August 21st, 2023, 1:51
August 21st, 2023, 3:36
August 21st, 2023, 3:40
Lardman wrote:My guess would be back of the pcb nearest the gpio. I'd pull 1 nand and retest to see if anything else disappears. Until you've had responses from the chips previously you can't be 100% it's not just dead.
August 21st, 2023, 3:49
August 21st, 2023, 6:08
August 21st, 2023, 6:34
August 21st, 2023, 7:22
Lardman wrote:You can either wait for someone who has direct experience of pulling nand form a c300 or you can find out by experimenting. The chip you have labelled 0 is where I'd start.
If you remove nand you have marked 0 or 1 and recheck it will give you an idea of the channel layout.
August 21st, 2023, 7:48
August 21st, 2023, 22:26
Lardman wrote:Perhaps this will help, Channels =/= chips.
https://www.cactus-tech.com/resources/b ... and-banks/
August 21st, 2023, 22:50
August 21st, 2023, 23:40
fzabkar wrote:Show us a photo of the unpopulated PCB.
I would locate the Ready/Busy* pins of each IC. I expect that each pin will be connected to a pullup resistor. If so, then you can safely short this pin to ground (because it is open drain) while using PC3000 to scan for IDs. This should tell you which chip(s) is/are associated with a particular channel.
August 21st, 2023, 23:44
August 22nd, 2023, 0:32
August 22nd, 2023, 1:40
fzabkar wrote:This is my guess for the Ready/Busy* logic.
I would confirm that the 1.8V end of the resistor is indeed at 1.8V. You could do this on the unpopulated PCB. There is also a 1.8V test point which you could use for this purpose.
Also confirm that the other end of the resistor (X) is indeed connected to the NAND's R/B* pin (continuity test on multimeter).
If all is OK, you can then short point X to ground during the ID check in PC3000. I expect that the corresponding channel will fail to ID, in which case this method should narrow down your candidates to 2.
August 22nd, 2023, 1:52
August 22nd, 2023, 3:00
fzabkar wrote:1. Check continuity on either donor or patient while powered off. It's probably better to do this on the 200 ohms range of your meter.
2. Ground is any screw hole. You can make a tiny probe with one end wired to ground and the other end wired to a sharp pointer. Then you can touch the pointer to point X while you are running your PC3000 ID check. Tweezers would be too big and risky.
August 22nd, 2023, 3:02
August 22nd, 2023, 3:31
August 22nd, 2023, 3:41
August 22nd, 2023, 11:21
fzabkar wrote:Sorry, I don't think I can help you.
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