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MBE 9A4 high voltage

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Have an MBE 9A4 that after a number of years or relatively trouble free running just decided to crap out. 

All the sensors into are reading max readings and the ECU itself says it's receiving 20.00v (presumably the max the channel can display).

Multimetering the wires it's getting 12v as expected.

Has anyone come across this before and can shed any helpful light on it?

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Hi can't help with what's gone wrong with it ,but this bloke might be able to have a look at it ,he's local to me and sorted my mbe 956     http://www.oddified.com/mbe912.php        he's called Ian, he'll only answers the phone in the morning's 

Tony 

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Long shot this, but does anyone have a list of what voltages they see on their loom with the 9A4?

I've tried wiping the ECU, disconnecting the 24v start system and still no joy. I get the below, 5v earth has me sceptical but just would like to know what each pin SHOULD be seeing...

Untitled-1.thumb.jpg.d287f960646661b40843ffd0f12099d6.jpg

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Did you open it and have a sniff? Looks like it's the 5V regulator that feeds the reference voltages, doesn't it.

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Hmm, on inspection of the board, I can see a broken/melted pin on the TLE 4470 G, says that is a "Dual Low Drop Voltage regulator"... Semi sure that was replaced about three years ago. Think it might have gone again.

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Hard to tell if that's been deliberately cut and bridged or if it's melted to that state. I had a quick look at the datasheet but couldn't immediately see what's going on there

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Do you have that datasheet handy? Would like to see it.

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Looks like it's obsolete, so might need to find some old stock or a pin- compatible version and hope the board and other components are ok (de-soldering is easy with hot air)

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Loads of them on eBay. Will see if I can get the solder/pins cleaned up and if that doesn't work, new chip time, if that doesn't work, urgh, new ECU...

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to clean the pins, you just need solder braid and a regular soldering iron to wick the solder away

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Get's weird. I found a photo from the initial failure of the chip. Can see the heat/failing of the arms into the chip (Dec 2015).

20151228_pic_of_board_reg_replace.jpg.b9fb8f88f547a3f83d4457fe61c52917.jpg

I have a receipt for the ordering of a replacement chip for (Dec 2015) it but then the trail goes dead. Furthermore, examing that pic above, to the current pic below an extra capacitor has been put in.

20190415_additional_capacitor.thumb.jpg.cd1dc88399a3aa0f5db29da491bf1142.jpg

I literally have no recollection, or idea of who would have the knowledge to do this. I'm totally confused :-/ Can't find any emails/messages for who did this work, if it was sent out, etc.

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Probably just clutching at straws, but the soldering doesn’t look well flowed to me. Might be worth a quick re-flow before trying anything else?

The shorted leg looks deliberate to me. It’d be a pretty unlikely scenario that resulted in what you see there IMO. The solder is still nice and shiny and even has traces of flux on it the look, not likely if it’s been cooking for a period of time., it would be grey and dull.

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Yep, that looks like a deliberate mod to me.

Is it possible that something's shorting the 5V reference line from pin 4 to ground somewhere in your loom? That would affect the reference voltage to the on-board ADC and every analogue reading in the ECU would then be out, which looks like your symptoms.

Can you power up the ECU off the car by connecting a low current 12V supply to the two +12V inputs with ground to one of the 0V lines, and see if you get 5V on pin 4 then?

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