This evening I was doing some work at school, and I noticed that they were throwing out an HP TC1100 Tablet PC, one of the computers I considered getting but instead ended up with a Toshiba m205. I of course grabbed it, although a tech warned me that it had graphics issues. I brought it home, found it some RAM, plugged in my current HP's 18.5V, 3.5A, positive-tip power supply, and it did indeed have graphics glitches. I disassembled it, nothing obviously broken, put it back together, same thing. This time, I did a full and complete disassembly, with the help of the service manual:

http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c00681631/c00681631.pdf

I now have the motherboard laid completely bare, including the heatsink/fan combo, all of the tape and labels (as well as I could peel them off), and every cable and wire. The plastic PCMCIA bracket, RAM slots, and ports are still there, as are the soldered-on chipset, graphics coprocessor, and processor. Tomorrow morning, I'm going to head to school and see about reflowing the motherboard: yes, baking my motherboard until golden-brown (well, not literally). From my research, conventional ovens take 385F for about 9 minutes for a good reflow, so that might be what I try if the school route fails. I'll be sure to give you guys the full details!

Interesting, I have never heard of doing that before o.o I shall have to google this and figure out what it is this does.
O_o Why are you going to put the mother board in the oven?
tifreak8x wrote:
Interesting, I have never heard of doing that before o.o I shall have to google this and figure out what it is this does.


qazz42 wrote:
O_o Why are you going to put the mother board in the oven?


So as you guys hopefully know, modern electronics are constructed by soldering lots of tiny surface-mount components onto dual- or multi-layer printed circuits boards. This is a great system, and is very reliable as long as you leave the PCB alone. However, physical stresses like bending or flexing and environmental stresses like extreme board temperatures can cause solder to gradually make a less reliable connection. This motherboard displays classic signs: if I pressed the outside of the case near a particular connector during boot, it even forgot it had RAM. The solution is to "reset" the solder to its factory condition. By putting it in an oven and gradually heating, then gradually cooling, you actually re-melt all the solder on the board, causing every component to get pulled back to its optimal position. You then gradually cool it down (carefully not disturbing the oven too much) so the solder re-solidifies with hopefully all the connections on the board repaired.
Ah, ok, so you are sort of using the same fix that people use on xbox360s. Makes sense then.
Fair enough, if it fails, at least you have a nice tasty cooked motherboard, be sure to share ;D
tifreak8x wrote:
Ah, ok, so you are sort of using the same fix that people use on xbox360s. Makes sense then.
Exactly, that's what it works out to be. It turns out that school does indeed have an oven that I can use for the reflowing, but I'm concerned that it's too small and won't give even heating.

Edit: Oven pre-heating, foil on baking sheet, three foil balls, motherboard. I have the three foil balls with two on blank areas of the underside of the PCB and one on the chipset chip on the underside, since I'm afraid it might fall off.
*bump* Amazingly, it works! I'm stunned.



So I baked it at about 375F (my oven's dial is not very fine-grained) for precisely nine minutes and zero seconds. I pre-heated the oven for fifteen minutes, and situated the board on a foil sheet on a baking sheet, supported by four foil balls, one at each corner. When the nine minutes was up, I shut off the oven and opened it about 5".



I left it for precisely 20 minutes, then carefully opened the oven the rest of the way, removed the slightly-warm motherboard, and let it sit for another ten minutes. Next I completely reassembled the tablet, which was somewhat time consuming; I only ended up with two extra screws! Rolling Eyes The final result, finally booting (for now):



Once I get an OS installed, if I can, I'm going to be undervolting the graphics chip, since it doesn't have a good heatsink. My research indicates that undervolting it can be very helpful in preventing heat damage in the TC1100.
That's pretty awesome sir Kerm. Hopefully you have little to no issues with installing an OS onto it to see how it will work.

Which OS do you plan on installing on to the device?
tifreak8x wrote:
That's pretty awesome sir Kerm. Hopefully you have little to no issues with installing an OS onto it to see how it will work.

Which OS do you plan on installing on to the device?
I'm planning on Windows 7. I'm very mystified on what particular item, though. If I unplug the power adapter and boot, the graphics glitches seem to reappear for no adequately-explained reason. If I unplug after it boots, the graphics issues don't appear, and if I restart after unplugging the graphics glitches stay gone. I'm mystified. I'll press on with an OS though, once I get a hard drive for it.
*bump* I ended up re-baking the motherboard later the same evening, because the video issues recurred. I think that the fact that the motherboard was slightly bowed after the first reflow/baking session might have been a problem, so I re-baked it, this time for precisely nine minutes at about 400F, as closely as I can calibrate my oven. I also placed foil balls under the center of the motherboard as well. When it cooled for twenty minutes, then came out of the oven and cooled for an additional half hour, I reassembled the computer and found it to work, so I installed software and such. It continued working for about 24 hours, after which the problems unfortunately recurred, sporadically at first, and now more regularly. My research indicates I might still not be heating it quite enough to exceed the reflow temperature of the solder, so at some point I might try it still hotter for a slightly shorter amount of time. If I do so, I'll let everyone know.
*necrobump* I'm afraid I've long since given up on the poor machine, over three years later. Tonight it meets its demise in the form of a trip to the trash. The funny thing is that although the first laptop I bought was going to be a tc1100, like this machine, I ended up with the much better Toshiba m205 because the seller of the tc1100 was illiterate and also skeptical of my 0 feedback score at the time.
  
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