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[PhilStubbs]

I have an ecu that runs stock fine, but won't run off the chip. J1 cut or connected makes no difference.  I normally don't take in chipped ecu's cause I like to do them myself, too many shitty solder jobs out there. But, I ended up with this one. It has a Motorola 20 pin mc74hc374an chip in it, I have a kit here with a TI sn74hc373n. Are they the same thing just different p/n or should I swap this other one in?

I have reflowed every solder joint for the chipping and checked for any solder bridging pins. All seems well. Even tried bypassing the original trace to activate J1. No luck.

[92CXyD]

Have check every connection per : http://web.archive.org/web/20071111193127/http://www.pgmfi.org/twiki/bin/view/Library/CEL

and

http://web.archive.org/web/20071115021952/http://pgmfi.org/twiki/bin/view/Library/EcuChippingWirelist

I had a similar issue and followed the the wirelist and found it was a bent leg of the chip socket and was not making full contact.

Drove me nutz for about 2 days. 

[HiProfile]

I looked up sn74hc373n and sn74hc374n since I couldn't find a moto datasheet. Looks like the difference is the 374 uses a clock signal for input (CLK), while the normal chip uses a solid input (LE). So chances are it will be find if you swap out that small chip.

http://www.ti.com.cn/cn/lit/ds/symlink/sn74hc373.pdf

http://www.ti.com/lit/ds/symlink/sn74hc374.pdf

[PhilStubbs]

Cool, thanks. Now to figure out how to get it out. I can solder like a boss, but can't remove components to save my life.

[Tim]

dremel cut the legs off the chip, and then you can remove one leg at at time from the board.

That's what I did bfore I had a desolder station, otherwise I would pull a trace or generally fuck something up.

[PhilStubbs]

I don't know why I never thought of that. +1 intranets for you sir.

[HiProfile]

Dremel? It's usually plated copper. Tiny snips will save you lotsa time.


And I'm not sure why the title reminds me of...

[PhilStubbs]

Lol

I don't own a dremil, so I was most likely going to snip with something.

[Tim]

I've used snips, but two swipes from a dremel were faster. Especially when I replaced a bunch of ic7, 22 pins get old when the snips don't want to fit between the legs. Whatever gets it done.

[PhilStubbs]

One thing I'm curious about is, how or why would someone put this chip in if it doesn't work? Maybe someone bulk ordered the parts rather than getting kits and got the wrong thing?

[HiProfile]

"$.02 cheaper and the p/n is almost the same? Sure why not..."

or

"Fuuuuuuuuuu, they're on backorder? Well this p/n looks close enough."

etc

[PhilStubbs]

I hope that's all it is. Haven't had a chance to try swapping it yet. I really need this ecu working soon though

[PhilStubbs]

Well, swapped the chip and still the same thing. I'm lost. Ideas?

[HiProfile]

I'd check the chip socket to see if it gets power and ground. That hondata/pgmfi socket checker you linked to a while back may not be a bad idea.

[PhilStubbs]

I have a demon I put in, it lights up when I put power/ground to a25/b2, but it blinks and it should be solid. I posted on the hrtuning forum and they say that what it does when j1 is not making a connection. I have been all over J1 and even run wires to bypass it. No luck