What is inside a Polaris Ficht EMM, computer/logic/ignition/injector driver board

[K447]

This is the companion to the EMM power board, documented over here.

This is the main 'brain' of the Ficht EMM. It contains a lot of electronics, densely layered onto both sides of the circuit board.

As with the power board, it is normally completely encapsulated within an annoyingly sticky and soft gel sealant. Extracting the board involves removing a bunch of screws, scraping and peeling most of the visible gel sealant away, then levering the board out of the metal casing without breaking anything.

Once all the sticky gel is cleaned off, it looks like this.
Note: Higher resolution images can be found here.

This is the 'top' side of the computer board, which is what you see when you first open the metal cover side of the EMM.

Along the back edge (opposite the big 40-pin EMM connector) are the components that need heavy cooling. Before disassembly these were screwed and clamped to the surface of water cooling manifold that runs through the core of the EMM. Once side of the cooling flow cools the power board, the other side of the integral water jacket cools these seven components arrayed along the edge of the main board.

Note the Orange rubber tube sticking up from the board. This is the inlet for atmospheric air pressure sensor, which breathes through a small hole in the EMM's metal cover plate.


This is the 'bottom' side of the EMM main board. This is where a lot of the 'power' electronics reside.


The infamous C89 capacitor;
10,000uF at 6.3 volts, 105C temperature rating
16mm diameter, 40mm body length, Axial leads
There is probably enough room for a replacement capacitor as large as 20mm x 50mm

Too bad it is buried on the bottom side of the main board. Makes it hard to get at for replacement


Close-up of the air pressure sensor. The actual sensor is on the bottom side of the main board.



Ficht EMM 40-pin connector. It is important that these pins be free of corrosion and undamaged.

Molded into the back is
DRC23-40P-N009
Deutsch I.P.D.
USA

[K447]

More photos.

[K447]

The yellow C43 capacitor was folded down flat in manufacture, I turned it upright to see the label and surrounding components.
0.68uF at 500 volts DC.


C38 100uF at 100 volts (electrolytic)
C7 68uF at 100 volts (electrolytic)





I flipped the orange vent tube out of the way to better show what is nearby on the board.

[Keddano]

Very interesting Doc..... So what's the verdict? Are they repairable by someone with the right knowledge? Or does it take DFI with fancy whiz bang test equiptment? I think I have a old P90 computer that looks close to that..

[K447]

Ficht EMM Repair Service recommendation

.... So what's the verdict? Are they repairable by someone with the right knowledge?

Or does it take DFI with fancy whiz bang test equiptment?

...

For many electronic 'SMD capable component level' repair technitions the information I am posting is enough to allow them to replace obviously failed individual components. That may be all that is needed in many cases.

Documenting an undamaged Ficht EMM allows people to compare with their own failed board, in particular to identify components which have become charred and have unreadable part numbers.


I do not know what equipment DFI has, or whether much of it is specialized.

DFI has the experience to (presumably) rapidly diagnose commonly recurring problems and indentify specific repair areas. I presume they can also identify and repair some types of failures which do not have visible indicators (nothing visibly burned, but the EMM is not working properly).

I would also expect DFI to have effective and efficient methods for extracting the boards and doing the actual repairs.


Update: DFI is no longer a recommended service for Ficht EMM repair.
Neither is the fellow who markets himself as Ficht EMM Repair.

Lakeside Tech is now the only service recommended for repairing Polaris Ficht EMM.

http://www.greenhulk.net/showthread.php?t=268057&p=2917494&viewfull=1#post2917494

[Canadian]

What parts usually fail when fuel pump Eli control does not work and what part is the fuel pump control spark?

[Failedmsx]

Just removed my emm from my ski. Have the boards almost out. Suspect the processor chip was overheated as the gel was separated from it and looked like cracked glass around it.
I did work as a repair tech for cisco systems so hopeing the soldering skills are still good enough for smt.

[K447]

Just removed my emm from my ski. Have the boards almost out.

Suspect the processor chip was overheated as the gel was separated from it and looked like cracked glass around it.

I did work as a repair tech for cisco systems so hoping the soldering skills are still good enough for smt.

The 'different looking' gel around the Hitachi processor perimiter is dielectric grease type material, which looks different from the other gel encapsulated areas of the board.

Component failure usually happens elsewhere, but it is possible for cracked solder joints to occur on some of those tiny solder pads. Fragile to repair without some prior experience with these thin chip wires.

[cagatay87]

The gel around the Hitachi processor often looks different from the other areas of the board. If the CPU was seriously overheated it would probably have failed completely, not repairable.

Component failure usually happens elsewhere, but it is possible for cracked solder joints to occur on some of those tiny solder pads. Fragile to repair without some prior experience with these thin chip wires.

mine has problem about injector or ignition timing,im sure its about ecu i tried with another.
I have electronic skills , which ics or components can cause this problem do you have any idea?
my ecu is not working when i resoldered mcu middle of the circuit it started to work but its not passing more than 6200 rpm and bad timig too.
what did u used for clear circuit ? i used thinner, its ok but not well as yours.
thx already bro

[bfarnam]

For many electronic 'SMD capable component level' repair technitions the information I am posting is enough to allow them to replace obviously failed individual components. That may be all that is needed in many cases.

Documenting an undamaged Ficht EMM allows people to compare with their own failed board, in particular to identify components which have become charred and have unreadable part numbers.


I do not know what equipment DFI has, or whether much of it is specialized.

DFI has the experience to (presumably) rapidly diagnose commonly recurring problems and indentify specific repair areas. I presume they can also identify and repair some types of failures which do not have visible indicators (nothing visibly burned, but the EMM is not working properly).

I would also expect DFI to have effective and efficient methods for extracting the boards and doing the actual repairs.


Tip: Copy off any data/photos/documents you think is still valuable, then get rid of that ancient P90 computer! Old computer gear is rarely useful, it just takes up space and wastes energy even thinking about it.

Hmmmm . . . can you please tell me what you used to remove the aliphatic polyurethane potting compound? Obviously you start with picking out the bigger chunks, but it looks like you used some sort of board wash.

[K447]

Hmmmm . . . can you please tell me what you used to remove the aliphatic polyurethane potting compound? Obviously you start with picking out the bigger chunks, but it looks like you used some sort of board wash.

Mechanical removal only. Toothbrush and dental picks for the final cleaning stages.

There apparently is a special solvent that will actually dissolve the gel, but I do not know what it is called or where to get it.

[HiPeRcO]

Hmmmm . . . can you please tell me what you used to remove the aliphatic polyurethane potting compound?

(Agreed, the potting is polyurethane based, not silicone based)

[bfarnam]

Well its not polyurethane as that is not removable. It is most likely aliphatic polyurethane potting compound. This does not set "hard" and remains a soft "gel" (shore Hardness less than 50 or 70) but is not silicon based as Sylgard is. Silicon based potting compounds do not crystallize or discolor over time and are generally very hard to remove and do not have the heat transfer properties that are desired in the Polaris EMM. They will just trap the heat on the board and heat soak the components.

[MacGyver1981]

Hey guys. Not sure if this is the place to post this? But I'm working on the emm in my 2000 genesis. Q30 looks like it has a diode soldered to it. I'm sure there are people on here the are way better at electronics than I am. I wasn't sure if the mosfet transistor should be replaced or if this was someone's way of bolstering it the circuit?

[HiPeRcO]

That is very strange. That diode is connected from drain to source, and if I see the polarity marking correctly it would simply be in parallel to the MOSFET body diode (and installed in the same polarity as the body diode, e.g. Anode to Source, Cathode to Drain). So it wouldn't seem to be doing anything...

Are there other signs of someone being in there and hacking around?

What are the symptoms of your EMM?