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Bought a used MS-I box that has minor damage, need advice


junglist

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I bought this used MS-I V3.0 board from a member here for a very fair price. Upon opening the unit I noticed that one of the "chips" or what have you is broken/chipped on the circuit board. In the attached picture I've circled the broken piece in red. If it helps at all I can read "CKTF" "0445" on the piece in question.

 

I wanted to ask the MS guys on here if they know what that particular chip/piece does and if its damage will be or is an issue? Is it something that I can remove and replace easily for a reasonable cost? Can I get that piece seperately if I need to? I'm going to join and post on msefi.com also to hopefully get input from there as well.

 

I do not have a stimulator yet to test the box to see if it fully functions but I was told that when it was removed from the car it was in that all was fine and the guy was upgrading to SDS.

msprob_thumb.jpg

ms2_thumb.jpg

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Ok got it. The U4 is part of the injector circuit.

 

v3pcb_4.gif

 

Check out this circuit and make sure there's nothing else that needs replaced. If you don't feel confident about doing it yourself, let me know. I can check it out for you and make any repairs needed; And I'm cheap.

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That's not an MS-I that's an MS-II. I can't remember off the top of my head what the U4 chip is, but I would replace it and fully test the rest of the components in that circuit to ensure it's not going to get damaged again when you power it on.

 

How can you tell? Here's another picture.

ms1_thumb.jpg

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2 things:

1. the daughter card sitting on top of the board is the MS-II processor board.

2. It has all of the transistors across the top of the board including the ignition driver.

 

Ok, I see that now...duh on my part. It even says MSII on the daughter card but in such tiny lettering that I wasn't paying attention to it.

 

I see that the U4 part is only $2.06 from digikey so that is good. Ryan, the guy I am doing my build with is pretty proficient with circuit boards and soldering and such.

 

Thank you very much with the help.

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Pretty rare for U4 to be burnt like that. I would check to see if there's any damage to Q1, Q5, Q14, and Q15 as well if that happens. That is the injector driver circuit.

The picture is a little fuzzy, but it really doesn't look burnt to me, it looks like it actually took and impact and cracked. That may have been exasperated by the crappy solder joints and God only knows what else. Who put this thing together?

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After you do repairs I would be inclined to send the unit to someone with a stim board to make sure the basics all work. Not saying your skills are in question, but just to make sure nothing else is damaged. Nothing is more frustrating than troubleshooting an install with a questionable/untested megasquirt unit.

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After you do repairs I would be inclined to send the unit to someone with a stim board to make sure the basics all work. Not saying your skills are in question, but just to make sure nothing else is damaged. Nothing is more frustrating than troubleshooting an install with a questionable/untested megasquirt unit.

Agreed 100%

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The picture is a little fuzzy, but it really doesn't look burnt to me, it looks like it actually took and impact and cracked. That may have been exasperated by the crappy solder joints and God only knows what else. Who put this thing together?

 

I think you are correct...it does look like it took an impact and cracked. I can't see any burn marks around it or anywhere else on the board.

 

I just asked who I bought it from and he said it was bought from diyautotune.com and was running fine when they removed it. It sat on a shelf for 3 months before he sold it to me so whatever broke that piece must've done it then. Not a big deal if it's something easily replacable.

 

I assume it would be worth my time/money to buy or build my own stimulator unit to test this once I replace the U4? I'm sure shipping roundtrip just to have someone look at it and test would be close to $30 and thats 2/3 the price of a stimulator kit.

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Pretty rare for U4 to be burnt like that. I would check to see if there's any damage to Q1, Q5, Q14, and Q15 as well if that happens. That is the injector driver circuit.

 

Here is a little bit clearer but much bigger picture. The best I can do with my camera that I have here at work.

msprob2_thumb.jpg

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Ok, there's a lot of residue around that right side of the chip. Check the circuit really really well. It could be a stress crack from overheating. That unit was not built by diyautotune. They know how to make good solder joints and the joints all the way around that chip and some of the adjacent components are horrible. I'd have never sent one out like that.

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Ok, there's a lot of residue around that right side of the chip. Check the circuit really really well. It could be a stress crack from overheating. That unit was not built by diyautotune. They know how to make good solder joints and the joints all the way around that chip and some of the adjacent components are horrible. I'd have never sent one out like that.

 

 

You are right, not from diyautotune as I was told. The inside bottom of the case has the guy's website address on it. I went to his site and he said he purchased the components from "Glen's Garage" and assembled it himself. So there is where the solder joint issues and whatnot come from.

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R19 has a poor solder joint as well. There is a whole bunch of components missing too, which may have not been needed for the builder's application, but you may need them.

 

I hope you got a great deal on it, because it needs work. Depending on what you paid for it, you might want to just buy a new fully tested v3.0 main board, and try to get your money back. Last thing you want is a questionable ECU when you are trying to do a new MS installation.

 

Pete

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  • 4 weeks later...
Pretty rare for U4 to be burnt like that. I would check to see if there's any damage to Q1, Q5, Q14, and Q15 as well if that happens. That is the injector driver circuit.

Matt, I have junglist's MS box right now. I've been going over this thing pretty close and here's what I have so far:

 

U4 - Obviously toast.

D19 - short closed. It was wide open to ground.

 

My battery died in my DMM after this so I don't trust any of the readings I got from here on. Also, The circuit trace from the negetive side of C16 to the ground leg of U5 was being held together by a giant ball of solder. The trace was pealed off the board. Once I get a 9V to replace the one in my DMM I'll know more, but as it stands it looks like this box took either a heavy voltage spike, or someone crossed a hot and ground lead during their setup. What are your thoughts?

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First repair all of the physical damage. You can bypass the damaged part of the PCB with wire. Replace all components that appear suspect.

 

Hook it to a stimulator and check all voltages before and after the 5V regulator.

Check to see if Megatune can see it. If so, check all the sensor inputs with the stimulator. You will most likely need a scope if these simple repairs and checks don't work.

 

Pete

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Oh I got all that. I'm just trying to figure out what could have caused all this damage. I've already cut the fried trace back and replaced it with a jumper wire. The only thing stopping me from powering it up with the stim is that I can't get the damned daughter board off. I don't want to find there's more problems and possibly blow that out as well. It's like the board is soldered in place, but the socket is there (albeit the socket is cracked and broken in places). I'm going to see if I can't find a chip puller at work to put some even pressure on it so it doesn't risk cracking. This poor board has been through hell, I think I cna bring it back though.

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