QDI4 Q2 protection

[rusefillc]

if you can tack a wire onto C32/C9 to look at, it may tell us something as well
8:40
(should be 1.58v)
8:40
or there abouts

Noxz
9:00 PM
put a 15A fuse with alligator clips.. from the frankenso, in.. and it blew within 1 second.. I also had DRIVEN hard wired to ground
9:01
so something is pinned to ground
9:02
oh, the 12v line.. from somewhere
9:06
iirc the only way to figure out what fried is to start taking stuff out individually.. right?
9:06
if nothing visible

andrey
9:10 PM
#95

#95 GDI4, GDI6 huge holes/vias for PT2001 and PT2000 main pads
can we do similar to microRusEFI maybe with 1mm diameter holes?
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https://github.com/[rusefi/rusefi-hardware](https://github.com/rusefi/rusefi-hardware)|rusefi/rusefi-hardwarerusefi/rusefi-hardware | Yesterday at 9:09 PM | Added by GitHub
#95

Noxz
10:02 PM
dinner eaten.. time to remove a component at a time until I find the broken one?
10:02
grantid I was just on INJ1/2, that narrows some of it down
10:02
but if the boost fet (Q2) is blown, that is much harder to get to
10:03
due to placement of capacitors
10:05
so it's either channel 1, or the boost section... or the PT chip itself, etc etc.. could be a few things

andrey
10:11 PM
my current state: injector clicks only once on bench, and green blinking turns into blue blinking
10:11
bench test is supposed to click three times

Noxz
11:16 PM
of course it was Q2 that was blown........
11:16
this has happened before.. we need to figure out some better protection for it

Noxz
2:11 AM
done soldering.. letting the board cool down before a re-attempt.. replaced Q2 with a BUK9230 from R0.3 board
2:11
but I didnt just take Q2 off.. Q2 was basically the last thing I removed.. lessons learned should have been applied, but it's such a pain of a location to get the hot air gun into

Noxz
2:41 AM
board does not seem to power on (when the fuse points are shorted with alligator leads) - but there is still plenty of resistance/non shorted on the 12v line (Q2 did not blow instantly)
2:41
will look at it more tomorrow

Noxz
2:58 AM
was testing out voltages on the regulators.. a small spark then the board powered up
2:58
so maybe some back-charge from when I was testing continuity
2:59
blinky blue..
2:59
I did not continuity check the pins this round.. will do that tomorrow I think

3:00
but yeah.. q2 fried

Message dev_di

[mck1117]

Q2 protection wasn't the problem, problem was floating sense lines for the boost converter current sense, see #101