FICM Dissection. (Possibly a repost?)

[Aaron]

I took one of these apart just to see what the fuck makes 'em tick. (Pardon the 'Tick' pun)

 

 

Smelled like 'electrical burnt' inside - thats the best I can describe it. This one was putting out around 27v KOER if I recall rightly.

 

Retail, too.

 

I would assume the black deals on the right side of the photo are the step-up transformers to roll the B+ up to 48v.

 

 

 

 

[LARRY BRUDZYNSKI]

Do they look like repairable boards or are they silicone sealed?

[Aaron]

The board is silicone sealed in some spots, but I bet you could change those inverter/transformers instead of the whole FICM.

 

Fuck...shouldn't have said that....

 

AFIAIC - there's too much liability in changing those, only need one guy to get zapped. There's some pretty big capacitors in that step-up side.

[GregH]

You're right - the right side of the picture is the step up portion, and that's the part that usually fails. It will unbolt from the case, and as you see it unplugs from the main board.

 

Risk of shock is pretty low; 48V is less than the voltage on a telephone line. On a hot day, with really sweaty hands, the risk of shock is a little higher, but still not likely.

 

I would imagine that a jig specially made to handle the unit will be a special service tool, or a discharge tool that connects to the failed board or the capacitors directly.

 

And I am quite surprised that we aren't rebuilding these units yet...

[Brad Clayton]

Quote:

And I am quite surprised that we aren't rebuilding these units yet...

We haven't been deemed smart enough yet, by the BIG MACHINE .

[Keith Browning]

We haven't been deemed smart enough yet, by the BIG MACHINE .

I resent that sentiment! Only ONE of my knuckles actually hits the ground!

 

[Aaron]

Yeah, but that's the problem, Keith - that one knuckle will provide a clean path to ground for your shock when you hit the FICM output screws

[Aaron]

it unplugs from the main board.

 

 

It actually doesn't 'unplug'. The little cover on the FICM, once you take it off, there's four screws that connect both boards together. I nearly broke it before I realized this. LOL

 

Figgered it out without breakin' it, and it's good to go.

[Bruce Amacker]

I took one apart a while back, too. It was an '04 no-start P0611 IIRC and I couldn't find any physical damage to it. My guess is the small board with the big caps and coils is what failed. I think IH ships the same PN for 6 and 8 cyls as a replacement part and a different PN for 6 cyls from the factory. That means if you install a new IDM (FICM) on an DTEGR it has 8 caps and coils and only 6 are used. Physically they are identical externally, but I haven't disassembled one to verify this.

 

Small board:

 

 

Big board:

 

 

[Aaron]

Dammit! I thought I had one up on you, and took something apart first! LOL

 

I figured you'd already had one apart. Mine didn't look damaged either, just stunk like a burned out TV or radio, you know, something that's had a smoke leak?