KT2 Exposed

[qqqqqqqqqqqz]

OK, so I tested S502.

It works exactly the same way as the actual power button, i.e., pressing it briefly asks me for my PIN, holding it for 30-40 seconds reboots, etc.

So... not what you were expecting, I guess?

I haven't yet tested S501, reset. Mostly because I'm not well equipped. (A ⅛th-inch flathead screwdriver tip doesn't do well!)

[knc1]

Originally Posted by qqqqqqqqqqqz

OK, so I tested S502.

It works exactly the same way as the actual power button, i.e., pressing it briefly asks me for my PIN, holding it for 30-40 seconds reboots, etc.

So... not what you were expecting, I guess?

I haven't yet tested S501, reset. Mostly because I'm not well equipped. (A ⅛th-inch flathead screwdriver tip doesn't do well!)

Thanks.

What device?
This is a PW2 your checking?

- - - -

I was guessing at the shadows of buried inter-connect layers using someone else's posted photograph. I don't have a PW-2 of my own.
Much better that someone actually try it.

Yes - tiny contact points - takes a very steady hand and sharp eyes (something us 70+ lack).

[qqqqqqqqqqqz]

Originally Posted by knc1

Thanks.

What device?
This is a PW2 your checking?

Yes, that's correct.

[knc1]

Double thanks.

[knc1]

Is there life in this old thread of mine?
I hope so, the KT2 is still disassembled, waiting for me to get on with this exposure.

On the subject of exposure, perhaps no more jury-rigged digital camera for close-ups.
Instead, (I admit it, a low cost) digital microscope.

Sample attached.

Picture is of two 'standard' SMD pad layouts.
Using Gimp, or your other favorite image tool, you can count the pixels/mm in this view.

I come up with .033mm per pixel or 33 microns per pixel (vertical).
If the smallest detail of interest is 0.1mm, then this gives 3 pixels for that detail.
The smallest (common) trace width is 6mill (.006 inch), which is about 5 pixels in this sample.

This should be sufficient for PCB close-ups.
(And its a lot easier to use than my jury-rigged digital camera.)
- - - -
Edit:
Next picture, the serial port pads on a K4S (because someone recently posted that a K4 didn't have a serial port).
This **is** a close-up, works out to 72 pixels/mm.
- - - -
Edit:
Next picture, the KT2

[knc1]

The final bits and pieces needed to bring my PCB creation skills a half-century closer to current practice should all arrive before week's end.

- - - - -

Plan A to deal with these nearly microscopic contact points:

On a small piece of Pyralux (that brown stuff flat flex circuits are built on) layout five thru-hole pads that match the solder bumps in the serial port pad.

Bring the three signal lines (Tx, Rx, Gnd) out to humanly visible sized solder tabs.

Optionally, provide the three wires already soldered to this Pyralux adapter.

- - - - -

Now the user (assuming soldering skills challenged users here) -
Aligns Pyralux adapter so the five solder points are centered in the five holes -
Optionally, fastens little bit of flex in-place with a drop of super-glue on the backside -
Then using solder paste with hot air OR hair-sized solder and tiny iron tip; connects the dots with the exposed flex copper in all five places.

Then a few drops of glue on the wires to the board to provide some strain relief -
the highly skilled soldering part of the job will be done.

The backing material of Pyralux is Kapton - it will provide some protection from doing any board damage during the very brief soldering experience. (I hope.)

It will still be possible to accidentally de-solder those two resistors - so the user will still need to be careful - but I expect this adapter will decrease the overall skill level required.

(Presuming I can make these tiny little adapter pieces.)

[geekmaster]

Fascinating. I am interested in this.

[knc1]

Originally Posted by geekmaster

Fascinating. I am interested in this.

Since the only known way to jail break the 5.6.x series firmware is by using the serial port - -
I think a lot of people will be interested, **IF** I can make the connection process simpler.

A big **IF** - -
Counterfeiting postage stamps would be easier.

You have probably read by now that Amazon is pushing out OTA updates for the PW-1 and PW-2 to also lock the older models down.
https://www.mobileread.com/forums/sho...d.php?t=262279

[knc1]

In post:
https://www.mobileread.com/forums/sho...3&postcount=50
is attached pictures of the PCB pad layout used on the K4 and KT2

Attached here is the Data Sheet on the matching Molex connector.
(I didn't find it, twobob located this matching connector.)

On page two is a drawing of the recommended pad layout for the connector.
Step one in making a matching Pyralux overlay is to verify that Amazon/Lab126 is using the recommended pad layout.
If not, then determining what dimensions they are using.

[knc1]

Obsolete.

[knc1]

Obsolete.

[knc1]

Obsolete.

[knc1]

I would probably be wise to start with something relatively simple.

This old thread of mine, the slip-in serial port connector for the K3 seems pretty simple:
https://www.mobileread.com/forums/sho...06&postcount=1

Especially since I now have all of the proper materials (including what was, 3 years ago, an unusual thickness PCB strock).

A bit on the small side, but nowhere near as funky as this Pyralux overlay I intend to make for the newer models.

[knc1]

Originally Posted by knc1

I deleted the original content of this post.
After some study, and a few dozen timed trials, a faster etch is very possible.

I'll fill in the details here after a few more confirmation runs.

Phooy - running out of 35% hydrogen peroxide for the test runs.

Well, I do have 10 days worth of notes to type up and make sense of (before the acid splashes do in the paper and ink).

Want to etch a board in under 20 seconds?
When reference board in MG-415 commercial etchant takes 20 minutes?

The 'key' this time was to use a buffer (C2H4O2) rather than a chelating agent (C6H8O2).

[knc1]

Obsolete.