Hi.
I've recently finished assembling a V3.0 board with an MS II processor and I'm running v2.684 firmware.
I'm having trouble with my tach signal, when I crank the engine I get an rmp signal of 6000 – 8000. I'm currently using a Bosch VR sensor with a 60-2 wheel on the crank.
I've tried adjusting R52, but the signal just changes to 70+ rpm, there's no transition, it goes directly from the first rpm signal of 6000 down to 70.
When I adjust R56 the time it takes to change from 0 rpm to 7000 rpm seems to become instantaneous.
I've checked all the components and I've checked for dry solder joints but everything seems to be fine.
Also, during cranking I measure a voltage across the VR sensor of 1.8V. Unfortunately I don't own an oscilloscope so I cannot get an indication of the signal from the VR sensor
I haven't tried to connect a resistor from VR ground to R56's wiper, as I'm not to sure if it will solve my problem. Also, everything seems to be fine when I use the stim.
Can anyone give me advice on what I should do.
Thanks.
VR Circuit Trouble
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