Tagged: repair

That Time I Had to Reset My MacBook Pro’s SMC to Slow Down the High-Speed, Whirring Fan

Last night, I came home after a long day and found that my MacBook Pro would not wake from sleep after I took it out of my backpack. This is an occasional problem with my aging notebook, but after a reboot, it usually operates as it should. But this time, after I rebooted the machine, the fan spun to full speed, making that disconcerting whirring sound, despite the fact that the computer was not running any applications and was cool to the touch.

I opened up the computer and found that the outermost RAM DIMM had popped out of the slot. That would explain why, after letting it boot earlier, it reported only 4 GB of RAM. After reseating the RAM and securing each connection, I rebooted the machine again, but the fan kept spinning at maximum speed. Fuck!

This computer has been through a lot. I not only spilled seltzer on it, followed by black coffee. Eventually, the liquids damaged the keyboard, which I had to replace. And, let’s not forget about the time I had to solder the cable connecting the fan to the logic board. I suspected that whatever dislodged my RAM must have damaged the temperature sensor, and I dreaded that it would finally be beyond repair.

But then I noticed that MagSafe Power adapter, which was connected to my computer, was not illuminated—whereas it is always either green or amber. Moreover, the battery status lights also did not illuminate to show the charge level. Those additional symptoms led me to the underlying problem. The System Management Controller was corrupted, and I needed to reset it.

Key sequences: Resetting the SMC and Zapping the PRAM

Resetting the SMC is the new Zapping the PRAM. Image from Chickaboo Designs.

I’m old enough now to remember when our Macs would develop unexplainable problems, someone would advise us to zap the PRAM. In my over twenty years of working with Macs, zapping the PRAM never once fixed any mysterious problems. Would resetting the SMC do any good?

The Apple Support page outlines the steps for resetting the SMC for particular kinds of computer, such as portables with removable batteries, portables with sealed batteries, and desktop computers. In my case, I needed to shut down the computer, hold down ShiftControlOption with my left hand and depress the power button with my right hand at the same time. Once I did that, the lights on the MagSafe adapter came on.

Once again, I rebooted up the computer with baited breath. This time, as it had done countless other times, the fan came on at the normal speed.

While zapping the PRAM was for me pretty ineffective, resetting the SMC had a different result. It did indeed fix something!

MacBook Pro: Memory Slot 0 and Slot 1

My aging MacBook Pro (13-inch, Mid-2009) has developed a new problem. The memory sometimes “disappears” and one of the two 4GB DIMMs stops working. The problem manifests itself when trying to wake my computer from sleep: it won’t wake up! The computer is still running. I can hear the fan running and feels warm to the touch, but the display stays black. A hard reboot always brings the computer back to life, although this is not an ideal solution.

A few weeks ago, when I tried to reboot the computer, I got the dreaded three beeps. I removed the bottom case, removed the memory, swapped their locations, and reinstalled it. That fixed the problem. Both memory DIMMs were registering but one of them was reporting only 7.75 GB of RAM. System Profile reports Slot 1 as empty, but I couldn’t tell which one was Slot 1. As far as I can tell, the slots are not labelled.

When you look in “About this Mac” and select the Memory tab, it shows that my MacBook Pro has two memory slots. One on the left, with memory installed, and one on the right, which is empty.

MacBook Pro Memory Banks

Which memory slot is which? On the logic board, the memory sits vertically, one on top of another, not side-by-side. After removing a few DIMMs and placing them in different memory slots, here’s what I figured out.

Bank About this Mac Physical Location
0 Left Closer to Bottom Case
1 Right Closer to Logic Board

When the computer is upside down, you can see both slots. One is at the bottom and closer to the logic board. That is Slot 1. Slot 0 is the one that’s closer to you and the bottom case.

This should help you concentrate your efforts in determining whether you have a bad DIMM, a bad memory slot, or the DIMM is just loose.

Drivetrain Blues

Photo from Wikimedia.

I’ve been feeling sore from Saturday’s Climb-a-thon ride: no wonder I got dropped. My calves hurt more than usual so I’ve been taking it “easy” over the last couple of days: I didn’t bike on Sunday to Beacon, as I had wanted to, but I did jump on the track bike on Monday for my daily commute.

It was on this ride that I began to hear my chain slip off the gears, both of them, a problem that has been getting worse throughout the summer. The slipping was so severe that I decided not to ride the bike hard the rest of the day. On Tuesday, I didn’t ride the track bike at all and instead rode my road bike for my daily commute. It was a little much, and I felt like such a dork every time I had to clip out at a stop light. I looked even worse trying to clip back in to my pedals.

Exclusively riding the road bike is not a permanent solution: I have to fix my drivetrain. Hugo from Spokesman Cycles told me that I had to get a whole new drivetrain: a new chainring, a new freewheel, and a new chain. It would set me back about $80 for the parts and about another $40 for the labor.

Although that pricing doesn’t seem terrible, I’d like to try to replace it all myself. I’ve been snooping around and it appears that there’s a lot to this.


I need to figure out the size of the Chainring that I want. I currently have a 46-tooth in the front, and I would like something a little bigger so I can ride a little faster and a bit harder. I’ve settled on a 48-tooth.

Chainrings have a specific size, depending on the diameter of the bolt pattern, known as a bolt circle diameter (or BCD). One very nice guy at a very nice bike shop told me it’s 110 mm, and another guy at a shop down the street, run by some sketchy dudes, told me it’s 130 mm. The spec sheet for my FSA Vero crankset says that my BCD is 130 mm. Credit the sketchy dudes for possibly being correct, although they did try to upsell me on a used (possibly stolen) Sugino 75 crankset for $200.


I also have to replace the freewheel in the rear. I currently have a Shimano 18-tooth freewheel in the rear. I am considering a 17-tooth to significantly increase my gear inches.

Teeth 46 teeth 48 teeth
18 teeth 67.2 gear inches 70.1 gear inches
17 teeth 71.1 gear inches 74.2 gear inches

To install the freewheel, I can either have a bike shop do it, or I can buy the parts necessary to do it. A single-speed freewheel remover has to match the pattern of the freewheel. It turns out that I need to get one, such as the Park Tool FR-6, that is designed for BMX bikes and those with a specific Shimano pattern. I also need something to torque the removal tool, as the tool is basically just a screwdriver bit. I can use a regular crescent wrench, but a lot of gear heads recommend the Park Chain Whip tool since it has a chain on it to better secure the freewheel to the hub. It also has an hex opening that perfectly fits the FR-6.

While the chain whip is nice to have to secure the freewheel, installing the freewheel apparently only requires a little bike lubricant. Pedaling the bike will tighten the freewheel onto the hub, particularly on uphill climbs.


I need to replace the by-now worn chain. My bike requires a single-speed chain, which is sometimes marketed as a 8-speed chain, that’s either 18" or 332" wide by ½" long. I also probably have to remove some links. Hugo recommended I get the KMC Z510.

The collection of drivetrain parts are such that I should decide between 332" and 18". I’ve settled on the larger 18 since they’re thicker and presumably tougher, but going smaller might reduce some weight. It also appears easier to get 332" parts.

And such is the joy of bicycle repair and maintenance.

The above links to Amazon are affiliate links. If you buy something through those links, I will earn a commission fee.

What I Fixed, But Broke, But Fixed

My poor MacBook Pro has been through a lot lately. After spilling seltzer on it in July and then coffee in November that would require me to solder the fan back to the logic board, I had to do some additional unexpected repairs. To complicate matters, I also opted to replace the optical drive with a solid state drive and upgrade my 5400-rpm 500 GB hard-disk drive with a 7200-rpm 750 GB hard-disk drive.

Before I list all the parts I had to repair, a big shout-out is due for L2 Computer in Hell’s Kitchen. I’m glad to see that a computer repair and parts shop stills exist in Manhattan for cash-and-carry business, although judging from their pile of Priority Mail packages, it appears that a sizable chunk of their business is through the web.

  1. MacBook Pro Keyboard

    As I mentioned, it appears that the coffee I spilled took its tool on my keyboard. After six weeks, the entire home row of Latin alphabet keys stopped working entirely. Without plugging in an external USB keyboard, my computer became entirely unusable because I use a combination of those keys to log in to my computer. I took apart the entire computer and “cleaned” the keyboard with some rubbing alcohol. It’s not something I recommend doing, but it did help restore the keyboard to health for almost three months. Whatever corrosion the coffee caused must have returned because those same keys stopped working in mid-April.

    Someone on the web said that fixing the keyboard requires replacing the upper case. That’s hard and expensive. The iFixit Guide lists forty-two steps for removing the upper case and putting it together requires the same steps (in reverse). Also, the case lists on iFixit for just under $300.

    Since I had already removed the keyboard once, back when I cleaned it, I was brave enough to see if I could just find a keyboard to replace the bad one. L2 sold me one for less than $30. Replacing it took about ninety minutes.

  2. SuperDrive SATA cable

    When I replaced my optical drive with a solid state drive, I used one of these adapters so I can fit a 2.5” drive in the large optical drive bay. Since the day I installed the SSD, I had gotten intermittent I/O errors. Sometimes, after taking the computer from one place to another, the computer could launch any apps. If the computer was off, the ominous folder with question mark icon would greet me at startup instead of the reassuring Apple logo. The only way to “fix” this problem was to open the case and secure the cable back to the optical drive. I basically had to carry a #00 Phillips screwdriver with me like a big dork.

    In short, I had to buy a new SuperDrive SATA cable to replace the one that was either broken or I broke myself.

  3. MagSafe DC Jack

    In putting together the computer after replacing the keyboard, I drove one of those tiny screws securing the logic board into DC jack cable. In short, the computer would not receive any power from the AC adapter. To replace it, I cycled to L2 Computer and bought a used one for about $15. You can also find one on Amazon.

  4. Battery Indicator cable

    And as a last straw, when I was replacing the MagSafe DC Jack, I severed the battery indicator connector. I had thought that the indicator wasn’t a critical function so I had just let it go, but it turns out that the cable also controls the sleep and wake functions on the computer. Have you noticed that every time you “close the lid” on your computer it goes to sleep and when you raise to open the display, it wakes up? The battery indicator connector is critical for that function to work. Again, I rode my bike to L2 and replaced the battery indicator connector and cable with a used one.

My dad is an auto mechanic. When something broke on one of our cars, he would visit the local junkyard to find the part he needed. I remember when I lived in Santa Barbara and the fuel pump on my car stopped working, he came by one day to fix it, but we first went to the local junk yard to find a replacement. Yes, I am following his lead, but I should keep in mind that he didn’t break anything when replacing that part. I did.

The above links to Amazon are affiliate links. If you buy something through those links, I will earn a commission fee.

Breaker Bad

Hot and Smelly

Last night around 11:00 PM, we noticed a strong but intermittent smell of burnt plastic. We couldn’t notice the smell when we went to the open window, thinking that the smell was coming from outside the apartment, so we determined that it was coming from inside the apartment.

It turned out that the smell was coming from the electrical circuit breaker box in the kitchen. As we observed the box, we also heard a buzzing noise emanating from the box. Using a silicon oven mitt, to protect myself from electrocuting or burning my hand, I opened the box and began flipping switches. The buzzing had stopped once I flipped the switches off and on, but I wondered whether there was any inordinate heat coming from the box. There was: my infrared food thermometer read the temperature on the left group of switches as high as 200°.

We called the landlord, who in turn called an electrician, and had us turn off the power box in the apartment and the basement. We spent the night in the dark, with no lights, no air conditioning, or any fans. We did have a good stockpile of flashlights and batteries preparing for Hurricane Irene last August. As far as staying comfortable, the open windows and occasional cross breeze kept us cool last night. (It actually wasn’t all that bad so I’ll stop complaining.)

Bad Circuit Breaker

This morning, an electrician came and in a matter of moments replaced the defective circuit breaker. You can see in the photo that the breaker had developed some warping around the imprinted “900”.

It was fortunate that we were both home and vigilant about identifying the scent of burnt plastic.

If you smell a burning smell from your electrical circuit breaker box, you should…

  1. immediately turn off the breaker box (ours is in the kitchen)
  2. immediately turn off the main power supply (ours is in the basement)
  3. call an electrician to fix the problem

If it’s a hot summer night and have to wait until morning, suck it up:

  1. take a shower
  2. drink a glass of cold water
  3. open a window
  4. put a towel on the bed (this really helps me)