GENERAL Unable to read NAND on E79 board

[webnomix]

Hi, I have a Jtaged Zephyr board that was given to me with E79.

Tried to read the Nand, but the nand-x was not found. Followed MartinC's excellent guide and, sure enough I am getting very low voltages on pins 1 and 3

1) 0.11v
2) 3.29v
3) 0.10v
4) 0.00v 41.9ohm

So I have reflowed the Southbridge but no change. The only thing I can think of so far is that it was a Auld Clamp install and there is evidence of resoldering around all points on mosfet Q2N1 and Q3M1.

All wires were removed and there is no obvious damage to traces etc.

Worth another go at a reflow (have never reballled southbridge :-() or could it be one of the mosfets?

Console will boot to E79.

Thanks for any advice, cheers.

 

[Martin C]

Yep, points 1 and 3 go directly to the southbridge.

Try soldering the points to the underside of the board - it's possible the signal's not getting through the headerpin holes properly. The traces for both points are on the underside too.

 

[webnomix]

Cheers Martin, will do.

 

[webnomix]

Have wired up to the underside and now get the following.


J-Runner v0.2 Beta (276) Started

Checking Files
Finished Checking Files
Version: 03
Flash Config: 0xFFFFFFFF
Unknown Flash Config found.
This may due to a new console type, bad soldering or hardware failure.
If it isnt the first check your soldering and reset your device.
You can always press ESC to cancel the read.
Error: FFF reading block 0
Error: FFF reading block 1
Error: FFF reading block 2
Error: FFF reading block 3

At which point I esc.

Should also mention that I have reflashed my nand-x prior to the reflow (as part of the testing process) and it gave me no errors.

 

[Martin C]

Can you post images of your soldering?

 

[webnomix]

OK, here are the pictures. My apologies (and not just for photo quality) but as you can see, the colour of the breadboard cable extensions does not match the cable colours, but hopefully the long shot shows the correct cable colour placement.

 

[Martin C]

If all traces are intact then it may be the southbridge which is the problem.

Have you tried wiring up the JTAG points, as E79 is normally due to a JTAG image not being able to boot? You might need to try all three permutations.

 

[webnomix]

Yep, all traces look good. I have reflowed the Southbridge, but have not redone the Jtag wiring. I realise this would cause E79, but do you think it would also stop me from reading the nand? Easy fix if thats the case

 

[Martin C]

You might need to replace the southbridge in this case - I think that's more the issue. The reason I suggested wiring up the JTAG stuff was you can reflash the original NAND back using XeLL

 

[webnomix]

You might need to replace the southbridge in this case - I think that's more the issue. The reason I suggested wiring up the JTAG stuff was you can reflash the original NAND back using XeLL

Yep, was worried about that - though that might be my next thing, but didnt fancy it. Was hoping it might be something to do with the mosfets (but I hate replacing those as well, think I prefer working on the SB).

 

[Martin C]

It's not the mosfets. The only two readings which look off are 1 and 3. They go to the SPI portion of the Southbridge.

You can also use a NAND read/writer to do the job.

 

[webnomix]

It's not the mosfets. The only two readings which look off are 1 and 3. They go to the SPI portion of the Southbridge.

You can also use a NAND read/writer to do the job.

Thanks, for that. Just finished off rewiring the Aud Clamp and I can now read and write to the Nand, so thanks for your assistance, it does look like a combination of all three. Now I can get to the nand the E79 should be the easy part.

 

[Martin C]

Wondering if the transistor used for AUD_CLAMP was the culprit, especially if it had been detached through a previous attempt? Either way, glad it's working now.