jleidel

All, I've been working through an interesting project in our [my company's] circuit/electronics lab. Thanks to `soontobered84`, I have a nicely fried fan control module from an S4->newer 928. Thankfully, the folks are also gear heads [Cobra kit, 308 Ferrari, etc]; so they graciously reverse engineered the entire circuit board for us. Typically, owners will replace the MOSFET's [aka, "fets"] in the unit. Rather that putting together a simple fix, we decided to reverse engineer the entire circuit in order to upgrade it to modern components. In order for us to calculate the appropriate costs, I would like to gauge the community interest in buying/transferring their S4 fan control switch to a brand new circuit design [fabbed on a modern process].

I _do not_ yet have any costs. Its highly dependent upon volume. It will likely be competitive with or less than current used/refurb models.

Thoughts//Comments?

BTW, SeanR is a ******.

User 4221

If I may, I would add my $0.0928.... Most semiconductor suppliers today have automotive qual'd parts that are designed to operate up to 175C junction temp. For the FETs, Infineon, ON Semi and International Rectifier have good stuff.

For the logic, I would look at Freescale and ON Semi.

Also, today's ceramic caps (MLCC) have enough energy storage capability so electrolytics that dry out and fail.

yardpro

interested

jleidel

Logic for Freescale and ON Semi? We're not looking for ARM Cortex A8's. Most of the logic parts are simple 'and' gates. They're easily accessible from TI or ST Micro. If we consolidate logic, we're still into small TI EPROMs or ST Micro units.

928 at last

You're new here. We generally don't even discuss anything less than military grade, combat tested components for our cars.....

I'm interested...it's just a matter of time...

SeanR

Sweet John, glad to see you have taken this on. A few if us have place bets on who in our DFW crew would do it.

jleidel

We have the whole circuit mapped out... time to condense and see what the fab costs are locally. The board is a simple, two layer unit. It shouldn't be terribly expensive to have farmed out. Stay tuned...

dr bob

John--

The 'weakest link' seems to be the FETs themselves. Will your modern redesign use something different for those final output pieces?

jleidel

Depends... modern FETs are much more resistant to heat and normal wear/tear. To that end we may use similar, but much more modern FETs. The individual doing the circuit rework is actually an expert in power bus technology, so I trust his judgement on the power circuit design [he is also restoring a Ferrari 308, so he understands the implications of vehicle circuits].

ALKada

John, would this cure the "magic blower" issue and other issues we have with the A/C head unit? If so, I would be interested.

kingsmen11

I've had two units go out on me this past year, so I would be up for a couple of new units. Thanks for the heads up.

Dictys

There is a few of us out here that are certainly interested, we seem to have a lot of these units failing at present.

ammonman

I'm interested. As Rob said, it's only a matter of time before I have to repair my control unit. I am partial to keeping the flap system working as designed. It is part of the cool factor for me.

Mike

jleidel

Sounds like we have a reasonable quorum for a small fab run. In my experience, most of the local fabs here in DFW don't like running boards in less than quantities of 20. [different for larger/more complex boards]. The nice thing is, these boards are single layer, two sided units. Very easy to build.

dr bob

John, add me to the interested list. Will the new boards/circuits rerofit into the existing housing?