Please Help. Votalge question while assembling V3

[jet47]

I've been building in stages and when I last left off I had the correct 5 volts to the cpu pins.

I went on to build the communication steps and that tested correctly.

I then got to the point in which you test with megatune. I couldnt ever get it to connect.

Now I've gone back and checked voltages on regulator and have almost full voltage on both outside pins and less than 1 ohm on middle pin.

I get no voltage when checking the cpu pins unless I have the multimeter grounded to stim battery, then I get full voltage at each cpu pin 1,2,19,20,31,&32.

It sounds like I have a short or a bad component, has anyone seen these symptoms before. I would like to know before unsoldering pieces at a time.

Thanks,

Josh

[Matt Cramer]

Got a couple questions to narrow down the scope of the problem.

I get no voltage when checking the cpu pins unless I have the multimeter grounded to stim battery, then I get full voltage at each cpu pin 1,2,19,20,31,&32.

Ok... what ground points for the multimeter don't work?

Did it load firmware OK?

[jet47]

Matt,

Thanks for replying, None of the cpu grounds seem to work. If I hook the multimeter to 1 and 2, I get 0 volts, if I hook to 19 and 20, I get 0, and 31 and 32, I get 0 volts. However if I ground the multimeter to the negative side of the battery, and touch the positive lead to any of the above pins, I get full voltage(9 volts).

I tried to install the firmware with Download 2.00 and didn't suceed. When I verified, it responded recieiving 'S', but when trying to download the firmware it failed the wake up call, saying it expected '4', but returned ' '.

Thanks again, let me know if you have any pointers, or need other info.

Josh

[jet47]

Also I forgot to ask if ordered the kit from DIYAutoTune would I have to install the firmware for MS1 or would it already be installed?

[Matt Cramer]

MS1 CPUs have B&G firmware pre-loaded; MS2s do not. In either case, you would need to resolve the ground pin issue. I would check the U1 socket for cold solder joints, stray flux or solder blobs, anything that could be causing trouble.