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Saturday, February 10, 2018

Trying my hand at mining


Just to learn what's up I decided to try crypto coin mining

Already have a system with two moderate graphics cards, that are getting old by gamer standards.  But lets see what happens
AMD Radeon R7 200 series 2GB

Decided after some googling to mine Ethereum on Nanopool.
This was a somewhat random decision based on googling what is the best pool and what is the best coin to mine.   Ethereum is at least a more well known coin that my coinbase account wallet holds so I thought that might help me not have to sign up for another wallet somewhere.   Signing up for coinbase was a long involved process of verification that i don't want to repeat for fear of identity theft.   Bitcoin mining seems over subscribed at the moment.

Downloading Claymore seemed pretty dodgy.  Followed instructions on
https://nanopool.org/   Ethereum quickstart.   Made up the the long addresses i needed.  I guess they are just your own invented string.  Who knows.

Readme in claymore says

For AMD cards, set the following environment variables, especially if you have 2GB cards:

GPU_FORCE_64BIT_PTR 0
GPU_MAX_HEAP_SIZE 100
GPU_USE_SYNC_OBJECTS 1
GPU_MAX_ALLOC_PERCENT 100
GPU_SINGLE_ALLOC_PERCENT 100

In Windows 10 is easy to set it permanently in Control Panel\System and Security\System\Advanced\Environment Variables.

and it says
For multi-GPU systems, set Virtual Memory size in Windows at least 16 GB:

"Computer Properties / Advanced System Settings / Performance / Advanced / Virtual Memory".
My SSD is fairly full so i set it to 16-20Gb

copied in start.bat from the config.  Windows complained about running it.   Wince

Start .bat says failed, you cannot mine with this GPU.  
Bonaire, 14 compute units



















Install Catalyst v15.12 for old AMD cards; for Fury, Polaris and Vega cards use latest blockchain drivers.
https://support.amd.com/en-us/download  doesn't show catalyst 
Updated drivers to 18.12

Still no dice.  Searched on the DAG error and I find:

https://ethereum.stackexchange.com/questions/17694/cannot-allocate-big-buffer-not-enough-graphics-memory

It says a 2GB card is now worthless for mining.   Need 6GB or more.   Oh well fail.   I'm not in a hurry to rush out and buy an overpriced graphics card and run up my electricty bill.   This was just to learn more about what goes on in mining.

I may try a different coin/pool to see if I get the same result.

Friday, December 22, 2017

P0141 Replacing the oxygen sensor in 2007 Honda Accord EX 2.4L


There is lots of videos and help around the net for this one, but maybe details of my experience will help someone because there are a couple twists.   This job is something that an average person with a good sense of humor can do.  It is an exercise in inconvenience but not mechanically complex.   It doesn't take any more tools than a socket wrench and a jack stand.  You do need a cheap tool to remove the sensor that you can buy when you buy the sensor.

Check engine light comes on.    Within a day I get the notice for my bi-yearly emissions inspection.  Life is like this sometimes.    Need to fix it today.   You can see i also need an oil change.



 My 20 year old OBD reader (can get the auto parts store to do this for you also) says P0141 Faulty Heated Oxygen Sensor (H2OS) Bank 1 Sensor 2.   Number 2 means the sensor on the catalytic converter under the car, not the one on the exhaust manifold under the hood.   My car is a 2007 Honda Accord EX 2.4L 4 Cylinder.

This could be due to bad wires, but most likely the O2 sensor is just bad, this car is 10 years old now.
You can look under the car and see this thing on the side of the catalytic converter.    I didn't do any diagnosis, i just replaced the sensor.




These are not too expensive, used to be a lot more.  I bought this one for $26.

You also need a special socket wrench.  I understand that auto parts stores may lend you one for a deposit, but they are only a couple bucks if you buy a cheap one, and this was the cheapest and worked just fine.






Parts came quickly.   The sensor has a long wire that runs through some clips and eventually has a grommet in the floor of the car under the passenger's seat.  Nuts!   It is under a flap of carpet that you could possibly access by pushing the seat all the way up and reaching under but removing the seat is actually very easy and makes this job less of pain.  The wire plugs in to a connector under the seat.

Do your self a favor and remove the seat as the first step.  Just take out the four bolts, two in front and two in rear under some plastic covers that snap off and back on.   Bolts come out easily with a socket wrench and the seat lifts up and you can reach the connector.







Unplug it and push the grommet and wire through the hole in the floor.   Here it is hanging out the bottom of the car now.


I'm not a fan of being crushed under my car, so i jacked up the front right wheel and put a jack stand under it, next to the jack.  I chocked the two rear wheels and pulled the emergency brake.   That created just enough room to get under and do the deed.   Still very awkward.


Reached under, put on the socket tool ,attached a socket wrench, wiggled and pushed and sensor was stuck tight.  I took a small sledge hammer and hit the socket wrench a few times.   Not an easy task while reaching under the car.  Eventually it budged and I could use the socket and wrench to remove the sensor.  Touch and go there for a while.  I knocked a lot of rust off the cat in the process.  My heat shields were already attached by some big hose clamps from home depot because they had come loose years ago.

The white plastic clips come off with a little pry from a screwdriver.  I removed the old cable from the clips.




Installed the new sensor with the wrench.  Routed the cable through the clips and pushed it and the grommet up through the hole in the floor.



From inside the car i connected the cable and pushed the grommet into place.

Reattached the seat without any issue, lowered the car.   Here is where the fun part begins!

Started up the car just fine, and the check engine light is still on.   Read the codes and it still says P0141.  Played around a bit starting the car and reading it.    Check engine light is still on and code persists.  Looks like I need to reset the code.  My old reader won't erase the code, it just says Err when i press and hold erase.   Dang.  Tried many times.  Can't reset the code.

I decide to take it to the local auto supply store and get them to reset it.   They tell me they aren't allowed to do a reset.   Some posts say you can ask them to push the button yourself, but i didn't try that.   I get frustrated and go buy myself lunch.

I need to get the car emission tested and I have to clear that light TODAY.  While eating lunch and reading on the web I see I can disconnect the battery and press the horn to drain all the charge as an alternative to erasing the code with an OBD reader.  However I'm out to lunch with no tools.   But when i get back in the car WooT!  The code has disappeared by itself.  Problem solved.  It just needed some driving and a few more starts to clear the fault code.

I drive immediately to the emissions inspection station and get it tested.  It passed!  Hooray.   A big win.


Tuesday, September 5, 2017

Heat pump inside air handler coils frozen


Didn't expect my blog to become an HVAC repair guide, but life brings what it wants to.

My rental house full of young "adults" and I get the call the AC isn't working on a warm day.

They say the inside unit is running, air is blowing, and the fan outside on the heat pump condenser is also running normally.  But it is still warm.   Is it low freon or a blown compressor?  I hope not, that will blow months of rent money earned.

I go check it out and there is moisture on the unit and floor, it is sweaty and the insulated freon pipe to the outside is all sweaty and dripping, even icy in spots.

The air filter is sopping wet and wont come out, it seems stuck in the unit and too soggy to pull out.

I take off the cover of the air handler inside (the lower one) and instantly see the issue.   The whole coil is a humongous block of ice.   Wish i took a picture.  A little quizzing of the occupants and I get an admission that somebody turned the AC down to 60 because they were hot.

It's possible that there is low freon, but i'm betting this is user error.   I left them with the fan running and the AC unit off, telling them it will be 2 days to melt that mess.  Luckily it is only 80 today and supposed to be cooler tomorrow.

Went back after three days, luckily the weather was cool so the lack of A/C didn't get any complaints.  I replaced the filter and checked the coil.  All back to normal.  Turned on the A/C and it worked fine and cooled normally.  No harm done.  Whew.


Thursday, April 20, 2017

Heat pump won't cool, condenser outside clicking and won't run


Not a lot of pictures here because i didn't think this fix would be the epic that it was.
The system is a generic International Comfort Products.   Inside the box I found that Trane, Tempstar, Heil and ICP units use a lot of the same parts.  So pretty much ignore the brand name on the unit.

First hot day in a while and the wife switches the heat pump to cooling mode and when I get home she complains it is not cooling.

Quick inspection reveals warm air blowing and the outside unit - condenser - is not running when the thermostat says it is cooling.   The strangest thing is the condenser outside is quiet except for a fairly loud clicking about once every 2-3 seconds.

The solution was that the solenoid for the reversing valve (inside the outside condenser) was bad.  It was shorted out.   Replacing it is easy and can be done by opening the unit and removing one nut and plugging in the wires.  Cost was less than $15 and can be done with only a socket wrench.


Here is how i figured it out...  I bit of a comedy of errors but I got there in the end.

Google searching doesn't help. So i decide to start swapping parts.

I open the access panel on the outside of the condenser.   With my finger feeling i discover that one of the relays on the control board is doing the clicking.   My voltmeter shows the unit is getting both 240V and 24V power.   The contactor (big relay) coil is not powered, so something is not telling the unit to start.

I decided the control board might be broken and ordered one on ebay for $20.
Heil Tempstar Defrost Control Board 1087952 CEPL130547-01 CEBD430547-02A
http://www.ebay.com/itm/232274455696?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT



Picture of the contactor on the left, and the control board on the right.


When the control board came a few days later i swapped it in.  all the connections are pull off and plug back in.  just transfer the wires one by one.

All done, i go to turn it on and I find the thermostat is BLANK.   Measuring the voltage at the green/red thermostat wires after pulling off the thermostat from the wall, i find i have no 24V anymore.   At the condenser no 24V either.   Whaaa?  It was there before.  I either blew the transformer or something else did in the 4 days since I tested before.   

Upstairs in the attic I open the panel on the air handler.  The transformer is in the back in the lower right.  No 24V on it's output.  Remove it and find that the primary coil measures open. 



I buy one on ebay for $11.99



Comfortmaker Heil Tempstar 24v Repacement Relay Contactor 1050699 HQ1050699HW


http://www.ebay.com/itm/222179588108?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT


When transformer comes I swap it in.  Now I have 24V power.  Thermostat is working again.   Outside the condenser is clicking again.  A week with out cooling and a total fail.  I'm right where I started.   It was not the control board.

At this point I got lucky.  I played with the thermostat and I find that the unit will heat, but not cool.  In heat mode the condenser starts right up and heat pours out.  That is the big clue.  Googling heat and no cool problem I find quickly that the reversing valve is likely the issue.   The reversing valve switches the direction of flow of coolant.

Reversing valve is inside the the outside unit.  I have to take the top off with the fan and reach down.   The reversing valve looks like this. I didn't take a real picture, this is generic picture.   On top is the solenoid.   When I disconnected the wires from it, the clicking stopped.
I measured the voltage at the solenoid and it was getting 24V.   There was no magnetic field from the soldenoid (put a screwdriver near it and it should be attracted) and resistance was about 1.5 ohms.  It should be 10-60 ohms.   The solenoid part (blue in this picture, but red in my unit) comes right out by removing the nut you see on the side.

I ordered a new one for $12.75.  
Trane American Standard Heat Pump Reversing Valve Solenoid Coil COL05901

When new solenoid came I swapped it in and everything worked! It took nearly two weeks waiting for three parts in a row but at least i saved a lot of money despite my bumbling.

After thinking about this repair I think the 24V transformer was the root cause of blowing the reversing valve solenoid.   The PRIMARY of the transformer was open when it was blown, which makes no sense that I blew it swapping parts.  Perhaps the 24V over voltaged the solenoid and blew it.   So that makes me feel better, i replaced the bad transformer in the process.



Thursday, December 22, 2016

Fixing broken USB power port on Samsung Galaxy 6S Edge


Suddenly one day the USB cord won't stay in and the phone won't charge.  Closer inspection i can see the tab in the middle seems missing.  Must have broken off when i was carrying it around with the external battery plugged in.  Dang.  I can charge it wirelessly for a while but that is going to get really inconvenient in the car.  I didn't buy the damage warranty, and the phone isn't paid for yet, so I can't just get a new phone.  So I dive into make the repair.

The repair was a success after all, but yuck this is a terrible phone to repair.  Count on destroying the back if you ever want to open the phone.  It is made of glass and stuck to the back with adhesive. The upside is the USB port is easy to swap once the phone is open, only one ribbon cable needs to be unplugged and a minimum of disassembly.

Watched this:
https://youtu.be/4qjcbBdpeTY  that I found here:
http://recomhub.com/blog/samsung-galaxy-s6-and-galaxy-s6-edge-charging-port-repair-guide/


Then I bought this:
Charging Port: Samsung Galaxy S6 EDGE USB Dock Flex Cable + Mic VERIZON SM-G925V
http://www.ebay.com/itm/301833434493

It looks like this phone requires heating up to break the glue.  The video doesn't mention how to re-glue it.
https://www.ifixit.com/Guide/Samsung+Galaxy+S6+Rear+Glass+Adhesive+Replacement/44897

and you end up buying a new back with adhesive Back Housing Glass Cover For Samsung Galaxy S6 Edge G925

http://www.ebay.com/itm/Back-Housing-Glass-Cover-For-Samsung-Galaxy-S6-Edge-G925-/111924107555?var=&hash=item1a0f325923:m:myU_u3n0hGTJ_8FSJwAxeWw

I will update the blog when the part comes... parts here.   Started repair.  No photos because my phone is the patient in this repair.

Heated the phone back with my heat gun and used the temperature probe, this has the problem of the phone getting hot and hard to handle.    The clean opening in the youtube video was impossible to duplicate, the glass back cracked immediately when i began to pry on it with an opening tool.    I also left some small scratches on the frame, no biggie but i'm glad it is my phone not someone else's.   The phone back was completely shattered by the time I worked around it and loosened it from the frame.

Very glad I bought a replacement back before I started.  I bought because i thought i would need it for the adhesive.  Turns out I need it because the old one is shattered by removing it.

Here is what the back looked like after i pried it off.  Wow.   The USB board that was replaced is also shown.

This is the new back I bought




Pressed on the back of the battery and wiggled a bit and was able to remove the circuit board from the frame.   The big surprise was that the sim card needs to be pulled out of the top of the phone.  I never noticed there is a small cover on the top of the phone where the sim is inserted.  Duh didn't occur to me that this phone doesn't have the sim card inside.   Until the sim is out you can't take the circuit board all the way out of the frame.

Replaced the USB board without further dissembling the phone.  I could snap the ribbon onto the underside of the main board by just lifting it slightly.

The bad news is i can see i scratched the inductor on the back of the frame and broke a trace at the edge of the black square in the process of removing the back.  Arrgh.  Either wireless charging or NFC may not work now and i'll need to see if i can get that part.   Looks like it is readily available:

Middle Frame Bezel camera Repair Parts W/NFC Chip Qi For Samsung Galaxy S6 Edge

http://www.ebay.com/itm/Middle-Frame-Bezel-camera-Repair-Parts-W-NFC-Chip-Qi-For-Samsung-Galaxy-S6-Edge-/351695135940?var=&hash=item51e2a9e4c4:m:movc9a-jeqXJ8dzLxTho_4Q

http://www.ebay.com/itm/351695135940?var=620659645388

Meanwhile i will reassemble and test the phone...

Bingo, wireless charging is still working... i'm somewhat surprised because a trace was clearly broken on the very edge of the black patch containing the inductor.

Plugging in the USB i get the battery and it shows charging... so the new part worked.

Made a call, charged the phone, took pictures, everything seems to check out ok.  Hooray.

OK so we have a winner.   The phone is fixed.  I will have to see if the NFC works next time I'm at a store, it is possible it won't and i will have to open it again and replace the middle frame part with the NFC inductor in it.  When I do I will order another back because I'm sure this one will get broken opening it again.





Saturday, August 6, 2016

Replacing upper screen on Nintendo 3DS XL





Quick blog post to journal my experience replacing the upper screen on a Nintendo 3DS XL.
The 3DS worked fine but the top 1/3 of the screen was black.   The owner said it hadn't been dropped so I had no idea if it was damaged, defective or what.    There is some chance the connector was loose but usually the screen just needs to be replaced.

I won't write step by step instructions, because I found this page that does an excellent (not perfect) job with pictures and steps.

https://www.ifixit.com/Guide/Nintendo+3DS+XL+Upper+LED+Display+Replacement/25070

Generally I think this is the most difficult 3DS repair that there is.  You need a magnifier, strong light, tweezers and patience.   You have to completely dissasemble the 3DS.  You have to open the top section to replace the screen, but you also have to totally take apart the bottom section and remove the motherboard to get to the connector.   The hardest thing is to thread the new ribbon cable through the hinge.   I did this by rolling it up and pushing it through and then unrolling it, using tweezers.  The guide doesn't give you any help in how to do this.    There are lots of tiny ribbon cables that have to be removed from there clamp connectors and re-attached later.  The plastic case and covers has some tricky clip and snap nibs, as well as the top section parts fall all over the place when you open it.

All that said, I did it!   You probably can too, but this is not for first time amateurs unless your DS is headed for the trash bin anyway, then what the heck, do it!   The replacement screen was not too expensive... I bought this one from Amazon.  It came quickly and fit.   So if you fail, you only lost $20.

Note that the screen has a silver edge, not the black bezel that the original did, so it looks different when you are done.   Check by before and after pictures to see what I mean.   Also the glass looks a bit different than the original.



There were cheaper ones, but this one was shipped from US and didn't look like too sketchy a source.

Dissasembly and re-assembly took me a couple hours.   As I said the hardest part was the large ribbon cable that has to go through the hinge, there is another cable also going through already so it ain't easy.

The first pass through I had some trouble with the top shell, getting the 3D slider in right and getting all the clips back on the cover.  I had squashed them a bit a first and it wouldn't close right.   I replaced the screw covers with squares of black electrical tape, prying them out damaged them and they didn't look right afterwards.

When it was all together, I turned it on and FAIL.  Screens flickered but stayed black.  Power light came on but no display.   Aaargh.   Opened the bottom and reseated the ribbons I could reach without removing the mobo, and then found the issue by accident.  I had installed the snap in IR module upside down.   Check the pictures, it will go on either way.  Once it was turned around, the system booted and the displays came on.   Win... almost.

The system froze every time i entered an application.   Opened it again, and reseated the WiFi module.  This is a common reason that 3DS freeze.  Looks like in the last round of fiddling and removing the cover, it was not seated properly.   Once it was snapped down tight everything started working.  Win...  Woot....!   Here is the system working.   Note the sliver bezel around the upper display, the only sign that this has been repaired.



Sunday, December 6, 2015

GE GSS25TGPEWW refrigerator hot, freezer OK.

My GE GSS25TGPEWW side by side refrigerator has a problem.  Today's issue is the refrigerator side is warm.  I mean really warm, even hot.  But the freezer is just fine and cold as ever.   One strange thing is that the top interior light is very hot to the touch.   Weird.

I fixed an icemaker issue on this thing - wow it was 5 years ago.
http://blog.workingsi.com/2010/10/ge-gss25tgpeww-refrigerator-broke.html

Note from future self - read the end of the blog first if you are going down this road, the fix turned out to be really simple and free.

First random google searches show I'm not the only one who this ever happened to:
This website is pretty good, you put in your model and it ranks possible issues.

http://www.repairclinic.com/RepairHelp/How-To-Fix-A-Refrigerator/58--852901-/Refrigerator-freezer-is-cold-but-refrigerator-is-warm-GSS25TGPEWW

Evaporator Fan
Damper
Thermistor
Main Board

Since the fridge is downright HOT, the defroster sounds like it could be the issue.  I also need to figure out where the evaporator fan is.   The only reason i don't like the evaporator diagnosis is that the freezer is nice and cold.

I need a picture to find where these parts are, and to see what is at the top under the light assembly that could be getting hot.

Gotta love google,   Image search leads me here:
http://www.appliancepartspros.com/parts-for-ge-gss25tgpeww.html

http://www.appliancepartspros.com/fresh-food-section-parts-for-ge-gss25tgpeww.html
Looking at this page the part#460, refrigerator Damper assembly Part Number AP3775595 is right where this thing is getting hot.   The damper is the little door that lets in cold air from the freezer.   We have a suspect!

Another likely suspect in the same neighborhood is the thermostat Part Number AP3192951.   It might be wise to order that at the same time.

Just to cover my bases I need to find the evaporator fan and see if it is working.
http://www.appliancepartspros.com/freezer-section-parts-for-ge-gss25tgpeww.html
This picture is totally not clear.   The evaporator and far are shown floating in front of the freezer section.   A cover is shown near some lights.  ugh makes no sense.  This is somewhere in the freezer compartment that I will have to dig out.

Some price research before I head over to look at the thing again
Part Number:AP3775595
Made by:GE
http://www.appliancepartspros.com/ge-refrigerator-damper-assembly-wr49x10091-ap3775595.html
they want $165

Amazon has this for $97, but it is not clear if it is the same part, or even compatible.

GE WR49X10091. My model is not listed, but search takes me here.


ebay gets me NOTHING when searching AP3775595.  Aha, i see that the AP number is a bogus appliance parts website number  the WR49X10091 is correct

Cross Reference Information
Part Number WR49X10091 (AP3775595) replaces 1055112, AH966602, EA966602, PS966602, WR02X11254, WR02X11255, WR14X10070, WR14X10071, WR14X10166, WR17X10869, WR17X10870, WR17X10871, WR17X10896, WR17X11508, WR2X11254, WR49X10101, WR49X10149, WR49X10150, WR49X10155, WR60X10051, WR60X10052, WR60X10070, WR60X10132, WR60X10174, WR60X10226.
Prices on ebay range from 85 to 120.
A few outliers cheaper.  Maybe worth doing the Amazon to get it fast.


I'm going to pull the unit from the fridge and see if I can jimmy it before I pull the trigger.
stay tuned..


Some quality time looking at the fridge. Cold air blows nicely out of the hole if i remove the damper assembly in the top of the fresh food section. So the evaporator and fan are working. The flapper door was shut, i poked it open with a screwdriver and put it back in. The fridge started getting cold. But after a time i went back and the door was shut again and it was warm again.


The hotness i felt before i think was just the lamp getting hot. There is nothing else in that area that could be overheating. So that was a red herring.


Alright, either the damper assembly is bad, the thermistor, or the main control board. I will start with the cheap components first. Ordering a damper unit....


The new damper came. Swapped it in. Waited. FAIL. The fridge did not get cold. $97.34 wasted. OK i also bought a $9.80 thermistor. I will swap that in next and see if that works. If not we are going to have to also get a main board. I'll still save money over a service call, but not as much as I'd hope. I can think about selling back the damper unit on ebay.


I panicked and order a new main board, figuring the thermistor can't possibly be the problem. It came and i swapped the new main board in. FAIL. The fridge runs just fine but nothing is different. The food side stays hot and the freezer is cold.


Looks like i will be selling the main board on ebay to get my money back, and I'll try replacing the thermistors.  I finally figured out where they are, the pictures on the web are useless.  There are two small oval grilles on the left side of the food compartment.  they snap out, and under the cover is the thermistor.  Was that so hard?
http://www.appliance-repair-it.com/refrigerator-thermistor.html

The misery continues.  I installed two new thermistors in the food compartment.  Snap out the oval grill, cut the wires, and use wire nuts to connect the new one.   Strangely the refrigerator is no slightly cooler but definitely still not working.   I feel only a wisp of cool air coming out of the damper.   Back to the drawing board.   My technique of part swapping is having one of it's worst runs ever.

I need to reevaluate how much cold air is coming from the freezer.  Maybe my original conclusion that the evaporator fan was working was wrong.   I will also look at the damper and see if it is open, since the fridge brain must be telling it to open up when it is so hot inside.

The only part left I haven't bought is the evaporator motor



The evaporator fan came.   Wow it is a pain to replace this thing.  You have to take the back panel off the refrigerator, take out the ice maker, the unit under the icemaker that turns the ice.   Several screws and jockeying around.   A youtube video makes it look easier than it was.
http://www.appliancepartspros.com/ge-evaporator-fan-motor-wr60x10185-ap3875639.html#autoplay

Finally I get the whole assembly open, and before I replaced the fan I plugged the unit back in to see if the fan motor was working.   Whirrrrr it was spinning like a champ.  So the evaporator fan motor was perfectly fine, no need to put in the new unit.  

Aaaaaaaarrrrgggggh!   Total frustration.  I've now replaced the damper unit, the thermistors, the main board, and stopped short of replacing the evaporator fan.  Everything is working but the fridge is still warm inside.

In debugging you arrive at this point for a couple reasons.   Either you replaced a bad part with another bad part.   Two things are wrong and you only swapped out one thing.  Or something incredibly stupid and simple is wrong that you are too blind to see.

OK it is not two things wrong, since all the parts are new at once.  It could be a bad replacement part but that is pretty unlikely and expensive and time consuming to check.  So lets look for something else stupid that is wrong.

I connected the old damper and looked at the flapper door.  Shut.  The new damper does seem to behave differently, the fan whirrs and the flapper door opens.  I ran the fridge for a while and checked it again.  Flapper door had shut!  Why would it shut when the fridge is obviously warm?  Unplugged and tried again.  Same thing.  Flap opens on restart, but shortly closes again.   Repeat with old damper.  Now i see it is doing the same thing.   Is the main board confused?

Lightening finally strikes me, small at first but then it builds.   While I'm checking the damper, the door is open.  Maybe the fridge shuts the damper when you open the fresh food door to keep the freezer from getting warm air in it.   So I decide to find the door switch and trick the fridge into thinking the door is shut so I can see what the damper does.

I look at the door switch and it looks weird.  I see a small microswitch that is too small to ever touch the door.   At this point all the pieces fall into place and I understand completely everything that has been happening.    Like the drawing room scene at the end of a mystery novel.

The little plastic lever on the door open switch had been knocked off.    I failed to mention that I had cleaned out the fridge the day before this happened and likely knocked it off then.  It just took a while to manifest.   The fridge thought the door was open all the time.  Thus the light was on solid, and heated up the fridge like an easy bake oven, making it hot, and making the light fixture burning hot.   The fridge thought the door was open and shut the damper to save the freezer and so none of the cool air made it to the fresh food section.    I looked around the floor and found the plastic wedge shaped piece under the edge of the cabinet.  I popped it back on and suddenly everything was right again.

There was nothing wrong with the damper, main board, thermistors or evaporator fan.   Why didn't I see the obvious before I began this process?   I was in a panic to fix this thing and parts take time to come, so I pulled the trigger without doing a thorough investigation.

Oh My God.  Bleepity bleep.  This was an epic fail of a repair job.  I bought $250 worth of parts and it took nearly two weeks with a broken fridge right at Christmas time.   All because of a stupid little piece of plastic knocked loose.   I will sell back the parts I pulled on ebay and try to get some of the money back.

Geez..  At least it is fixed now!


Tuesday, June 30, 2015

Logic Friday


Logic Friday

This is a tool for creating logic from a truth table you enter.  Very cool.  Free.  Wish I wrote it.

http://www.sontrak.com/index.html


Saturday, August 30, 2014

Epic Fail - Samsung Galaxy S4 swimming in salt water







This summer I went swimming at the beach. Played in the waves about half and hour. At one point I realized my Samsung Galaxy S4, less than a year old, was in my pocket. Nooooooooooo! I didn't think I had it with me, but I'm so used to carrying it that it has become invisible. It was inside a huge rubbery Otterbox Defender case.   Thank goodness I didn't lose it, I would have gone nuts combing the beach for it.

On the outside the phone looked fine. I immediately popped off the back and took out the battery. I had no tools with me on vacation so I couldn't do much more. I dried it out with a paper towel and put it in a bag of rice and left it. It had a few drops of water inside around the battery but didn't look too bad. Between the case and the phone, it seems pretty tight. Maybe it will be OK? Some people suggested I should rinse it with fresh water to get the salt water out, but that seemed like I'd be destroying it more, when it didn't seem terribly wet inside.



 I left it in for 24 hours and tried to power it up.  Nothing. Totally dead.   I left it to charge a while.  Still dead.   I took the battery out and tried to power it up, thinking maybe the battery was shorted.  Nothing.  Dead.

A voltmeter on the terminals circled in the picture yields 1.8V when the phone is plugged in, and goes away when it is unplugged.  This is the input for the wireless charging.  This gives me some hope that the phone is not a brick.  But it still doesn't power up.

I'm out of state with no phone and no tools.   I need a phone to live, so I sucked it up and went to the local Best Buy and used an upgrade to replace it with a slight newer Samsung Galaxy S5.  Ended up costing $100 and two more years.  But at least the pain of stupidity faded a bit with a shiny new phone.   Now I was free to try some more extreme measures to fix the phone.

When I get home two days later, and have my tools I open it up.  The phone has been in rice the whole time.

 Standard youtube video shows you how to open it.  It is surprisingly easy for a phone to get apart.  Once the screws are out, I used my fingernail.

https://www.youtube.com/watch?v=zm4f2XjQLAM


Things look OK at first glance, but close inspection and YUCK!  Maybe you can't see from the pictures but it looks like a friggin salt mine.  Salt is conductive and if it is not corroded, it is probably shorted in all kinds of places.





 There is salt everywhere, caked on the components.   I popped out the motherboard by lifting the connectors and rinsed it in alcohol.  I poured alcohol all over the exposed boards.  Wiped what I could and let it evaporate.   Once it dries it looks better, but there is still salt caked everywhere.  Can't figure out how to make it better.

I re-assmbled and plugged it in.  Still nothing.  Totally dead.  This phone may be a lost cause.
I'll add more if I think of a way to clean it better.   Maybe a fresh water bath will dissolve it better than water.

At this point a week has passed since it got submerged in salt water.  In hindsight I should have done this immediately.   The damage may have already been done.  I just didn't have the nerve.

I can't believe I did this, it felt so wrong!   I disassembled the phone and gave it a bath in fresh water.   I took off the cover and removed the connectors to the motherboard so that water could get underneath.  I did not totally take it apart. I rinsed the boards each a couple times and changed the water a couple times to get the salt off.  Never have I treated electronics this way!


Back in the rice while still disassembled.  I will let it sit for a day and dry out.


After it dried out I looked at it, and it is still full of salt.  This photo is bad but you can see salt caked around between the components.

I put the phone under running warm water for 10 minutes, and back into the rice.  Not looking good.

After the phone dryed, the boards don't look much better.  There is still salt caked in between the components.   Dang.   This needs some aggressive cleaning.

Strangely there is some minor improvement.  The terminals on the back of the phone circled above, now read 5V instead of 1.8V!!  So I have removed some of the shorting material.   However the phone is still totally DOA and won't turn on and no LEDs light.  I'll try charging for a bit but I should see a charging screen even with a dead battery.

Stay tuned.. but if this happens to you, don't expect to ever use your phone again  :).

Wednesday, July 23, 2014

Fixing Acer Aspire One AO756 Laptop w/Intermittent Screen



Quick post on a successful laptop fix.  I was in a hurry and didn't take pictures, so this post may be less helpful than average.   However this was an easy fix that anyone with a small screwdriver can do.

This laptop had an intermittent screen.  As the user manipulated the laptop the video would flicker, tear, invert, lose colors, etc.  Problem happened enough that it was really irritating.  Wiggling and re positioning made it work again briefly.   This was not just the backlight turning on and off, the video was being corrupted.  Backlight stayed on the whole time.   There were no obvious cracks or sections of the screen acting differently, so it didn't look like LCD trauma.

I thought the LCD panel was probably cracked internally or the video cable was broken at the hinge, as the video cables usually go through the hinges and this machine had a rough life.   My first thought was I'd being buying a replacement LCD but I was wrong.

To rule out the possibility that the video chip is coming loose/desoldered from the motherboard, I plugged in an external monitor.  Video was fine.  So the motherboard and graphics are working.

First I pried around the screen bezel and it pops right off.  No screws at all.  Four screws hold down the panel.  Flip it over and the video connector is on the back.  Removed and reseated it.  Wiggled and flexed the panel, cable and connector.   There really seemed to be no correlation to wiggling something around the screen, hinges, connector and the screen flickering.   More manipulation and I decided that the loose wire must be the other end of the video cable.   Snapped the screen and bezel back together.

Flipped it over and began removing screws.  Removed the battery. Several screws on the back surface, remove the hard drive cover and there are about 10 more sprinkled around.  You must remove them ALL.  None are hidden, thank goodness.  (actually one is next to the wifi module and was partially under a sticker)  They are little black Philips head.  Once they are all out you can pry around the perimeter and the keyboard and top cover pops off without much resistance.   If you miss one screw, the keyboard and top cover won't come off.  Pry it a bit and you will quickly find the one you missed.  Left the keyboard cable connected and folded top cover out of the way.   Underneath is another video connector like the one on the back of the LCD.   Follow the black wire bundle from the screen to find it.  Unseated and reseated and the problem went away!  W00t!

A bit of finagling and popping to put the cover back on and putting in all the screws. Good as new.