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For the same price, it looks like we can get a separate unit: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
This is how people are. At some point intellectual curiosity takes over.Maybe it's time to look at this thing like gas and brakes...
You put gas in, you go so far. You put one of these
blower modules in and you go for a few years again.
It's not like they are a $500 or $1000 puter. Don't they
cost like $50? I mean how much is time worth trying
to reverse engineer it.....
Not really, it's feeding the motor with variable DC from that integratorOn 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.
I don't think Fluke makes much in the way of current probes for DC withOn 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.
No, there are two transistors bolted to the heat sink. That's why the heatOn Mon, 25 Mar 2013 14:55:02 -0400, Scott Dorsey wrote:
Okay, notice on the lefthand photo, there are two sets of three solder joints
on the lefthand side of the board, which show signs of recent rework. There
are TO-220 transistors attached to them, which are behind the board and you
cannot see.
Ah, I see what you're talking about and I've circled them in this photo:
http://www3.picturepush.com/photo/a/12511526/img/12511526.jpg
Like a good detective, you've seen something that I had not seen.
What you said makes sense. However, I have never heard of anyone
removing two transistors from that board. I wonder if those two
sets of inline pins are just the connections to the heat sink?
No, the spacing is consistent with a TO-220 transistor pair, and if it'sBut, what puzzles me is that nobody has ever mentioned removing
transistors from those two spots. Therefore, I suspect they're just
anchor posts, since the solder is clearly removed in the autopsies.
It's not a switcher. And those transistors may not be MOSFETs. But thereAs a general rule, MOSFETs are not used for linear current control. It is
more looking like this is a switcher (PWM) though I dont see an inductor.
Could be they just use the motor for that.
Agreed.If you can see any numbers on the devices, it will help. Also, the solder
sure looks like RoHS shit tin.
i understand that - and variable voltage is the problem. the secondaryIn 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.
It's not much different than a big rheostat in terms of starting
torque. It's just more expensive and less reliable and quieter.
--scott
way to understate - those things are insanely expensive. otoh, there'sBimmer Owner <dontaskfor@mymail.com> 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.
I don't think Fluke makes much in the way of current probes for DC with
appreciable sensitivity. The i1010 is sensitive enough for this sort of
job, but not for a lot of other things you might want. They do make some
fancy intelligent probes but they're all more expensive
than just buying
a Fluke clamp meter like the 365.
That said, I have a cheapo Extech 380947 and it's not built like the Fluke
but it's sensitive enough to detect small ground leakage currents.
--scott
if you want your purchase to be useful for automotive, you wantOn 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, $109.95
there's been another post - the output has been scoped. it's linear."Bimmer Owner" <dontaskfor@mymail.com> wrote in message
news:kir99g$hpn$5@news.albasani.net...
On Tue, 26 Mar 2013 04:22:30 +0000, Bimmer Owner wrote:
Ah, I see what you're talking about and I've circled them in this photo:
http://www3.picturepush.com/photo/a/12511526/img/12511526.jpg
Looking more deeply, I find ANOTHER reference to the two MOSFETS,
which, are clearly the two transistors shown in the wiring diagram
that you had surmised must exist (by detective work).
Here's another quote which went along with this photo below
that mentions the unknown-as-yet MOSFETS:
http://www3.picturepush.com/photo/a/12511566/img/12511566.jpg
olivier577 said:The 2 MOSFET drain and source are tied together but the gates are
differents
On the picture , one of the component is gone with the rubber foam : its
look like transistor : black with 3 pins ( it 's not bipolar
transistors ).
It happen to me also : the component gone so easily that I didn't
realize it,
maybe it is the issue for that FSU.
It is only while I compare to other pictures in the forum that there was
a lack of component on my board.
fortunately I found it together with the rubber foam parts, so I will
solder it back later
As a general rule, MOSFETs are not used for linear current control. It
is more looking like this is a switcher (PWM)
now you're guessing.though I dont see an
inductor. Could be they just use the motor for that.
you're not telling the difference from a simple visual. sorry.If you can see any numbers on the devices, it will help. Also, the
solder sure looks like RoHS shit tin.
One key question in all this is if the interface from car toBimmer Owner <dontask...@mymail.com> wrote:
On Mon, 25 Mar 2013 14:55:02 -0400, Scott Dorsey wrote:
Okay, notice on the lefthand photo, there are two sets of three solder joints
on the lefthand side of the board, which show signs of recent rework. There
are TO-220 transistors attached to them, which are behind the board and you
cannot see.
Ah, I see what you're talking about and I've circled them in this photo:
http://www3.picturepush.com/photo/a/12511526/img/12511526.jpg
Like a good detective, you've seen something that I had not seen.
What you said makes sense. However, I have never heard of anyone
removing two transistors from that board. I wonder if those two
sets of inline pins are just the connections to the heat sink?
No, there are two transistors bolted to the heat sink. That's why the heat
sink is there, to cool those two power transistors.
But, what puzzles me is that nobody has ever mentioned removing
transistors from those two spots. Therefore, I suspect they're just
anchor posts, since the solder is clearly removed in the autopsies.
No, the spacing is consistent with a TO-220 transistor pair, and if it's
a linear pass regulator like it appears to be, there needs to be a big
transistor somewhere. Also, of course, there is the heatsink.
That IC is only control logic, it just takes some mystery input signal and
produces a variable voltage for the transistor base. Those two transistors
are doing all the hard work. BUT, if you want to replace the device with
a retrofit one, you need to know what that mysterious input signal is.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
But is that a clean DC level or a pulse width modulated signal? If it wasOn Tue, 26 Mar 2013 09:10:56 -0400, Scott Dorsey wrote:
BUT, if you want to replace the device with a retrofit one, you need to
know what that mysterious input signal is.
All I know of the HVAC input signal is that it's a 2.0 to 7.8 VDC
signal from the HVAC controller, presumably to correspond to the
various levels of the fan blower motor speed.
The semi-conductors circled are not the MOSFET you are looking forTo my knowledge, nobody has ever posted a photo of what those
two MOSFETS look like, nor the part number.
Ah, so it's a plain old voltage divider?The mesure of the DC voltage on those resistors can be used to
evaluate the current of the blower and its worn state.
What does this sentence above mean?
with two resistors in series, the voltage across any one is a function
of its resistance and the current in the current in the other.
All I know of the HVAC input signal is that it's a 2.0 to 7.8 VDCBUT, if you want to replace the device with a retrofit one, you need to
know what that mysterious input signal is.
I don't even own a BMW. After this thread, I don't think I ever will.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!
All I know is that the HVAC controller sends a 2.0 VDC to 7.8 VDC signalOne key question in all this is if the interface from car to "resistor
block" is some kind of simple digital interface, ie it sends some bits
that get interpreted as "go to speed 3" or does it send a PWM signal.
The originals fail within about 5 years. I've had my second one fail inHow fast are these things failing for those that want to make their own?
This is one of the classic failure indications! Very very very common!The failure on that X5 resulted in the blower draining the battery
when the car was off. Blower ran fine. Only odd thing in retrospect
was that when the car was off, a couple times I heard a faint noise.
Exactly!one person figuring the failure mode out might save a
lot of people that grief.
But mostly it's just intellectual curiosity.
I agree that the Extech meters are a good buy for the money. I have theBimmer Owner <dontaskfor@mymail.com> 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.
I don't think Fluke makes much in the way of current probes for DC with
appreciable sensitivity. The i1010 is sensitive enough for this sort of
job, but not for a lot of other things you might want. They do make some
fancy intelligent probes but they're all more expensive than just buying
a Fluke clamp meter like the 365.
That said, I have a cheapo Extech 380947 and it's not built like the Fluke
but it's sensitive enough to detect small ground leakage currents.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
Your idea about testing it is correct, however a bad one can work fineOne key question in all this is if the interface from car to "resistor
block" is some kind of simple digital interface, ie it sends some bits
that get interpreted as "go to speed 3"
or does it send a PWM signal.