Joe Perez

iTrader: (8)

I guess I'm not seeing what you're seeing? It looks fine to me.

The MOV is installed between +12 (where it enters the MS) and ground. It is in some ways similar to a zener diode, in that it conducts when the voltage across it rises above a certain threshold- approximately 22 volts in the case of this specific part.

Its purpose in this application is to protect the MS as a whole from overvoltage conditions on the main +12 line coming into the unit, such as might be caused by a glitch in the alternator's voltage regulation.

It will not, however, be in any way affected by the +12 supply coming into contact with the CPU. The presence or absence of the MOV does not affect the operation of the MS under "normal" conditions (when the +12 supply is not in an overvoltage condition). It does not conduct any current during normal operation, and is not in-line with the power supply.

Gryff

iTrader: (6)

based on what Joe P. said, no. the car was not running, and the battery was pulling 11.8v at the time.

Gryff

iTrader: (6)

Alright. Its dead Jim.

Everything on the mainboard checked out fine, I did have two questions about this though, a few components showed lower voltage. my voltage at the battery during testing was 11.8v
u5 was 10.5v
s12c was 10.9v
and d9 was 10.9v

Does this say anything or is the cpu dead?

After this I tried to load firmware, no dice.

Any thoughts before I throw stock ecu back in?

Joe Perez

iTrader: (8)

It's close enough.

Those three points should, in theory, all read the same, though slight variations are normal due to resistance in the probe. They key point is that they're within U5's operational threshold, and close enough to (battery - forward drop across D10) to be believable.

The most important test would be whether you have +5 at any of the various places where we expect it to live (such as the +5 hole near the proto area or pins 1, 20, and 31 of the CPU socket), but given your description of what happened, I'm leaning heavily in the direction of the CPU just being toast.

Gryff

iTrader: (6)

yeah, they were all like 4.95. so plenty close enough. I was thinking it was toast, Just wanted to make sure that the 10v was not an issue.

Reverant

iTrader: (10)

This is a problem with the Freescale microcontrollers. Atmel AVRs for example have a 5.6V Zener diode on ALL their input/output pins. I've never managed to destroy one, I wish I could say that for the HC9S12

Braineack

iTrader: (62)

That's who i suggested to you.

IIRC I was charged around $90 shipped to have mine repaired--the second time.

Gryff

iTrader: (6)

How quick was the turnaround?

Braineack

iTrader: (62)

within a week IIRC. He's in VA Beach, so quick deliver times.

Gryff

iTrader: (6)

cool, I emailed him this morning. Still waiting on a response, but we will see what happens between him and a friend of mine that may possibly have a card I can use.

Gryff

iTrader: (6)

Slight update on this, Still havent heard from him. and My potential sources for daughtercards came up dry. So im going to go ahead and get the one I have fixed. The stock ecu is back in the car and almost running, just need to hook up the wb with nb signal, and set base timing.

Gryff

iTrader: (6)

Another update, It lives! My only issue is that the tach does not work now, not entirely sure what the issue is. The car was running cops at one point in time, so therefore it has the resistor in the diagnostic box. I pulled that out to see if it made a difference, still no tach.