Brian,

I would not jump to the conclusion that this was a Nokia induced defect.

The photograph shows a scratch from what might have been a screwdriver. The damage could have been caused by someone slipping while opening the N800.

I'm not implicating our owner, Xandor...this damage could have been done before he bought it. Xandor did state he has had trouble with it "for a while".

The photo shows mechanical forces were at work here tearing those components off the substrate.

It would not surprise me that some N800 NITs sold on eBay are victims of this type of damage. Big box stores like Best Buy, etc. are supposed to send customer returns to their source, but sometimes they sell them to customers instead, which is why I always insist on looking at an item at retail for signs that it might have been a customer return. I had this experience at a Walmart & a Target store both on the same day when I was looking for a GPS. Both stores tried to sell me items as if they were new but which I determined had been customer returns.

It is most possible that this unit was not a defective device shipped by Nokia but rather one damaged in the field by someone else. The scratch has me thinking it was caused when opened carelessly. Once again, I am not implicating Xandor, but it appears to me that someone slipped with a screwdriver while trying to open this NIT and did the damage.

M5

Yes, I think that holding Nokia responsible for this after an expired warranty would be pushing things. So my question still stands: does anybody have any idea what would be required (for me) to repair this? What (value of) chips am I missing?

thanks,

xandor

The bad news is, the pc board looks damaged, so it isn't as easy as replacing those missing discrete components. There are a couple "pads" (some people call them "lands") that appear from your photo to be torn away. The board is a multi layer board (more than 2 layers, meaning there is stuff in the middle that is inaccessible). It might be possible to use a conductive epoxy, but that is not a guarantee. Furthermore, as you know, the type of component (R,C, or L) that is missing and it's value in ohms, nanofarads or microhenries, has to be known.

Maybe you can find an N800 with a cracked screen, which has a good motherboard as a parts donor to fix yours. Check eBay.

Maybe Thoughtfix has an idea what components are missing on your unit and their values.

~~~~~~~~

The OP has a unit that doesn't appear to have any PCB damage. He just needs to resolder his USB connector back in place. Xandor's unit is far worst off.

Sorry.

Wow, yeah, I had noticed the damaged pads on that one item, but was thinking that there is still enough copper for the solder to stick to. As for the layers, do you mean that there are actually components sandwiched in the middle of the board somehow?! That would make it very scary to attempt any sort of soldering!

As I say, I'm in the middle of Mexico, which makes getting stuff from Ebay and the like a bit...complicated.

And I'm not the original owner of this tablet, though it appeared to be in good condition when I got it, and performed fine for many months. Odd...

(and, yes, I had pm'ed ThoughtFix. I'm hoping now that he might have access to schematics...)

Thanks a lot for your input!

Value of the missing components is so low that you can't even measure it

But because pads are torn off, it is very hard to fix it

Oh, you mean because they're so teeny-tiny?

Meanwhile, I did find a pdf of the schematics, and it appears that these components are, indeed, part of the touchscreen circuit, either caps to ground, or resistors in series with the sig path. Unfortunately, the PDF isn't quite clear enough to be able to determine precisely which components I'm missing.

Here, in case you're curious, I've just uploaded a copy to my server which you can find here. It's actually pretty interesting to look at, being several pages long including a photo of the nekkid board!

Meanwhile, as I write this, the entire school age population of my town is marching by my door, drumming and blowing bugles, this being Mexico's independence day.

Viva!!

Well, I'm still determined to see if I can't at least effect some kind of kludge (yes, I am that stubborn). I might be able to just bypass the damaged pads if I can just figure out what components go there; just need a couple of leetle caps and resistors to fix this $300 baby, and judging from the schematics nothing connects through to the other board side. I now see that my posting of a link to schematics is redundant since there is already a thread (scroll down!) on it. Problem is that this PDF, which seems to be scattered throughout the web, isn't sharp enough to see details, such as the components I'm concerned with (F3 on the "Component finders" page).
Is there anybody reading this who might happen to have a hard copy and who would be kind enough to share with me which they are? Also, I think some of the resistors are labeled with the value "10R"--what does that signify?

Thanks much for all your input!

xandor --

These components seem to be tied to the X1501 connector, so the section of the schematic in question would be on page 3 of the schematic you linked to...

The next question is to determine what pins on that connector are (supposed to be) electrically connected to the missing parts on your circuit board. It's hard to tell from your photo what pin numbers those might be... it's a 50-pin connector, but I'm not sure where the pin numbering starts. Usually it starts in the upper left and proceeds clockwise. This would indicate that the components in question are connected to pins 26 & 27, which are the X- and Y- pins for the touchscreen. These pins are connected to resistors 1510-1513, all of which are 1% 10-ohm resistors (probably 1/4 watt, based on the size... 1/2 watt at the most), labelled on the schematic as 10R, to resistors 1514 & 1515, both 1% or 5% 1 megohm resistors, a zener diode pack (1520, the square component) and to capacitors 1509-1514, all of which are 10 nF (nanofarad) capacitors.

... it'd help to see a high-resolution picture of that entire connector on your circuit board, especially if there's any markings to indicate pin 1 and/or pin 50 .... that'd help narrow it down. Once we've determined that, for sure, we can follow the schematic and the foil pads on the circuit board to determine which components are missing and what their values are....

Briand,
Yes, what you say is correct, although I'm not sure why you are focusing on X- Y- (26,7) at the expense of X+,Y+(24,25). And, naturally, these 4 pins are bordered on BOTH sides by a ground pin...
I've tried doing a bit of tracing, including on that connector, but I think I'm getting false continuity signals due to caps getting charged, if that makes any sense.
That connector does NOT have any markings ID'ing the numbering.
Again, I was hoping to ID the parts via somebody who has access to a hard copy with a clear map on the final page, which would just show everything. I can ALMOST make out the IDs on it but not quite...! (again, F3, maybe also E3, on the grid). I THINK it's two resistors sandwiched by two caps on my damaged row--pretty sure I can discern the C's and R's but not the numbering.
I must say, though, that just after I made that last posting, I noticed that the OTHER side (right-hand on the schem) of those resistors and caps connect to 4 touch terminals on the OMAP chip, so there probably is indeed a pass-through to the other side of the board (even though this would seem to be underneath the headphone jack!), and this might make my task, given the state of the pads as others have accurately commented upon, nearly impossible (my goodness, am I admitting that? No...).
But MAYBE I'm lucky and the three items I'm missing are NOT at the points that pass through (but how to tell...hmmm...).

Meanwhile I'm just happily obsessing along...
The tablet IS useful for listening to BBC (and not much else) in its present state, though (assuming it still is the same as before this last disassembly).
And, hey, thanks a lot for clarifying the values on those "10R" resistors, etc.! Really appreciate your interest in such an obscure topic!

If the parts are the same in the N810, I can slip you a copy of the N810 schematics (the N810 ones is in perfect quality)