Date sent: Mon, 16 Jun 1997 14:46:22 -0500
Subject: J.C. installation
I found that the available instructions, including those from
Duane Collie, did not encompass all the types of DME units. The
problem is that earlier E36 DME's were constructed in a different
way, apparently the same as E30's. That is the components face
inward on the circuit board causing difficulty in getting to the
Chip to exchange it. I know that others have encountered the same
I have a 1992 E36 325i. Apparently, BMW/Bosch started
manufacturing E36 DME's using the same manufacturing process as
the E30. That is with the components facing inward on the two
circuit boards. The boards are a bitch to get apart. The people
on the Digest make it sound easy to change E36 Chips because
theirs is the later style with the components, including the Chip
facing outward and easily accessible to change.
After numerous attempts, I finally got instructions from a
fellow digester, Kim Lau. He got the instructions from Jim C.
himself. The instructions for getting the DME out of the
compartment on the firewall are the same. I think the E30s may
require access from behind the glovebox.
Author: Bob Roberts CROBERTS_at_ria-emh2.army.mil
I noticed in the digest that you have a
1992 325i with the J.C. Chip. Did you install it yourself? I have
a J.C. Chip to install in my 1992 325i, but have been unable to
gain access to the chip plug in. Apparently, I have to open up
the circuit boards but have been unable to do so. Do you know
Author: Kim Lau klau_at_bbn.com
I did install it myself, but I never did get both circuit boards
completely apart. After a frustrating night of trying to get the
boards apart. I sent Jim an email request, asking for directions
on how to do it, to his credit, he responded that very same day
:). So armed with his directions, (see below) I tried to separate
the boards again that night. I got about as far as I did the
night before, no matter what I tried I couldn't get the board
apart. I did get the boards apart enough to CAREFULLY stick a
screwdriver underneath the eprom to pry it loose. I then took the
new eprom with a pair of tweezers and placed it on top of the
socket, I CHECKED TWICE to make sure the pins were seated
properly on the socket then I GENTLY pressed on the eprom to seat
it. I checked the eprom again, to make sure that none of the pins
were bent under the eprom. I reassembled the DME, put it back in
the car, and started the car to make sure it worked. I know that,
that's not the way its suppose to go in, but it worked for me. I
hope this helps, let me know if you have any other questions.
Jim C's reply to my request
First the FRONT of the boards is where the connex. is... The
REAR is the opposite side .. where the ribbon cable hooks the
boards together ..
1. Pop the plastic risers apart at the REAR of the board ..
2.The connector is 3 rows .. the bottom 2 stay with the bottom
board, and the top row comes out with the TOP board ..
3. To separate .. make both tabs come inward with small
screwdrivers (the small plastic ones inside the connector at the
ends of the top row of pins). And now swivel the BACK end of the
board UP and wiggle the front out .. What holds it is a small
"line" of plastic that mates with a valley.. by lifting
the REAR of the boards as far as they will go, and wiggling it a
bit .. you can get it apart
Otherwise find an independent garage and have
them install it for you ..
End of J.C.'s Instructions
I found the instructions from Jim C. to work.
I might add that when
lifting the circuit board up, I used a very narrow flat tipped
screwdriver about 1/8 to 1/4 inch from one end to pry that corner
of the board and start it out of the valley referenced. Be
not to crack the board, once started it comes out easily. I did
break off a couple of plastic tabs which held the circuit board
at the back of the connector, i.e, where it pulls out and lifts
up. This does not affect > operation since the connector holds
the circuit board securely when it is in place. I can't imagine
how you got your chip in without getting the boards apart. I
could barely see inside mine, plus I had to remove the protective
shield covering the chip before I could switch the chips.
This was a learning
experience. I think I could do one easily now after seeing how
they come apart. But, I am going to be very careful about
anything I read on the digest in the future. It may not be as
easy (or even the same!) as people represent.
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