U4 Pin 6 damaged - question

[t56tr]

Greetings - new user here.

I m finishing up assembling an ms3 board for use with a turbo ls build - it will also be using the ms3x for sequential fuel (as things progress).

Despite my soldering skills being about average or hobbyist level, I found some of the small components to be a bit challenging. Despite this, things seemed to be going fairly well and clean.

When I was about to install U4, I discovered one of the holes already had some solder in it. I didn't have a wick, and things spiraled out of control trying to clean the hole out and I somehow butchered it. The hole wound up having no ring left on both sides of the board. I decided to try and install u4 anyway, but quickly realized that I could not get any solder to stick to the board - it would just run down the leg/pin. Finally, I got the hole to plug with solder by going easily from both sides. Now it just about looks like every other soldered pin, maybe with a bit more bulk or dare I say glob to it.

Questions-(assuming if I get lucky enough to not have screwed anything else up and everything tests Ok..)

1)I am about to power the board and do the preliminary tests according to the assembly instructions, and then with the stim (jimstim). Will any of this testing let me know if the pin 6 connection is ok?

2)Is there any way I can test to find out if it is good?

3)Since I will be using the ms3x, does it even matter if that pin connection is not right?

Thank you for your help in advance.

[Six_Shooter]

1) It could let you know, since U4 pin 4 is the input from the CPU to drive the injector outputs. (U4 is a MOSFET driver IC. What this means is that one bank of (main board) injector drivers will not work if there is a problem with that connection.

2) You can use a DMM set to continuity to test between the leg of U4 and another point on the board where that trace goes, such as R17.

3) If by using the MS3x you mean that you will be using the injector outputs on the MS3x board then, no this probably won't matter, unless you are planning that output for another function.

[t56tr]

Thank you for the response -

Just to clarify - in your response you stated "u4 pin 4". I was asking about u4 pin 6...was that a typo?

Also, you stated to check continuity between u4 and R17. I was assuming that meant u4 pin 6 to r17 but do not get any continuity there. I do however get it from between u4 pin 6 to left side leg of D17.

Would that indicate its OK?

Thanks again...

[Six_Shooter]

Not a typo... brain fart.

Looking at the schematic, pin 6 is the power supply input (12 volts), and I believe the only reason that you would get continuity between pin 6 of U4 and the left side of D17 (the cathode) is because that would be the ground plane, which might be finding continuity through D21 to ground or possibly through U4 itself. I have not testing this connection myself, so I can't say that what you have found is good or not. When you say you have continuity here, is that 0 ohms resistance, or is there some resistance there?

You could check between pin 6 U4 to the right side of D3, and if that shows good continuity then I'd say you're ok. But the continuity to ground from pin 6 has me a little worried without testing that myself.

[t56tr]

I am not using a high end meter, but from U4 pin 6, to left side of d17 is 0.

I checked the other recommendation, pin 6 to right side of d3 and basically same reading.

Same for left side d17 to right side d3...

[t56tr]

Update - following the build instructions I plugged the board into stimjim and so far it has passed all of the recommended voltage tests etc (including 4.75 @ tsel). I do not have enough experience to know if this helps me w pin 6 but atleast things are going in a positive direction.