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ECU unit

Viktor

May 8, 2017
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May 8, 2017
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Hi!

I have an ECU unit that behaves very strangely.

I previously "repaired" this unit by cleaning the board as there was signs of water, and it worked for a couple months.

Lately however, the machine began to shutdown after 20ish minutes of operation, and now it only turns on for like 1 minute before it warns about the ECU. If you try to start it again, it's just gonna warn you about the ECU, unless you keep it off for a little while, then it could let you start for a minute or so again.

I suspected since the problem seems to occur after a little while that it might be a temperature issue; So I have tried to use cooler spray to cooldown the components, without much luck. And, I also tried to heat them up without much luck.
So the problem seems to occur after some time, but changing the temperature around the circuit when this happens didn't seem to give any other result.

I also tried to resolder the input pins in case some of them had gone bad without much luck there either.

Based on the symptoms, is there anything I should look out for or perhaps some part that could cause this behavior? Or perhaps the ECU unit is faulty but the machine doesn't warn about it after being in operation for a little while? I have no idea.

Any ideas or suggestions is much appreciated.
 

Alec_t

Jul 7, 2015
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Could be leakage current somewhere it shouldn't be, perhaps causing a cap to charge or discharge over a long period. Contaminants between pcb tracks or between IC pins can provide leakage paths. Electrolytic caps can go leaky with age.
 

Viktor

May 8, 2017
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May 8, 2017
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Could be leakage current somewhere it shouldn't be, perhaps causing a cap to charge or discharge over a long period. Contaminants between pcb tracks or between IC pins can provide leakage paths. Electrolytic caps can go leaky with age.
Contaminants shouldn't be a problem as the unit is thoroughly cleaned. Any special parts that you suspect could become leaking?
 

Alec_t

Jul 7, 2015
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Apart from the caps, semiconductor devices can become leaky if stressed electrically or thermally.
 

Viktor

May 8, 2017
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Apart from the caps, semiconductor devices can become leaky if stressed electrically or thermally.
Is there any way to troubleshoot this without having to disconnect even semiconductor in the device? Perhaps using an octopus circuit and an oscilloscope and look for something suspicious?
 

Alec_t

Jul 7, 2015
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I guess that would depend on the characteristics of your octopus circuit. I've never used one. But leakage might occur only when the semi is under normal working voltage/current conditions, which I don't think it would be when testing with an octopus circuit. Tough one.
Another possible culprit would be a dry or corroded joint, which goes high resistance when thermal expansion has had time to take effect. Worth giving the ecu a close scan under high magnification.
 

kellys_eye

Jun 25, 2010
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Pics please.

There are often devices bolted to the case (heatsink) that, if corrosion gets behind them, can allow the device to overheat/shutdown.
 
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