onefstm

I am changing the chip on my 993 and have run into a bit of an issue. Currently, the chip in the car has the slot facing away from the closest edge of the board. However, the corresponding slot on the board socket is facing the edge of the board. So, in the current configuration the slots don't match up.

I installed the new chip the same way and the car would only idle. I've changed many other things on the car and am not sure if something else is the issue or if the chip installation is the problem.

Has anyone else run into the issue of the DME socket slot and chip slot not aligning? Everything that I read says that the slot on the chip and slot on the board should align. Is it possible that the current custom chip in the car was programed with the slot facing the wrong way? Please see the pictures below. The first picture is the chip installed in the car before I removed it.

Thanks!!

P-daddy

I installed a Steve Wong chip on my 964, and remembered the slots facing the same side. It's possible your current aftermarket chip was built differently. Have you tried reversing the new chip to its proper alignment?

onefstm

We are on the same train of thought. I am wondering if my current chip was programmed with the slot facing the opposite direction, if this is even possible. I'm hoping that someone with more knowledge can tell us if that could be done.

I'm reluctant to reverse the new chip until I get more info. Steve Wong's site says that the chip should be installed with the slot facing the same direction as the old chip and also that the slot on the socket should align. If installed in reverse, damage could occur.

Bill Verburg

Here's a pic of one of mine

P-daddy

Your new chip is already installed 180 degrees from how it's supposed to align (reason why car only idles?) so reversing it to its proper orientation makes sense to me. If any damage could occur, it would have happened already.
I could be wrong, but I thought these chips only install in one direction- the prongs don't match up. It was a long time ago that I did this so going by memory.

onefstm

Bill,

Do you remember if the slot on the chip and the slot on the socket board lined up? Your clip slot is facing the same direction as mine was in the original configuration.

Foxman

I recently installed a Steve Wong in my 964, and the prior FVD chip had an adapter board underneath that also needed to be removed. Looks to me like you may also have an adapter board lying atop of the base board. That square notch doesn't look right to me...

Steve Weiner-Rennsport Systems

These chips are 28 pin symmetrical units which means they can be installed facing either way.

The small notch in the chip MUST be aligned with the notch in the socket otherwise the engine will not start since the chip will not get any power.

Sometimes chip makers use encryption sockets to prevent IP theft, however I don't see one in these pictures. These are normally green.

Its very easy to bend the little pins when inserting it into the socket so I would carefully inspect everything to make sure all 28 pins are correctly seated.

That looks like one of Todd's chips (Protomotive) so you might give him a call if everything else checks out OK.

P-daddy

Foxman may be on to something. I just did a quick search and noticed all the chips with the notch facing away from #30 (your original orientation).

onefstm

Steve, the original chip was definitely installed with the notches not aligning. However, the notch did face the direction that the chips do in the other pictures that I have seen.

Have you recall seeing other 993 DME's with notch facing the edge of the board and number 30?

Also, is it possible that the original chip was programmed by TPC with the chip backwards in their programmer?

Thanks for all the input gentleman!
​​​

Ivan J

This sounds completely wrong to me. The socket could have been installed on the board with the notch pointing the wrong way. The socket is nothing more than a pass-thru, to connect the pins of the chip to the signal traces on the circuit board. The new chip MUST be installed with the location of the notch pointing in the same direction as the one that was removed.

If you plug it in backwards and apply power, there is a very good chance that the device will be destroyed.

As someone else mentioned, make sure that all of the pins are actually in the socket (assuming that you have it oriented correctly). One of the pins may have curled under the chip when it was inserted in the socket.

Good luck.

Ivan J

No, it not physically possible to program a chip with it plugged into the programmer backwards.

Lorenfb

????

Some '95 DME ECMs had the socket installed incorrectly in circuit board. If the EPROM chip
is installed incorrectly relative to the circuit board, the EPROM and the processor chip
could be damaged.

onefstm

It seems that my slot is installed incorrectly. With the new chip installed with the slot having the same direction as the old chip, it did start. The car would not rev and would then die. It seems that I have other problems not related to the chip. It least its a learning and there is now documentation on the incorrectly installed slot issue for some 95's.

nine9six

Reading down through these posts and taking into consideration the, "new from factory" quality issues Steve Weiner has mentioned a number of times; it doesn't seem all that far-fetched, that a chip socket may have been installed 180° out.

It would seem Loren has validated this point, and this is a rather significant non-conformance by Porsche!

If this is the case and the chip sockets are indeed asymmetric, it would seem all "chip slots" should face the same direction relative to the PCB (and not the socket slot), regardless of socket slot orientation!.