Root cause insight into the common BMW blower motor resistorfailures

Bimmer Owner > wrote:
>On Thu, 21 Mar 2013 09:47:31 -0400, Scott Dorsey wrote:
>
>> I don't see why it is so hard to unpot one of these things and repair them
>> directly, especially if it's a semiconductor failure.
>> Put a bigger transistor in there.
>
>Here are pictures from the last half dozen who tried that approach:
> http://www2.picturepush.com/photo/a/...g/12470740.jpg
> http://www4.picturepush.com/photo/a/...g/12470742.jpg
> http://www2.picturepush.com/photo/a/...g/12470745.jpg
> http://www4.picturepush.com/photo/a/...g/12470747.jpg
> http://www5.picturepush.com/photo/a/...g/12470748.jpg
> http://www2.picturepush.com/photo/a/...g/12470750.jpg

These are kind of sloppy jobs. But it's clear there are two TO-3 devices
there which have been removed in all of those photos.

>One problem with "put a bigger xtor" is that nobody on this planet
>has produced a decent circuit diagram of the FSU.

Well, has anyone got docs on that mystery IC there? It's from Elmos
Semiconductor, but it's not a standard Elmos part number on it, so it's
almost certainly a custom, since it doesn't look like anything in their
standard book.
--scott

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