HELP!!!no reaction of board after AREF mod

[Timmo6]

Hi,
My wikipage is here:http://www.vems.hu/wiki/index.php?page=MembersPage%2FMarteleurTim
After a few things I've done to the board, the board doesn't powerup anymore.
I've doen the following:
* soldered the AREF with a thin wire
* put a 30v Transient suppression diode in the injectorflyback
* made a new wireharness with use of most of the original wireharness
Since that the board won't give a sign when I try to connect to megatune nor the lcd gives a sign.
I've checked if the board gets its +12v and the grounds, everything seems to be allright.
I unsoldered the AREF-wire but still no reaction.
Did I do something wrong and how can I diagnose the problem further down?
Thanks for any help.
Tim

[rob@vems.co.uk]

Check the output of the +5v regulator

[Timmo6]

no +5v output measured
can it be I destroyed the capacitor while soldering the AREF?
thanks for the help!

[rob@vems.co.uk]

It could be that you are pulling +5v to ground.

Try removing the AREF link and seeing if the 5V springs back up - you may find that the fuse has blown, or the 5v regulator has packed up.

[Timmo6]

I already removed the AREF and nothing changes. Here is a pic of the AREF I soldered.

[rob@vems.co.uk]

Test the 7805,
First check that there is a 12V feed to it.
http://www.national.com/ds/LM/LM340.pdf
Then check that the output is 5V.

[Timmo6]

hmmm.... this becomes very technical for me but I will try to understand.
What is the 7805, and where do I find it and test it on the board?

[rob@vems.co.uk]

Its the component in the bottom right hand corner of this picture:
<-- There it is 

[Timmo6]

OK will do that. I first have to simplify my setup because the wireloom is still in the car so its not easy to test this way. I will eliminate every unnessesary wire of the connector to avoid misreadings etc.
I will update afterwards.
Tim

[Timmo6]

OK did some measurements:
Something is definatly wrong.
I have +12v at the connector pin25 when not connected to the board.
The output of the 7805 is not 5v but 1,48v.
I did some other tests as mentioned in the pdf file for "official build and test guide".
1. 5v main regulator = 1,48v
2. 5,6v supply voltage of the igbt-chip=0,56v
3. 5v output of regulator near place of second lm1815 = 0,03v
4. 5v PS2 supply voltage = 0v
5. Aref voltage =0,81v
6. 5v processor supply= 1,47v
7. LCD supply -8v, and 5v= resp. 0,38v and 0v
So what should I do next?
Thanks
Tim

[rob@vems.co.uk]

It looks like something is either: pulling the 5V down, which is going to be horrible to find.  Or that the regulator is dead.
If you can desolder the regulator's 5V leg and measure that you'll know which of the two it is.  The voltage between GND and the 5V output should be 5V if its 1.48v then it will be a case of replacing the thing.

Rob

[Timmo6]

The 5v leg is the big one on the end right?
OK will do that and reply.
Can it be that its the capacitor where the AREF wire is soldered on that is broken and pulling the 5v down now?
thanks
Tim

[rob@vems.co.uk]

I suppose that's possible - you may have a spare capacitor of the right size in the rescue pack, so try desoldering the cap before doing the regulator, and seeing if it brings the power back up.

[Timmo6]

UPDATE
I made a setup on the bench with a 12v battery and only 5grounds and the +12v supply attached.
Guess what,.... I had +5v at the voltage regulator output!
So something must be wrong in my wiring in the car.
Will do some more tests in the car and start with the connector with only 5grounds and the +12v connected, and so further on. Seems to be strange though.

[rob@vems.co.uk]

Are you saying that you only have Gnd5 attached?