

Følgende er skrevet af Nate Nagel:
> On 03/25/2013 01:58 PM, Bimmer Owner wrote:
>> On Mon, 25 Mar 2013 07:55:03 -0700, jim beam wrote:
>>
>>> that reduces the probability of it being rohs
>>
>> What does ROHS mean?
>>
>
> Restriction of Hazardous Substances; that is, no lead (among other things.)
>
> http://en.wikipedia.org/wiki/Restric...nces_Directive
>
This does not count the hazardous issue of the soldering failing,
causing hazards to the users of the equipment :-(

--
Husk kørelys bagpå, hvis din bilfabrikant har taget den idiotiske
beslutning at undlade det.

Leif Neland > wrote:
>Følgende er skrevet af Nate Nagel:
>> On 03/25/2013 01:58 PM, Bimmer Owner wrote:
>>> On Mon, 25 Mar 2013 07:55:03 -0700, jim beam wrote:
>>>
>>>> that reduces the probability of it being rohs
>>>
>>> What does ROHS mean?
>>
>> Restriction of Hazardous Substances; that is, no lead (among other things.)
>>
>> http://en.wikipedia.org/wiki/Restric...nces_Directive
>>
>This does not count the hazardous issue of the soldering failing,
>causing hazards to the users of the equipment :-(

That's why there are exemptions for the military and telecom industry,
where it's actually important that stuff work properly.

What I find ironic is that the shorter lifespan of consumer gear caused by
the RoHS manufacturing has actually increased the amount of electronics
going into landfills, making worse the problem that it was intended to reduce.
--scott

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