Hello! Has anyone out here worked on any NT8E02 cards? Vintages CE and DE? If so, I would like to know if you're having the same problems I'm currently having.
On these cards, there is a 'gold box' (p/n: NT8E028
that has two Xicor chips on it, one on the top and one on the bottom of the 'box.' And, these chips typically are what's bad when the card has failures. So, that's ok right? Just get more Xicor chips to replace them. WRONG. I've been working with these cards for almost two years now and when I first started, we purchased some replacement Xicor chips and they worked perfectly fine. Then, we ran out and needed some more, so ordered them, and they didn't work. And we have yet to find any more that work since then. I've tried about 20 different vendors, date codes, etc. And none of them have worked.
And it gets even more interesting!
I tried putting a Known good chip onto one that had a bad one, to try and repair it, and it didn't work.
I sent two chips, exact same date codes, one that was good and one that was bad, to Intersil who took over Xicor, for them to test, and they found no difference.
Sometimes, I can fix the chip by doing my own wiring of the leads, but that only works like 1 in 100 times.
I was told that these chips have been known to not duplicate the programming correctly, but, why then, would a known good chip still not work? Seems like it's something in the board itself, not just the chip.
The chips are in positions U7 on the top and U28 on the bottom. U7 is more frequently bad than U28. And for U7 it is ALWAYS ALWAYS pins 1, 2, and 3, and 17, 18 and 19 that go bad. ALWAYS. Pins 1 and 19 are the wiper outlets and pins 2, 3, 17 and 18 are the terminal connectors. I have Yet to see another U7 that is bad but these pins are good.
I contacted Intersil directly and they said to check the signals between two of the pins on a good chip to a bad one, one's having to do with timing. They thought it could be a timing thing? So, I did that, checked the pins, and they were Exactly the same. At 3 different HZ levels. So, there goes that idea...
I've also tried taking off the pads for those pins and re-wiring it myself because the pads don't seem to be conducting right, but that didn't work either.
It says in the datasheets that to run in 'Normal' or 'Cascade' Mode, you have to externally connect the terminal connectors to the wiper pin. That would be pins 2 and 3 to 1, and pins 17 and 18 to 19. So, I did that, and that makes those pins have signals again, but not the 'correct' signals.
So, I have no idea what's going on with this. Just wondering if anyone else has had this problem or knows why it's happening? Is it the board, the chip, the leads? I have no clue.
If anyone thinks they can give me some help, any information would be great! THANK YOU!!!
