How to diagnose my MS-II daughterboard processor?

[EnricGuardiaSinfreu]

I'm back with more problems lol

When yesterday I was already running my engine and starting to tune fuel and spark tables I didn't expect that today when plugging my MS2 I would blow my board 0.5A fuse (after pin 28).


My MSII processor daughterboard doesn't work properly, when power MS, the 3 LED light up but don't stop and I can hear a continuos injection, also doesn't stop, not the cleaning pulse. The worst is there's no comunication with my computer. I've find out the schematics so I plan to check the daughterboard. My intuiton tells me that this is only possible with a burnt CPU. But where's the problem, U1? U2? U3? U4?

Seriously, I would like to pay 120€ for a new daughterboard and forget about this headache but I promised myself to not spend more money on this and to do it 100% DIY.


I'll check the polyfuses and probably the whole V3.0 board too.


Is possible the CPU to unconfigure? Should I try to reinstall firmware? any thread wih some good information about daughterboard troubleshooting? Any thread about flashing CPU? Do I need expensive tools for that? This is new to me.



Thanks x1000

[slow_hemi6]

Do you run things from the stepper driver or supply anything else from that fuse? If so you could draw more than 0.5A. 2 or 3A is what is shown in the core wiring diagram. http://www.msextra.com/doc/pdf/html/MS2 ... .4-14.html

[jsmcortina]

Loading firmware is covered in the Megasquirt2 Setting Up Manual.

James

[DaveEFI]

First check is to remove the daughter card and power up MS - to make sure the fault that caused to fuse to blow isn't elsewhere. If that is OK go on the check the various voltages. You'll find details in the manual.

If the daughter card is faulty, there are specialists on here who can fix it for a lot less than a new one. As was said, a stepper motor driver or circuit fault could cause the fuse to blow. You can isolate that by removing the 12v link to it. The rest of the board runs on 5v

[EnricGuardiaSinfreu]

I've checked V3.0 board, polyfuses okay, voltage on pins 32-31 , 19-20 , 1-2 are 5v and pin 16 is 12v.

All seems to be correct there.

When I power the board with the CPU plugged, (only 12v pin 28 and 1 ground, no inputs/outputs), 9S12 heats up.

Loading firmware is covered in the Megasquirt2 Setting Up Manual.

James

Would you try to load the firmware if cpu heats up?

Do you run things from the stepper driver or supply anything else from that fuse? If so you could draw more than 0.5A. 2 or 3A is what is shown in the core wiring diagram. http://www.msextra.com/doc/pdf/html/MS2 ... .4-14.html

I installed 0.5A fuse directly on my +12v trace after that trace burnt with a 5A fuse before Db28 pin. Used to work.


So... now if I want too keep this DIY (this is the real challenge) i need a new MC9S12C64AE chip which is about 12€, but the problem comes with BDM, this stuff is new to me and I see them from 30€ to 450€. Don't know if they're it will be compatible with this chip. TQFP soldering is a problem too.



So what do you guys recommend to me?
Which is the minium budget I need for a BDM that works with MC9S12? The programming process doesn't seem difficult, is it?
Can I solder that chip with a conventional soldering iron, some flux and a good pulse?


Thanks!

[jsmcortina]

For a one off repair it is almost certainly cheaper to get someone to fix this for you. The P&E BDM I have is very unreliable and a serious PITA to use.

James

[DaveEFI]

Yes. Unless already skilled in replacing this sort of surface mount processor and have the equipment to do it, best left to one who can. I have replaced one once - but life's too short. I did get it working, but only after patching the tracks I damaged removing the old one. And I've got many years experience of soldering.

[EnricGuardiaSinfreu]

P&E Multilink BDM are supposed to be the optimus interface to work with 9S12 and they're a pain in the ass too? I don't like to read that


Give me your opinion:

I can get MC9S12C64CFAE for 5€ from China, or for 15€ from UK (a lot faster shipping).
I can get a "cheap" used P&E SB HCS08/HCS12 Multilink Rev. C for less than 100€. I would like a cheaper interface but what I really need is something reliable with this chip.


So that's the same money that a new MS2 daughterboard from DIYautotune, but what happens if I burn again the processor? having the BDM, that's only 10 bucks more, risk/reward is better. Also the knowledge I could achieve from doing this by myself would be gold.


The only thing that pushes me away is BDM compability with the MCU and the process (possible errors while trying to unlocking the chip, failing when loading serial monitor or firmware, all it can go wrong but I ignore...)

I think I could handle soldering process with some flux, a diazepan and a lot of patience.


regards

[rickb794]

Nothing from the outside world should have a direct connection to a processor pin.

Then the processor can't get burned.

[jsmcortina]

Or you could send it to me for a repair. Typical cost is under £50.

James