advice needed please !!

danncus · Post by **danncus** » Sun Apr 23, 2006 5:28 pm

HI

i have been running a V2 board for a few months - with a TPS and sequential shift light(using shift light and outputs 1,2& 3.)

all has been very good.

until i tried to make the wiring perminent into the molex and shorten the wiring with heatshrink etc before using it at a sprint next sat.

when i powered it up all the LEDs lit up for a few seconds and then went out accompanied by a familiar burning smell!

on inspection Q6 has blown

questions

1. is it likley that the replacment of the transistor will restore the unit? (does anyone have a maplin ref #)

2. i can't find a wiring fault - can anyone diagnose what my have been at fault?

thanks

MartinM · Post by **MartinM** » Sun Apr 23, 2006 5:32 pm

If you're fairly sure it's Q6 that's let its smoke out, then remove it from the board.

Then I'd (re-)wire up the MJLJ from first principles up - ground, +12V, PIP and SAW - and verify it works OK. Then put your shift lights back on, one at a time - it should work except that PGM2 won't work. If that's OK, then replace Q6 and you should be OK.

Possible cause - pin 14 of the Molex directly to +12V would kill Q6...make sure you haven't connected any of the other prog. outputs or the shift light directly to +12v - that will kill each output transistor in turn!

danncus · Post by **danncus** » Sun Apr 23, 2006 6:09 pm

thanks for the prompt reply Martin

i found and fitted a 2222 transistor but it is still dead

i dont have my laptop at home

i also measured voltage on the tps in/output and got 1.8v and 12v

oh dear!

i have put the car away incase i do somthing i will regret!

is Q6 just switching pgm 2 ?

i should have left the Â£#%$Â£ thing alone!!