PW3 I plug my kindle serial to adapter, nothing shows up.

[SupremeJerk999]

I got myself a USB to TTL adapter from prolific

Set the baud rate to 115200, followed everything on here, plugged the adapter's tx to kindle's rx, rx to dx, it's grounded and working. All set.
When I turn the kindle on, nothing shows up on terminal. I tried both windows and linux. Sometimes a few gibberish characters show up, but that's it. Sometimes the kindle's screen changes to "recovery mode" instead of the boy under tree, but I still can't access anything,

No luck, this paperwhite is dead, only to bring it back is via the serial port, but it's a problem if I can't even connect.
Any ideas?

[eddie.t.h]

Is your adapter 3.3v or 5v?
Check by shorting together tx and rx. Then, typing something on the keyboard in putty, you should see the characters being typed.

[SupremeJerk999]

Originally Posted by eddie.t.h

Is your adapter 3.3v or 5v?
Check by shorting together tx and rx. Then, typing something on the keyboard in putty, you should see the characters being typed.

That test works here, I could see all of my inputs in the terminal when rx and tx were shorted.

Additional info:
the adapter has both a 3.3v and a 5v pin, but I didn't hook either to the kindle because the tutorial says it needs to be 1.8v. Another person told me the other day that you only hook VCC to unpowered boards, so I took that advice, fearing I might fry the kindle.

Thanks.

[eddie.t.h]

Yes, vcc is not to be connected. If the converter is operational, the only option is a bad connection. Check GND carefully, try swapping tx and rx places.
Look carefully under the magnifying glass if you have damaged paths on the pcb. They are very delicate.

[SupremeJerk999]

Originally Posted by eddie.t.h

Yes, vcc is not to be connected. If the converter is operational, the only option is a bad connection. Check GND carefully, try swapping tx and rx places.
Look carefully under the magnifying glass if you have damaged paths on the pcb. They are very delicate.

Yeah, apparently this kindle is fucked up somehow. rx and tx switched, still not signal.

There's no reason for the PCB to be dead. It was never anyone else's kindle and I am the first to tear it down.

I have not soldered anything though, I'm using the pin needles as people here recommended. Idk, but after getting it done, I don't think anyone in their right mind would say it is easier to put those pin needles there. These testpoints on the kindle board are the smallest testpoints I've ever seen, and getting pin needles to stay there is extremely fucking hard to even get them there.
It would've been way, way way much easier to solder those onto the board. I wish I had done that instead.

Anyways, I think this kindle is dead for good.

[eddie.t.h]

I have repaired dozens, if not hundreds of Kindles and have not encountered one with a defective serial port. If the reader gives any signs of life then there must be something on the port.
If you have the opportunity then solder the cables and do not use needles. Only secure the wires with kapton tape because it is very easy to tear the tracks from the pcb.

[SupremeJerk999]

Originally Posted by eddie.t.h

I have repaired dozens, if not hundreds of Kindles and have not encountered one with a defective serial port. If the reader gives any signs of life then there must be something on the port.
If you have the opportunity then solder the cables and do not use needles. Only secure the wires with kapton tape because it is very easy to tear the tracks from the pcb.

Ok, it seems like I scratched the tiny track above the Tx terminal in the Kindle's PCB.

I'm not sure if that's the cause, but here's what's happening, I managed to get the kindle to connect and regularly give me info back via serial, but it spits out gibberish


Baudrate is 115200, as expected.
I also tested the USB adapter with another device and it works fine.

[SupremeJerk999]

Originally Posted by SupremeJerk999

Ok, it seems like I scratched the tiny track above the Tx terminal in the Kindle's PCB.

I'm not sure if that's the cause, but here's what's happening, I managed to get the kindle to connect and regularly give me info back via serial, but it spits out gibberish


Baudrate is 115200, as expected.
I also tested the USB adapter with another device and it works fine.

Another thing worth noticing: the USB cable didn't work as a common ground. I didn't get any signal at all until I connected the adapter's GND to some ground point in the Kindle itself.

[eddie.t.h]

Such garbage on the console indicates a connection problem. Simply the cable hangs in the air and acts as an antenna. The USB ground is the ground of the Kindle.

[SupremeJerk999]

Originally Posted by eddie.t.h

Such garbage on the console indicates a connection problem. Simply the cable hangs in the air and acts as an antenna. The USB ground is the ground of the Kindle.

I redid all the connections (now with solder), now I have solid contact between the pad and the serial cable, still getting garbage, but now it's much more and in a much faster rate.

I think it's not acting as an antenna because the output comes in bursts right after I turn the kindle on, just like it's expected when you turn a serial device on.



Also, after the kindle has been turned on for a while, the same gibberish data comes at regular intervals.

So now I am sure I have a connection, it puts out a lot info right when it boots, then it slows down and gives me slower pulses of data, just as expected, but all is gibberish.

Here are my Putty settings:

My serial device driver configs:

I'll try on Linux again now that I redid the connections, let's see.

[eddie.t.h]

It looks very strange. Do you run Kindle from a battery or a usb? It looks like some terrible interference on the data transmission lines. Perhaps your interface does not support 3.3v...

[SupremeJerk999]

Originally Posted by eddie.t.h

It looks very strange. Do you run Kindle from a battery or a usb? It looks like some terrible interference on the data transmission lines. Perhaps your interface does not support 3.3v...

Battery and adapter are fine. After we talked earlier today, it started to bootloop, an issue it never had before. I just took the battery and the eInk screen and threw the rest away, this Kindle is dead for good.

[hanakomisa]

If it is a red board, mini USB connected FT232RL adapter (looks like this), you need a 1.8v regulator such as an AMS1117 1.8 to tune down the 3.3v signal to 1.8, you connect the right leg of AMS1117 to 3.3v, then the middle leg to VCC of the serial adapter's board. Left leg is to connect it to ground.

Once that's done, you'll have a 1.8v signal for RX/TX, and only then you connect those to the Kindle. It might be a little too late for your PW3 though assuming you sent 3.3v signal through it, possibly killing the serial interface.

[eddie.t.h]

Originally Posted by hanakomisa

It might be a little too late for your PW3 though assuming you sent 3.3v signal through it, possibly killing the serial interface.

Kindle serial interfaces (on i.MX6 and older processors) are designed to work at 3.3v.

[hanakomisa]

Originally Posted by eddie.t.h

Kindle serial interfaces (on i.MX6 and older processors) are designed to work at 3.3v.

Huh, you're right. I just checked the datasheet for the i.MX6SL. I wonder what the whole "use 1.8 or you'll break your serial interface" schtick came from then.