MSefi.com read only forum (Jan.15,2018)

I started to build ms2 and when i got to step 21 i got in a bit of trouble .. i soldered Q4 in place and about 5 mins later I realised that it has to go out .. there was a black box which sad that if you will be using PWM IAC Q4 is not to be soldered .. so I took it out of place and jumped 3 wires from the Q4 location to TIP120. Then as I connect the stim to the pcb there is a voltage drop and on the cpu socket pins 39&40 there is no 5V ......

Anyone knows what this might be ?

thanks
neil

I've not poured over the schematic to see if this could be the reason, but the track pads for these small transistors are very close together so a danger of bridging them exists. Have you checked for shorts?

I'm not trying to teach granny to suck eggs, but a powerful magnifying glass and lots of light can be needed to show up such faults by eye. The merest wisp of solder can do the evil deed. Or a stray strand from the wires linking the TIP120 to the Q4 socket.

by shorts you mean on the TIP120 ?? whn i check with a multimeter with the continuity function, it doesnt beep !!

neil_zazza wrote:by shorts you mean on the TIP120 ?? whn i check with a multimeter with the continuity function, it doesnt beep !!

No - I mean on the MS PCB, where you removed the original transistor.

Yes, I checked the connections on the pcb on there is no continuity as well !!

i have just read the troubleshoot section !

I have no bridges over the solder, all the components seem to be in order and i have no voltage across the U5

thanks
neil