MS3 first testing stage probleme

[paulstarn]

Assembling V3.0 board
When i power MS3 board thrue pin28 and ground, i blow the 3 amp fuse.
Did the tests that where recomemended
( diodes are all the right way, Q9 and Q12 are not grounded, cannot see any solder bridges , C16 17 22 and 14 are on the right way also )

I then removed U5 Q12 Q11 Q5 R38 Q9 Q3 Q1 and R37 ( Q16 was not instaled )

Now powering the board the fuse doesn't blow, i then reinstalled U5 and i get all the power at the right places on the 40 pin socket.

Put back on Q12 and everything is ok

When i put Q11 the fuse blows

Now the board is as the pictures but Q11 and Q3 are not instaled , when i put either of the 2 on, the fuse blows.

Pics coming, as soon as i figure out how.
Paul

[paulstarn]

Pics of board

[paulstarn]

Back side

[paulstarn]

Is there some kind of step by step trouble shooting procedure , that i can use to determine what is the probleme with my board.

Paul

[DaveEFI]

Have you got a Stim - or are you testing on the car?

[paulstarn]

I had a Stim, but i damaged it connecting to this board ( it was working fine last July ).

I am at step 13.5 testing stage of the MS3 assembly instructions
I connected the Stim and was getting 2Volts everywhere that i should be getting 12V and 5V
I checked pin28 of db37 connector comming from Stim and only 2V are comming out, and i have a solid 12V going into Stim
I decide to test the MS3 board using pin28 and ground, a 1amp fuse and it blows right away, i then try a 3 amp fuse and it blows also.

You can read my first post to see what i did next.

This is my 3rd MS that i assemble, the first 2 where MS2, on one of them i had a injector curcuit failure and used the DYI autotune procedure to trouble shoot and managed to fix it.

What are my options now, can this be trouble shooted ??

Paul

[DaveEFI]

An MS and Stim doesn't take as much as 1 amp, so if a 1amp fuse blew you have a fault somewhere. That it appears to be in both injector circuits is odd to say the least, as they re pretty well designed to prevent abuse.

I'd repair the Stim and get everything working on that first. Use a power supply than has overcurrent protection at about 500mA. So no risk of blowing fuses or doing other damage.

[Marek]

Dear Paul,

For all of the components that you have two of, check them with a multimeter that they have the same characteristics as each other. That way, unless both are broken, it'll be obvious that one of them is broken. All transisitors behave like a pair of diodes connected together with a common pin.

Take a look at the schematic, so you can see what to expect when one component is connected to another and what and what isn't connected.

Q3 and Q11 are the TIP42s for the flyback clamp circuits and should be identical to each other. They are PNP power transistors where the centre pin is also connected to the main tab and this is to be grounded, so it is safe to use the metal screws on the TIP42s. The other transistors need insulation from ground.

What you can do is build one of the injector drivers up completely and see whether that performs. If it doesn't, substitute in the other unused sister component - e.g. if the Q11 transistor "fails", then swap in the Q3 transisitor in its place and see whether that too fails. You can also do that with Q12 vs Q9.

Hopefully you can then isolate whether the transistors are bad (different to each other) or the circuits are bad (solder bridge, dry joint, etc).

Consider also, that as a temporary measure, just for test purposes, you can swap any NPN transistor with any other OR swap any PNP transistor with any other:- for example Q22 and Q23 can swap for a Q3 and Q11 as they are all PNP transistors (the arrows point inwards - see schematic).

kind regards
Marek

[billr]

Be cautious playing "mix-and-match" with those TO-92 transistors. There are many different pin-outs for that basic package; you need to check for the specific P/N.

[Marek]

Absolutely - I'm not suggesting you simply throw them in anyhow, but make sure that the base, emitter and collector pins are in their correctly assigned places.

Thanks for pointing that out.

kind regards
Marek

[paulstarn]

Hi

I thinck both TIP42 are dead, i have an order to digikey for new ones.
I will complete one of the driver circuits and when the TIP42 comes in , i will test.

As for the STIM that was damaged with the MS3 board that was shorted when the TIP42 where in place, i thinck that the 3.3V regulator is dead (also on order ).
I have a question opened on the jbperf.com site asking for help, but my post there doesn't even show up ( i'm assuming all the posts are moderated and eventually my post will show up and somebody will respond).

I will keep you updated as i continue my tests.

Paul

[paulstarn]

Ok, so i received the new TIP42.

As suggested, i completed one of the injector circuits, the only transistors required to complete the circuit where Q13 and Q15, i then connected 12V to the MS3 board and i get the proper voltage to the 40 pin socket.

Now i reinstalled Q11 and the 1 amp fuse blows when i connect 12V to the MS3 board.

So i'm back to square one.

Anything else i should be trying or looking at.

Thanks
Paul

[DaveEFI]

That, at least, is progress. Having both injector drivers with the same fault was odd to say the least.

If you refer to the schematic for the injector driver and notes on that, you'll see the driver consists of a basic one plus the current limiter and flyback clamp.

The injector driver should work without Q11 in circuit on your stim. Did it?

[paulstarn]

My STIM died when i connected it to the board, all test are done via pin28 and ground directly to MS3 board (always using a fuse ).

I will be using the MS3X expansion card , this is going in a 6 cyl Subaru engine EZ30R.

Can i continue the assembly and run this MS3 WITHOUT Q3 and Q11 installed.

Paul

[DaveEFI]

If you read the notes on the schematic page, you can decide whether you'll be OK without current limiting and or flyback control.

Personally, I'd want to find out what the fault is.

[paulstarn]

If my understanding is correct, by using the MS3X expansion card, i am not using any of the main board injector circuits

MS3 says 14 amp and can drive hi-z or low-z injectors.
MS3X says 5 amp and can only drive hi-z injectors ( need to add on stuff to drive low-z)

So, can i run this MS3X without Q3 and Q11 without causing any damage if i drive the injectors from the MS3X card.

I would love to find the fault on this board, but my electronics knowledge is limited, this is my 3rd MS i assemble, on the first 2 i added extra coil drivers, i converted coil driver for non-ignitor ones, did some trouble shooting, but all that, was documented and i was following step by step instructions.

Paul

[Marek]

Dear Paul,

If you are not planning on using the two mainboard driver circuits, then you don't need to populate the main pcb with any of those driver components.

Since you have built one good mainboard driver circuit, why not transfer all of the components from the good circuit to the other (maybe bad?) circuit. Since you know the components are good, it should tell you whether your fault was component or board related. If it works with the same components on the other driver circuit, then you can build up the first good circuit with fresh components.

As you are using MS3X outputs, you don't need to, but it's be nice to have a fully functioning board and some understanding of where the fault was.

kind regards
Marek