Friday, November 21, 2014

Cable network graph on imp.guru

Quick follow-up to my Fixing the cable post from last year.

I never looked for anything else after Cosm went down to plot the numbers from my cable modem. There wasn't really a good enough alternative and I couldn't be bothered.

Since then SparkFun has launched their data service which seemed nice but didn't provide a plotting feature so again, I couldn't be bothered.

Then along came imp.guru which does exactly that so now I don't have an excuse to put off updating the script anymore.




The link is imp.guru/f2z

It has some limited use for me because I can check how temperature affects things and if something breaks I can see whether it was the result of a long-term process or not.

Otherwise I promise that it's just as interesting as watching paint dry.

Monday, November 17, 2014

Lenovo IdeaCentre A600 Restoration - Heatsink and conclusion

Continued from the previous post.

So the heatsinks in this thing were toast. Because the machine no longer used an MXM card I didn't have to worry about that one but the CPU cooler was still a big headache.

Remnants...


After all where am I going to find a replacement heatsink for an obscure all-in-one pc for an affordable price no less?

Do I try and get heatpipes and rebuild the heatsink myself? I really didn't want to..

I found an ID number on the demolished remains of the original and to my surprise, actually found a seller on eBay. A clearing house in China that had no idea what it was for and only had it listed by that obscure model number. Haggled the price down from $60 to $25 for 4 pieces including shipping.

Better than spending hours on bending and soldering heatpipes.
They didn't want to sell me just one so now I have 3 extras.. (Though unlikely, if anyone wants one for the price of shipping, contact me on one of the addresses on the right).



Heatsink issue solved!

I thought about replacing the front glass. I even had a glass pane cut and masked for painting.




But then I realized I despise glossy screens so ended up just painting the plastic frame that I would've glued the glass onto. It works for me.





Installed a T9600 CPU, 8 gigs of ram and 2 SSDs. All of which I got from eBay.

Secondary SSD install:

Professional mounting solution


That cable is also hacked since it originally ended in a micro-SATA connector (which is basically a regular SATA connector combined with a smaller power connector that lacks the 12v rail).
I separated the usable SATA connector with a saw and added a standard full-size power connector in place of the weird one. Thankfully 5 volts is all this SSD needs.




I have to say I'm very happy with the performance and how it turned out overall.
I've been using this machine for the past 5 months (including writing these posts) and it's been rock solid.

I'm glad I managed to save it from the landfill. 

Sunday, November 16, 2014

Lenovo IdeaCentre A600 Restoration - VGA hack

Continued from the previous post.

I'm sure this project is going to seem dated and futile to many. Why fix a past-generation PC and add an obsolete graphics port? What's the point?

The only thing I can say is that I don't actually need anything better than a higher-end Core2Duo and 8 gigs of ram for what I'm doing so I don't mind older gen hardware. It's also cheap.

The 21" display is an upgrade compared to the 19" 4:3 monitors I used before, but I still didn't mind using those that much and I have 2 of them like I mentioned in the first article, one of which still has "fresh" CCFL tubes.

So if I could keep using that one in conjunction with my "new" PC I'd be fine with that even if it's through VGA.

Looking through the schematics of the motherboard I found that it has unpopulated VGA output circuitry that ends in a set of test points.

You can guess where this is going.

A parts order and some hours later here's the (admittedly pretty terrible) result.



In my defense, these passives are 0402 and I used the same soldering guns I showed your earlier with really thin wire for the tips. I'm surprised I managed to maintain my sanity throughout the process and end up with something that actually works.

It took me a while to come up with a good solution for hooking up something to the test points in a way that isn't totally horrible. This is what I ended up with:

Those final two pins still bother me

Probably could've gotten an FPC connector with pin pitch closer to that of the testpoints but flat flex cable for that was around 5 times the price of this one. Go figure..

On the other end is

FPC connector at end of ribbon cable


It works pretty well even though everything's unshielded.




See the conclusion in the next post.

Thursday, November 13, 2014

Lenovo IdeaCentre A600 Restoration - MXM to Onboard Conversion

Continued from the previous post

Quite a lot of things needed to be changed to get the Intel GPU up and running.
  • Removing the resistors that disabled the onboard graphics and set up the MXM as default
  • Reconfiguring the clock generator (moving resistors and jumper links) to output the necessary clocks for the onboard GPU
  • Moving the backlight logic control circuitry (a few transistors and passives) from the MXM side to the onboard one (which also happened to the one the other side of the motherboard)
  • Moving the LVDS connector


Backlight control circuit components in their new location



I never invested into any modern soldering tools so this is going to be entertaining.
Behold my extremely professional tools made especially for the LVDS connector.



Two relics and some bent copper wire



Connector in MXM location


Connector removed



Pads cleaned



Connector in on-board location

 
Note how the sticker magically repaired itself (I'm cheating because I didn't take enough pictures)

Let it be known that I have since bought a proper soldering iron (though no tips that would've helped me with this...)

I did consider just buying and installing another connector instead of moving the original..It's a Hirose DF13-40DP-1.24V-55. I decided against it due to minimum order quantities and shipping costs. There's no way to keep both options alive anyway, so there really isn't much of a point. One of the connectors would be useless without moving a significant amount of components around.

So after doing all that (which took like a week of working on it after work) I had a machine that.. still wouldn't show anything on the display.
Everything seemed fine in dmesg now. The error message was gone and even the panel resolution was detected properly but the backlight just wouldn't turn on.

There is a small board with a capacitive sensor array and a microcontroller in the plastic frame that the protective glass was glued onto. You could touch the glass above it and it would light up to reveal 4 "buttons" (backlight controls and optical drive eject). I didn't have this board connected while testing which turned out to be a mistake. Embarrassingly enough it took me a few days to figure this out.
The board seems to be responsible for the backlight PWM control signal so without it there's no backlight.

After hooking it up I was greeted with a different problem. The inverter shut down after 2 seconds and would not start back up until a power-cycle. This is not a good sign at all and usually points to either the CCFL tubes or the inverter transformers being bad. Urgh!

At this point I was getting pretty annoyed with the project so I left it alone for a couple of weeks contemplating whether I should just toss the whole thing.

In the end I took one of my monitors apart and hooked up the CCFL tubes to it's inverter to make sure they weren't bad. They weren't, so the issue was on the inverter board.

DARFON 4H.V1561.091 inverter board


Not the transformers though, they checked out.
No ic pinout, no datasheet, no schematic. I painstakingly de-soldered and tested 90% of the components of the board separately. Everything checked out.
The least likely suspect - the controller chip - was looking really suspicious at this point. The only problem being that this chip (LX6512CPW) in this package (TSSOP) is simply not sold anywhere.

Replacement inverter boards cost as much as I paid for the whole machine.
Do I give up and hack in a universal inverter board after wasting so much time on this? There's no way it would fit into the case and brightness controls wouldn't work properly. Urgh!

As a final Hail Mary attempt I contacted MicroSemi, explaining the situation. I didn't think they'd really bother with a samples request for a discontinued product used in one-off repair by a hobbyist.


They did!


Brand new LX6512CPW sample in nice plastic case


It works!



Wooo-- wait.. why does that picture look weird?

Hrmm?


Some pixels are the wrong color...

I double and triple checked the LVDS connector visually. Couldn't see anything wrong. Continuity checked the cable, checked out.

After the fourth disassembly and spending an hour looking at it with a magnifying glass and poking at it with a multimeter while double-checking the schematics I finally found it. Barely visible adjacent pin short at the very base of the LVDS connector. @#!$!@%

Couldn't even get it out with solderwick so I ended up having to break it apart with a needle ...

But then it finally.. finally worked.


So now I had a functional machine converted to use the onboard graphics with a repaired inverter. Nice!
Slight problem... I can't use a dual monitor setup with this machine
... or can I?

Check the next post to find out.

Monday, November 10, 2014

Lenovo IdeaCentre A600 Restoration - Intro

This was a pretty lengthy project so I won't post it all in one go, this is just the beginning.

Some background info:
I've been using the same Core2Duo workstation (actually a ThinkPad on a docking station) with dual monitors for quite a while.
I managed to buy another 19" 4:3 Benq a while back that was the same model (and had the same fault) as the one I repaired back in 2009.
That one was probably close to 10 years old at this point and the CCFLs were beginning to show their age especially when sitting next to the "new" one.

What time does to CCFL tubes

I also sort-of wanted a widescreen monitor and more ram since the ThinkPad topped out at 4 gigs and I was constantly running out of ram while doing work (several browsers, IDEs and a VM running) which was driving me crazy.

One day while browsing an auction site, I found this thing.




A beat-up mangled all-in-one from Lenovo. It kind of piqued my interest because it was in such a pitiful state but could potentially be repaired/modded if everything the seller said about it was true.


So here's a quick initial rundown:
  • Powers on and stays on but doesn't do much else
  • Heatsinks forcefully removed with what I would imagine were bolt-cutters (Not a clue why someone would do this.)
  • Front protective glass chipped but display behind it intact
  • Two LVDS connector pads on the motherboard labeled "ONBOARD" and "MXM" with only MXM being populated (swappable?)
  • Supports Core2 mobile CPUs and DDR3-SODIMM (but only up to 8 gigs as I later found out) 

What a mess...



The seller tried adding some pins to the unpopulated pads but I won't hold it against him


I did some research and found the motherboard schematics online. According to those this board came in MXM and LVDS editions and it did in fact seem like one could be converted into the other with some (considerable) effort so if the MXM video card turned out to be toast like the seller predicted I could still do that.

Since I never heard anything good about MXM cards I assumed I'd end up doing that from the get-go if the motherboard was salvageable at all.
If not I would've just turned the thing into a monitor with an LVDS/DVI interface board off eBay so it seemed like I could get something out of it one way or another (assuming the display itself was fine)

Haggled a bit but still ended up buying it for more than I wanted to pay. Around $50-ish shipped.

By the time it arrived the chipped front protective glass had cracked lengthwise which I wasn't particularly happy about especially since it did so because of the lack of padding in the package *grumble*.

Thankfully the display seemed to have survived even that ordeal, or at least it wasn't visibly broken.
I did spend several hours removing broken fragments of glass from the plastic frame afterwards which wasn't really that much fun.

Hardware-wise to begin with I wanted to test whether the motherboard was functional at all. The fact that the SuperIO chip's pins were a big mangled on one side didn't bode well... Straightened them just a tiny bit and cleaned up the general area with solderwick.


Don't worry they're not really touching

A few resistors and capacitors were also destroyed presumably by the same incident that damaged the pins so I replaced those as well.
Then I made a bootable Linux thumbdrive, stuck it in, hooked up a keyboard and tried to get the thing to boot off  it by blindly guessing at key combinations for the boot source selection menu and watching the activity led on the drive.

At one point I started getting activity so I hooked it up to my LAN, fired up Wireshark on the home server listening for DHCP packets and tried again.
Sure enough the board was successfully booting into Linux and setting up the network, nice!
I SSHed in to check things out.

The board didn't seem to detect the MXM card at all and was trying to fall back to the on-board Intel GPU but had issues initializing it. I don't have the exact dmesg output anymore but it wasn't a terribly friendly error message.

Ran some more tests to make sure everything else was working at least and it seemed like it was.

Decided against trying to fix or replace the MXM card. I just don't trust the things and the onboard Intel GPU is more than enough for a coding workstation anyway.

In order to avoid any potential trouble I'm not going to post any links to or outtakes from the schematics since I'm pretty sure it was never meant to be public. You can find it online if you're interested. Certain parts/components are tagged with abbreviations for the two versions of the board, UMA (Unified Memory Architecture) referring to the system memory sharing Intel GPU and MXM for the obvious.
(For those who don't know: MXM is basically PCI Express x16 in a mobile form factor.)

Printed out all the pages (around 6?) where these appeared and got to work on the conversion.
I'll show you what I did in the next post.

Friday, November 7, 2014

[Random Teardowns] REX-C100 PID Temperature Controller


Device: REX-C100 PID Temperature Controller  
Origin: eBay / China
Reason for teardown: DOA
Impressions: Not impressed to say the least. A mains trace near the connector (which has spring-contacts to horrid quality tin-plated contact pads on the board) blew out on first power-up. Guessing the trace was damaged from the get-go. Overall mediocre quality.




The thing is a lot smaller than what I imagined















 Made in Japan. Sure it was.

















 Power supply and main board














 Display board















 Some closeups

PS(A): Definitely don't go anywhere near the ratings of the relay unless you solder wires directly to the board.



It is what it is

Wednesday, November 5, 2014

[Quick Tip] Determining a Type K Thermocouple's Polarity

Say you took apart a type K thermocouple connector and don't remember which wire was connected to which terminal.


Here's a simple test to figure out the polarity: The negative wire is attracted to a magnet


Neodymium sphere magnet sticks to negative wire



And in case your connectors aren't marked: The wider pin is the negative.