Adamw Posted August 24, 2023 Report Share Posted August 24, 2023 Yeah, if the scope is still showing 0.9V with A5 & A7 shorted then there is some internal issue with the ecu I think. Let me talk to the hardware team for some thoughts. atlex 1 Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 25, 2023 Report Share Posted August 25, 2023 Ok, I think I have some explanation for the apparent ground offset. There was apparently a small number of G4X plug-in ecu's manufactured early this year with a supposedly equivalent alternative op-amp used in the trigger scope circuit due to a supply shortage of the normal part. It was discovered after a short time that this was causing a variable offset to be generated in the triggerscope capture. The calculated affect was an average offset of 500mV, with about +/- 500mV range, so yours is sitting near the worst case. The good news is this out-of-spec part only affects the voltage recorded by the trigger scope, the trigger conditioning circuit, thresholds, and signals seen by the processor will all be seeing the correct voltages and working as normal. We can arrange collection of the ecu if you wish to have the part replaced now, or you can continue finishing/tuning etc and arrange repair at a more convenient time. Quote Link to comment Share on other sites More sharing options...
atlex Posted August 25, 2023 Author Report Share Posted August 25, 2023 46 minutes ago, Adamw said: Ok, I think I have some explanation for the apparent ground offset. There was apparently a small number of G4X plug-in ecu's manufactured early this year with a supposedly equivalent alternative op-amp used in the trigger scope circuit due to a supply shortage of the normal part. It was discovered after a short time that this was causing a variable offset to be generated in the triggerscope capture. The calculated affect was an average offset of 500mV, with about +/- 500mV range, so yours is sitting near the worst case. The good news is this out-of-spec part only affects the voltage recorded by the trigger scope, the trigger conditioning circuit, thresholds, and signals seen by the processor will all be seeing the correct voltages and working as normal. We can arrange collection of the ecu if you wish to have the part replaced now, or you can continue finishing/tuning etc and arrange repair at a more convenient time. I'm under no pressure to complete tuning so would rather arrange connection now than later. There's a ticket open with tech support. I'll pass my address details over on that and then proceed to decant the ecu from its case. Alex Quote Link to comment Share on other sites More sharing options...
atlex Posted October 19, 2023 Author Report Share Posted October 19, 2023 DHL dropped the fixed ECU around earlier today.. results are clean and good :-) Voltage offset now looks normal and the signal is clean! <B Link <B Quote Link to comment Share on other sites More sharing options...
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