Abe's NB-MSII Adapterboard/PnP - Page 12 - Miata Turbo Forum - Boost cars, acquire cats.

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Old 09-18-2009, 03:17 PM   #221
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Heh, sorry. Been busy.

Ok, the easiest thing: Use your DMM, and measure the current from one side of the resistor to the other.

It's odd mine drove it no problem and yours does not. My guess would be we just need to swap that ressitor with a smaller one.

I don't know how many mA the processor is good for. But, let's pretend... No, I'll go look up what the transistor needs. BRB
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Old 09-18-2009, 03:43 PM   #222
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Ok, the smartest answer:
Leave R19 as is (or even go a tinsy bit bigger)
Populate Q4 with stock MS-II stuff, if available
Then you'll need a pull up (to 5V), small, say 100 ohms.


OR

You should be able to put the TIP120 (can you get me the part number so I can check the polarity) in the same hole in my board - removing the part I sent. The issue is there's a HUGE variance in the gain on the part I used. Some have a gain of 60, some as low as 5. So, if you got a 5 and I got a 60, that's explains it.

It looks like I'll have to get this straight pretty quick. I'd rather tackle the in-the-case mod so no one who's already built their board has to tweak it, but either would work fine.
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Old 09-18-2009, 04:00 PM   #223
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That figures.

Part # of the TIP120 GKOHQ VW CHN 638

I bought it at radioshack, part# 276-2068

It looks like the manufacturer is STmicroelectronics, part# 497-2539-5-ND at Digikey.

Last edited by Marc D; 09-18-2009 at 05:24 PM.
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Old 09-18-2009, 05:52 PM   #224
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Awesome, will look at it right now. So, it looks like the MS is laid out poorly here as well. Go figure. You have to redo SO much to get this working. Technically they are blowing the spec, the chip is only rated for 2.5mA (Thanks Joe!) but their circuit draws about double that.

Looks like I found a candidate part which is insulated, has easily enough gain, can handle something ridiculous like 8 amps, and fits in the same hole, all of which can be comfortably run by the MS... I guess I'll order a stack of these. Anyone who wants them let me know I'll send some out. You SHOULD upgrade the resistor from 1k to at least 2k. I'd suggest replacing R19 with a 2.2k ohm OR desoldering/cutting one side, and putting another 1k in the other hole, then soldering them together - so they are "in a row" (series), adding up to 2 k.

Huh, interesting:
Quote:
Laboratory tests on a limited number of samples indicate, when using the screw and compression washer mounting technique, a screw
torque of 6 to 8 in . lbs is sufficient to provide maximum power dissipation capability. The compression washer helps to maintain a con-
stant pressure on the package over time and during large temperature excursions.
Destructive laboratory tests show that using a hex head 4−40 screw, without washers, and applying a torque in excess of 20 in . lbs will
cause the plastic to crack around the mounting hole, resulting in a loss of isolation capability.
Additional tests on slotted 4−40 screws indicate that the screw slot fails between 15 to 20 in . lbs without adversely affecting the pack-
age. However, in order to positively ensure the package integrity of the fully isolated device, ON Semiconductor does not recommend
exceeding 10 in . lbs of mounting torque under any mounting conditions.
Guess you REALLY need to be gentle on these, the plastic cased ones.


Marc: going to look up this tip120 you have and get back to you in a minute.
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Old 09-18-2009, 06:00 PM   #225
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Ok, Marc, it looks like the TIP will drop right in. If it gets hot, you'll have to insulate it when you heat sink it, but that's no big deal. Whatever fix you do, you'll pretty much have to do the same thing for the EBC side. But if you want to wait till I supply alernate parts on the EBC go ahead and use the TIP.

Also, when/if you heat sink it, if the heatsink doesn't touch anything else electrically live then you can skip the insulating.
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Old 09-18-2009, 06:11 PM   #226
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Thanks for the quick reply.

Im ging to head to my local radioshack to pick up some 2k 1/8w resistors, I dont have any lying around. Ill definitely do anything to protect the MS chip from damage. Those damn things arent cheap.

As for the TIP, im thinking of laying it on the proto area with a heat sink that radioshack sells, then just run some wires to the pins on the board. Its easier to desolder the wires than it is to desolder whole transistors. If the idle works good from that point, I will run it for a while. I would still like to see which transistors youll be sending us for alternate candidates.

Those J13007 transistors you sent us are like, impossible to find. It was difficult to find a datasheet for it in the first place.

As for the EBC, I thought the MS was controlling it? The transistor spot where the EBC is empty.. Did you mean the Spare/VVT section?
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Old 09-18-2009, 06:31 PM   #227
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yes yes and yes, basically.

There's nothing wrong with adding one resistor, but certainly putting a 2.2k in it's place is fine as well, looks cleaner. I wouldn't bother unless you're going shopping anyway.

Yeah, the NPN's I sent were just the best specs I could find without being $8 each. Of course, I only looked at the best case gain not the worst. My bad. :-(

The new part is basically a slightly upgraded T120 only with the full plastic case and somewhat better numbers, a better match for what the MS puts out, it'll play more nicely with the limited driving of the MS-II (hence work better with the 2k resistor). Since the idle is pulsed, with the TIP you're probably ok with the 1k that's in there. Not ideal if building from scratch, but it'll work.

If you want, you can just desolder the part I sent, put the TIP in the hole*. It'll probably be fine. It's really only 300 mA and most of the time a 20-30% DC anyway. If it's hard to desolder, cut the old part off close to the board then push** out the legs one at a time. This is safer for the board.

edit: Yes, I meant for the spare. :-)

*I said put the tip in the hole. HA! Get it?
** Make sure the solder gets melted. Don't force anything through. Use a toothpick or something to push (or solder sucker if you have one), something metal will cool the solder, unless it's the iron tip, and make it hard to do.
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Old 09-18-2009, 06:40 PM   #228
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Cool.

So ill just go ahead and try the TIP120 with some wires and heat sink and let you know the results.
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Old 09-18-2009, 06:59 PM   #229
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Annnd...

Voíla!

It works. Idle works perfect. Transistors need to be replaced for sure ^_^
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Old 09-18-2009, 07:31 PM   #230
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*whew*

Awesome, glad to hear it. Well, sit tight with your wires, and when I get the new parts I'll send you a couple. They are likely going to show up... mid next week.
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Old 09-18-2009, 07:34 PM   #231
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Got it.

Ill go ahead and upgrade the transistor to the one youll be sending along with R19, but ill leave it as it sits for now.
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Old 09-19-2009, 12:38 AM   #232
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And its mounted!

And the funny thing is, I didnt use anything keep it where its placed. If i want to remove it, I just push it off to the side with a good hard push, and it falls right out the side.

The MS sits on its side, right above the steering column. i am surprised there is THAT much room up there. Ill take a picture of it tonight.

As far as the board is concerned, there is no real place to put it anymore, si i zip tied it to some wire harness hanging right next to the underdash kick panel. Clears my feet, no problem. Whoohoo!

I drove it around the block. God... Smooth as butter. No hick ups. Then again, I'm runing uber rich. But no more CAS drop outs for godsake.

Going to take the car for a spin so I can tune my out-of-boost sections.
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Old 09-19-2009, 12:40 AM   #233
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PICS!!! :-)

I need to do a full retune soon, I want to turn on all the odd additions to the code lately, map sampling, AFR table, etc. Might take a while though.

Congrats. Maybe you can get the first speeding ticket on one of my boards.
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Old 09-19-2009, 12:52 AM   #234
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Heres the pics, sorry they are through my cell phone.

EDIT: weird, they disappeared..

Anyway here.


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Old 09-19-2009, 01:13 AM   #235
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Hey Marc, could you please upload pics directly of the cased adapter board? I want what you have...
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Old 09-19-2009, 06:48 AM   #236
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I posted a bunch of pictures of it on page 7 of this thread, and how to make it.

https://www.miataturbo.net/forum/t36300-7/#post450693
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Old 10-16-2009, 09:57 PM   #237
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I thought I would bring this thread back to life, seeing that this is more of hardware related, rather than an MSQ related post.

Ok, so I got the transistors last week abe sent, and the capacitors came in today.

I desoldered the capacitors and added the new ones I ordered. I also soldered in the new transistors that Abe sent.

Impressions:

Transistors are working fine. These are the ones! My idle didn't change due to the increased current, but they are working just fine.

Capacitors seem to work good. I haven't had a chance to do a "quick" start or a long drive somewhere, so I can't give any information about the changes in these issues that I was having previously. I am noting that it does seem to work. Ill post up again if the issue on sync loss arises again or if they dont.
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Old 10-16-2009, 10:19 PM   #238
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Whew! Glad to hear it. I know the PNP's worked in my test mule but it's always great to see something "go" in real life. Very curious about these caps. If they work for you I'll try a set myself.
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Old 10-16-2009, 10:29 PM   #239
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abe, ive been meaning to ask,

Is there a 5V reference point on your board? Im pretty sure there is one, but I wanted to double check which ones.
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Old 10-16-2009, 10:58 PM   #240
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You can certainly grab it at the jumper block, on either side. I would grab it away from the OEM connector, so it's still live even if you pull the jumper. But, after some soul searching, I didn't make any external connection to it.

If you guys get ideas for things you think new boards should have, let me know. It won't help you much, but I'll work it into the next run of boards. :-\
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