Reading/ Reflashing 29F chips - electrical gurus?

[pocket-rocket]

I was on the same page as pocket-rocket. I also saw U-tube videos of lots of people soldering/modifying X-box chips. They make it look too easy! But then I began to think of the reliability factor - the x-box doesn't see potholes which could break weak solder welds.

No, but I bet they have thinner, weaker boards to mount to, they use junk lead free solder that sucks (it's not even the right kind to use in this sort of application) and they produce lots of heat in that little box. My Xbox sitting on the entertainment center shelf beside my VCR would actually get warm enough through the Xbox case to get the shelf really warm on the bottom side- through 1/2 particle board. Lead free solder tends to crack with the heat up and cool down cycles an Xbox sees leading to the RRoD which is why people that do long term fixes either a. reflow it, or b. reball the BGA GPU. I'm not trying to be mean, but if you make weak solder connections, you shouldn't be thinking of modifying a PCM. As long as you have good solder connections with the right solder and have things secured well enough not to fatigue, you shouldn't have to worry about pot holes, really.

What about soldering leads to those solder pads and running them to some sort of header or connector that mounted to the case? Then you can close up and seal the PCM again and just plug a cable into the header or connector when you need to reprogram?

[chri0029]

I just thought I would close this tread since I opened it. I don't want to leave it too open-ended for anyone looking.

I talked with an electronics professor about how to directly read/ reflash the chip. In a nutshell, he said I could go the long and cheap way which involves making a chain to a PC involving a USB to RS232 (serial port) converter to an 8 or 16 bit addressing interface chip to my PCM chip and a simple C program. I could directly attach a 44 pin test clip (~$40) directly to the chip in the board (since all address pins must be used for reprogramming), but he wasn't sure how the other wired components would interact as power was added to my chip for reprogram. So the safest solution would be to remove my chip from the board and resolder (either a DIP to the board or harness for external chip work). Or I could go the easiest and more expensive way of purchasing the electrical daisy chain above already incorporated into a Willem programmer (incl software) which could be found on Ebay and a PSOP44 Socket adaptor for my 29F chip. All said-and-done, about $150 including the PCM from the junk yard and some really good/careful soldering skills. That includes some inherent risk of damaging the board from a less-than-perfect chip removing or a weak solder job.

The positives: I could reprogram my PCM & BCM chip for a low price, plus any future IC chip I could desolder (Xbox, FTA, etc). The negatives: the tiny particular soldering, risk of board damage, future reliability, and the fact that every vehicle I want to reprogram would probably involve soldering.

Then would come the bin editing (and masking). A whole different story ...

Maybe HPT doesn't look so bad after-all. But I want to first explore the other treads of reflashing through the ALDL. Since I can get the seed/key, I should be able to upload custom bins with a tech2 and software. Let's see where this goes (as read on other treads), then possibly come back to the hardware side of things as Dimented24x7 found it easiest to do years ago.

[robertisaar]

but he wasn't sure how the other wired components would interact as power was added to my chip for reprogram.

i believe brad attempted, or at least mentioned this and stopped because of that exact reason...

OBD1.5 anyway.

[beyerch]

Chip Repair on board

Not to add a monkey wrench to this discussion; however, I know 100% that there is a 'repair' tool used internally that just clips onto the flash chip; therefore, I do not believe power being distributed on the board is an issue....

FWIW.

Additionally, I've removed/resoldered well over 100 28f400's and put them back in vehicles without any long term issues that I know of. If you'd rather remove the memory chip, get a decent iron, practice, and you'll be fine.