MJL v3 problem

Post by **brentp** » Tue Mar 02, 2010 6:23 pm

I recall one unusual occasion where the oscillator faulted, drawing excessive power. I would recommend removing that as well (carefully, so you don't damage board traces) then re-measure current draw. Normal current draw should be very low- I don't have my notes, but it should be much less than 200mA

van · Post by **van** » Wed Mar 03, 2010 10:43 am

Hi Brent
I repalced max 232 , and put socket first

. Tried controler on car , but I didnt see spark advance . Curent draw was 400mA

. LED controled by user outputs were doing some crazy stuff . Without + to controler , all LEDs are ON , and when I connect + ( turn on controler ) , just one last LED are on ( that on pointing 5500 rpm

). Is it common to see ULN is letting - out , when controler is OFF (disconnected + ) ? Can controler work when ULN is not present on board ?
I will try to replace oscilator also ... If that doesnt work , I will component by component , to see what is causing current draw .

van · Post by **van** » Wed Mar 03, 2010 5:09 pm

And update :
I checked current draw with microcontroler out , it's 40mA . When i put microcontorler on current draw was 400 mA . So its microcontroler , or oscillator . I think its first one

What are my options for repaire ?

NITROPIXIE · Post by **NITROPIXIE** » Wed Mar 03, 2010 5:29 pm

To check if the oscillator is drawing alot of power you could use a standard 1000 Ohm resistor instead of the processor chip. Here you would take the processor chip out of its socket and run a resistor from where pin 4 of processor chip would be to pin 16. I have included a diagram. Then test then current again.

From what you have said i would expect the processor chip to be at fault but you never know.

van · Post by **van** » Wed Mar 03, 2010 7:10 pm

I did that , and I saw 40mA , with and without resistor . I measured 180 Ohm on board power supply to processor ( gnd and 5v ) , and 28 Ohm on same processor pins ( 1 & 16). I dont know much about electronic , but my verdict is that processor has gone .
I am in doubt ; how this has happen ? I switched car off . Car was in garage for dec. & jan. I came , and turn it on , and MJL didnt wont to advance timing .
I dont know what to do , can I order new processor ? But I didnt find root of problem , so suspect it will ruined another processor ... Is it better to buy new v4 kit , insted of repaire ?

van · Post by **van** » Thu Mar 04, 2010 6:27 pm

I was investing some data about 68HC908KX8CPE , to find power usage . I found that processor is 8 MHz , and my oscilator is 16Mhz . Is it ok ?

Post by **brentp** » Thu Mar 04, 2010 7:06 pm

The clock rate is correct. It seems like your processor may have died. let us contact you offline for further help...

van · Post by **van** » Thu Mar 04, 2010 11:57 pm

Thanks Brent