D19 Very hot ??

[damon308]

Hi I have a MS1V3 Extra fitted 2 coil drivers and not sure quite what I done with my wiring but one of my Drivers at Q16 exploded to bits so D19 was now getting very hot after just being powered with stim for 20 to 30 seconds so I fitted a new D19 but still same very hot ??, I have carefully checked Voltages at chip socket ( chip Removed) at 1-20 - 32 I get 4.7 approx V so regulator is fine so I can not think what else to change, again any help appreciated, Regards DM

[DaveEFI]

D19 is a 5.6v zener to protect the 5 volt rail should anything go wrong. It will only get hot if it's seeing more than 5.6v and dissipating current So my guess is that 5 volt rail is shorted to something more than 5 volts somewhere.

[damon308]

D19 is a 5.6v zener to protect the 5 volt rail should anything go wrong. It will only get hot if it's seeing more than 5.6v and dissipating current So my guess is that 5 volt rail is shorted to something more than 5 volts somewhere.

Hi DaveEFI, that is what I though, but what as I can not see anything else that can be shorted out, so again any help appreciated, Regards DM

[DaveEFI]

Are you sure it is, in fact, the correct zener? 4.7v is a bit low for the 5 volt rail - and the wrong zener would explain things.

[damon308]

Are you sure it is, in fact, the correct zener? 4.7v is a bit low for the 5 volt rail - and the wrong zener would explain things.

Hi DaveEFI Thanks, yes I have just checked and it is the correct Zenner IN4734, I was assuming the Low reading was because of the drain ? I have also lifted D11 and D12 and fitted a new U5 the Voltage regulator, so again any help appreciated, Regards DM

[DaveEFI]

One thing I would advise against is replacing components without being certain they are faulty - all too easy to damage the PCB and make things worse.
If it was ok before, I'd be checking carefully for damage caused by your 'explosion'. BTW I'm not quite sure what you mean by "one of my Drivers at Q16" - are these additional coil drivers?
Sorry not to give more positive advice - it's not a fault I've come across.

[damon308]

One thing I would advise against is replacing components without being certain they are faulty - all too easy to damage the PCB and make things worse.
If it was ok before, I'd be checking carefully for damage caused by your 'explosion'. BTW I'm not quite sure what you mean by "one of my Drivers at Q16" - are these additional coil drivers?
Sorry not to give more positive advice - it's not a fault I've come across.

Hi DaveEFI, thanks again, yes I know what you mean but I am at my wits end trying to solve this problem so looking at the schematis and changing any likely components in same circuit that might have been damaged when it shorted out ???, Q16 is the Std Coil driver on all V3 boards and I am running 2 coil drivers so ( second one mounted on underside of Board temporally disconnected) 4 cycl wasted spark, and no it is not a fault I have come across before either as usually after a short I just replace D19 and all is fine, so maybe someone else on here has some Ideas for me to try, so again Thanks, Regards DM

[damon308]

Hi, Sorted at last with Matt at DIY's help, even though I had replaced D19 it actually turned out to be a Faulty one ??? so just fitted a another new one a everything is fine , so again Thanks for all the help, much appreciated, Regards DM

[DaveEFI]

Very unlucky, I'd say, to have two faulty ones.