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Hi,

I've been gone tru 3 instrument clusters for the FORD THInk Neighbor and I would like to know if there is a way to fix them. All 3 seems to burn out at the same place. There is a mosfet L540NS in the center of the board. Top of this mosfet I see the circuit burned out.




On one instrument the whole area is black seems like it was a big blow out. The one on the image I just see the circuit peeled away broken (red circle)


I'm thinking replacing the L540NS with a new one and repairing the circuit.... I wonder anyone has attempted to repair with success. All information is appreciated.


Thank you
 

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I'm thinking replacing the L540NS with a new one and repairing the circuit.... I wonder anyone has attempted to repair with success. All information is appreciated.
If you have had several fail the same way the problem is probably not on the circuit board but in whatever that component is driving. FET's tend to fail shorted. If the foil is flashing off the board then there is likely a problem somewhere else that is causing the FET to fail and then the overcurrent flashes the circuit board trace like a fuse.

I suspect that changing out the FET and repairing the trace could result in a working board but I doubt this will correct the overall issue.

You might look around and see if this is a common problem with that vehicle.
 

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I'm thinking replacing the L540NS with a new one and repairing the circuit....
I'm not certain, but I think that the FET part number will be IR340C (perhaps search for IR340; the C is likely a temperature grade code, "C" = commercial).

[ Edit: the above is wrong; thanks for the correction, Tess. It seems that the 340C is a combined date code and assembly line code, as in 2003 (or 1993? and soon 2013?) week 40, assembly line C. Though presumably the lot code (6D and 2C) would tell you the assembly line. Not what I'm used to. ]
 

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Discussion Starter #5

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If it is a congenital design problem:

Maybe change out the FET, repair the trace with some wires, then have that circuit drive an external FET with a dedicated fuse. If it blows then, it will be easier to work on.

Miz
 

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I've had problems with various dash systems over the years, sometimes it's as simple as running a soldering iron over the joints on the dash to repair it.
 

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I was recently presented with a blown Think cluster and challenged to fix it. It was a fun puzzle which came with monetary reward as well and this page helped get me started. In the end I spent maybe 20 hours on it, replaced more than 15 blown semiconductors and managed to get it all working. Next time I might be tempted to replace the elaborate switching supply (which makes me uncomfortable since it only uses 100V parts on a 72V nominal system) with a simpler Topswitch based design that I use on the Zilla. But this time I fixed it to the original design since I didn't understand the circuit well enough until it was running. The mechanic and I have replaced the charger with a Delta-q that should avoid any future uncontrolled overvoltage events.

btw: The Delta-q charger we got has a large green inhibit line that is pulled to battery + (72V) via a small NC relay when the unit is unplugged. As far as I can tell, and contrary to the diagnostic notes in the online Think manual, the Think cluster wants to see the charger inhibit wire (Gr/bk) pulled to 72V- when the car is unplugged and that line should never be pulled high (it has a 12V internal pullup in the cluster). Therefore I also made a small modification circuit to invert that signal. That bundle will be installed near the charger.

Since I found this on a google search, I figure maybe posting my notes and collected documents here can help someone else in the future. These notes are just scribbled sections of schematic that I reverse engineered. I made little effort to turn this into a DIY project since it requires pretty deep electronic knowledge to utilize these notes. Beware that file sizes are relatively large, I did not scale them. The information may be incorrect and is very incomplete. I offer no assurances of value or any support with it, but it's free and if you don't like it you can have your money (though not your time) back. :)

I've put up a folder here with all the documents:
http://cafeelectric.com/public/ThinkNeighborInstrumentCluster/

Hopefully this can help someone keep old EVs running.
 

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Thank you for the great information.

How is the fix holding up? Did you end up making any further improvements?
No news is good news. I hear the customer recently replaced a blown motor, (he hopped it up and tows airplanes with it) but the cluster seems fine still.
 

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Hi:
I will appreciate, if anybody can tell me where can I find repaired 2002 Ford Think Neighbor City Instrument Cluster for sale (1).

Best Regards,



cefelipe
 
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