It Lives.
#1
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Well, very slightly anyway. After two evenings' worth of casual soldering and a trip to Fry's to buy a USB-RS232 adapter, my MS-I came to life and took its first tentative step into the world by telling me its battery voltage (11.81) as per Step 41.
![](http://img505.imageshack.us/img505/4158/itlivesne4.jpg)
Soon, she will Squirt!
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Soon, she will Squirt!
#10
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Originally Posted by AbeFM;
And what's that tiny little black thing where the MS-II belongs?
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Originally Posted by reddroptop
Iomega USB-RS232 adapter?
Originally Posted by elesjuan
Nice power supply Joe.
Originally Posted by Ben
So it was a 2 beer project?
So far, the official beers of this project have been Red Hook ESB and Road Dog Porter. Though Abe has strongly insinuated that if I come down to his place we will decant some fine homebrew, possibly to include a Milk Stout. (hint, hint)
Originally Posted by The_Pipefather
Nice! I'm gonna be starting soon as I'm done with my ******' thesis.
#13
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Man, I miss the 80s.... 'Course, even then it was all C. Anyway, at least this way if you wire it wrong and fry the chip, you won't lose anything of value.
'Cept when Abe comes around. Then it magically comes in cans.
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So far, the official beers of this project have been Red Hook ESB and Road Dog Porter. Though Abe has strongly insinuated that if I come down to his place we will decant some fine homebrew, possibly to include a Milk Stout. (hint, hint)
Weight Savings. I'd think it was obvious.
#14
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The only heatsunk devices I'm currently planning to omit in the finished build are Q9 and Q12 (INJ PWM) and possibly Q16 (High-current IGN) which will free up space on the heatsink for the EBC and WI FETs.
#15
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Originally Posted by AbeFM
You gotta check your hard drive power supplies. They are generally reasonably well regulated, and supply amps upon amps. Even the little one I'm using is 2amps. I could give you one of my old ones from a palmtop or something...
'Cept when Abe comes around. Then it magically comes in cans.
Well, to start.
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#16
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I felt really bad about recycling Q16 for boost control (but I hope you noticed how I did it, it really came out slick if I do say so myself) - I like knowing I can run bare coils whenever I want.
Then again, as Braineak has been quick-and-right to point out, converting to toyota coil-on-plug is cheaper than getting plain jane coils and throws a hell of a spark.
Then again, as Braineak has been quick-and-right to point out, converting to toyota coil-on-plug is cheaper than getting plain jane coils and throws a hell of a spark.
#17
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I think it's an IOGear. No brand-name on the adapter, but it's got P/N GUC232A on the label, and when I googled it I came up with the IOGear website. Since it didn't come with a driver (open box special) I D/L'ed theirs and it works (That tablet PC is running Win2K.) So far, Megatune seems happy with it. I haven't loaded MSnS-E yet, just using the base B&G code at the moment.
Kinda sucked forking over the $$$, but never have any issues and never will.
If it was open box unbranded, you got a good deal for sure.
#18
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And it begs a question- if you can drive a VB912 directly off the CPU, then what's the deal with U4 needing to be there at all for the main injector drivers?
I'm curious about something- you've removed and jumpered R37 and R38, but it looks like Q14 and Q15 are still there. Looking at just the INJ1 channel for simplicity, my understanding of the schematic is that it is the voltage drop across R37 which causes Q14 to operate and turn off Q1 in the event of an over-current condition. Without the resistor, Q14 might just as well not be there.
#19
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You're using Q16 (a VB912) as the boost control driver? I hadn't noticed that previously. Very interesting... I'd been planning to use an IFLZ44, but your way is cleaner.
And it begs a question- if you can drive a VB912 directly off the CPU, then what's the deal with U4 needing to be there at all for the main injector drivers?
I'm curious about something- you've removed and jumpered R37 and R38, but it looks like Q14 and Q15 are still there. Looking at just the INJ1 channel for simplicity, my understanding of the schematic is that it is the voltage drop across R37 which causes Q14 to operate and turn off Q1 in the event of an over-current condition. Without the resistor, Q14 might just as well not be there.
And it begs a question- if you can drive a VB912 directly off the CPU, then what's the deal with U4 needing to be there at all for the main injector drivers?
I'm curious about something- you've removed and jumpered R37 and R38, but it looks like Q14 and Q15 are still there. Looking at just the INJ1 channel for simplicity, my understanding of the schematic is that it is the voltage drop across R37 which causes Q14 to operate and turn off Q1 in the event of an over-current condition. Without the resistor, Q14 might just as well not be there.
Oh yeah! I REALLY didn't get the directions when I did that. It said "remove R37, and jumper" or something like that, and I didn't know if it meant to jumper it or remove it. I remember reading and re-reading. This was the very last thing I did before I got the schematics (which I can never find!!!!). I meant to revisit it. I really wanted to replace those, mount them on the back of the board - but I wanted to check into what they were and what they did. They have a "front" and a "back" - are they just resistors, or are they somehow polarized? I was mounting them on the back of the board when I kept changing my mind about how they should be mounted (polar or not) and ended up snapping off the leads on one. So, I can solder to the stub, but then I figured the instructions made it sound like most people don't use them at all.
I really wanted to put them in, and I can't imagine they really need a heatsink. Anyway, without the jumper, Q1 might as well not be there. :-) So, I guess I could take out the useless Q14/15, but I'd really rather just put R37 & 35 back in. As best I can tell, they really just ARE resistors, so in the words of Space Ghost: Now what was the point of sanding my face off?
#20
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Originally Posted by AbeFM
What I did was use the circuit on the board. There's good fat traces everywhere you need them (it's an ignition circuit) and it keeps space free on the proto area. I just jumped one "resistor" and subed a 10k for what went in the hole. Check my build thread for details, but it's pretty clean and you don't have to mount the chip sideways to clear the d-37
Oh yeah! I REALLY didn't get the directions when I did that. It said "remove R37, and jumper" (...) This was the very last thing I did before I got the schematics (which I can never find!!!!). I meant to revisit it.
R37 and R38 are just resistors, and they're non-polarized. Specifically, they are 0.05 ohms, being used as current shunts. Looking at this portion of the schematic (the INJ1 overcurrent protect) here's how it works:
![](http://img265.imageshack.us/img265/9408/injprotectvk2.png)
U4 drives pin 7 high when it wants to turn on Q1, which is the primary injector driver. "INJ-1" is the incoming (or outgoing, depending on how you look at it) connection from/to the injector, which has +12 on the other side of it. The injector comes into Q1 at pin 2, and it conducts to ground through pin 3.
As the current flows through R37 on the way to ground, there is a slight voltage drop across the resistor. Notice that the base of Q14 is connected at the junction between the ground side of Q1 and the "hot" side of the resistor. So any voltage drop across the resistor will show up as a positive voltage on the base of Q14.
So long as the current flowing through Q1 (and therefore through R37) is within reason, the voltage drop across R37 will be sufficiently small as to not trigger Q14.
If the injector shorts out however, causing the current through Q1 to rise to an unacceptably high level, then the voltage drop across R37 will increase until the base-emitter saturation voltage of Q14 (about 700-800mv) is achieved. By my calculations, this should happen somewhere in the neighborhood of 14-16 amps. When Q14 turns on, it will pull the trigger pin of Q1 to ground, causing Q1 to turn off and therefore interrupting the short circuit condition. It's a really clever design.
So when note 1 says you can "Remove and Jumper" R37 and R38, they mean just that. If you need to free up some space on the heatsink, you can remove the resistors. In doing so you must place the jumper in their holes so that Q1 and Q5 still have a path to ground to operate the injectors. This defeats the overcurrent protection circuit, since there is no voltage available to trigger Q14 / Q15 anymore.
I'm going to leave those in place, and instead remove Q9 and Q12. Those are the PWM damping circuit, and I don't plan to run PWM injection control since I already have hi-z injectors and I intend to run HR code which doesn't support injector PWM. That will give me space for my WI FET. Of course, the EBC FET will be going in the Q16 hole via your neat little trick
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