WS-C2960S-24TS-S Fan Noise Reduction

May 22nd, 2020
I grew tired of our aging 16-port SMC 10/100 switch that had a couple blown ethernet ports and was causing problems with an AirPort Express in the back room. The switch last about 20 years, so I’m not complaining. Since that time, close to 24 devices or ports remain on our wired network and of those, several are now capable of gigabit ethernet. The time seemed right to upgrade to a gigabit switch.

I figured why not go all-in, so I picked up a Cisco WS-C2960S-24TS-S on the cheap on eBay for $30 shipped – I mean, I didn’t want to lose money here. You might ask why? We’ve got several Apple AirPorts that don’t do SNMP, but a managed switch does so I’ll now have a little bit better feel of network health. Upon receiving the switch, I soon forgot where these switches typically reside: noisy wiring closets with fans and other hot devices nearby. After firing it up in my shop and mounting it to the wall, the whoosh of the single fan was super loud. Sadly, I didn’t take sound measurements, but ask my wonderful kids and they’ll attest to it – you could hear it throughout the entire basement!

Since it was only $30, I figured why not fix this? The switch is mounted on the wall of my shop, in the basement, where it is rather cool all the time. That and our network doesn’t use the full bandwidth capacity the switch can handle. So, I opened the switch up with the intent of installing a step down converter:

The switch was easy to get into, just 5 sheet metal screws on the back side of the router. The cover easily slides toward the same side the screws were removed. Easy access!

Inside, there’s a small bundle of four wires connecting the logic board to the fan – looks like Cisco is using pulse-width modulation. Black is the negative, red seems to always run at 12 volts, yellow operates consistently at 2 volts, and the blue wire appears to be the tachometer measuring 4.5 volts when the switch turns on and reducing 2.7 volts when the router finishes its startup procedure.

The step down converters I have in-stock can handle input voltages between 4.75 and 24 – so much for stepping down the blue wire, but the fan’s red wire seems to be a candidate. In the pic below, you’ll see that I cut the red and black wires and spliced in a step down converter that reduced the 12-volt fan power to 7.3 volts. The kids approved of the noise reduction, so I wrapped the step down converter in some knock off Kepten tape and put the cover back on.

With the switch back on the wall, the fan is still audible, but I still wanted some air flow and didn’t want the step down converter getting too hot. Using my paid-for and excellent copy of db Meter which you can also use for free 5 feet from the switch, I’m measuring an average of 31 db. Success! After running the switch for an hour, the temperature is 29 degrees C – an increase of 2 degrees from what I noticed prior to this hack – will keep an eye on this. If the fan noise continues to bother us, I’ll consider getting another step down converter than can handle inputs down to 1 volt, a smaller fan, or maybe even taping over the inlet and outlet ports of the existing fan to further reduce air flow.

macbookpro5,1 sleep and DOSDude1’s Catalina

May 21st, 2020
We tossed DOSDude1’s patched Catalina on a macbookpro5,1 for a friend and noticed that the MacBook Pro wouldn’t wake from sleep and the sleep indicator on the front of the Mac illuminated, but did not pulse when the screen was closed.

This Mac is a 2008 machine, but it has been upgraded with a Kingston 240GB SUV400S37/240G. After the machine failed to wake from sleep and we restarted it, we found a crash log with a Sleep Wake Failure event.

Turns out the fix is easy. Go to System Preferences->Energy Saver and uncheck “Put hard disks to sleep when possible” for “Battery” and “Power Adapter”. Now the Mac goes to sleep and wakes up just as it should.

Cisco Network Assistant

May 18th, 2020

I downloaded 6.3.4 of the Cisco Network Assistant to configure this router, but it wouldn’t launch. I greeted with the error message “The application cna_mac_k9_6_34_en can’t be opened”.

To fix this, open and paste in the following string and then drag and drop the CNA app on top of the Terminal window:

chmod +x

In the my case, it looked like this:

chmod +x /Users/brad/Documents/Brad/Service\ Manuals/Cisco/WS-C2960S-24TS-S/firmware/*

After doing this, I was able to launch Cisco’s app!

Cisco Catalyst Switch and macOS screen

May 18th, 2020
I replaced an aging SMC 10/100 switch this weekend with a 7-year old Cisco Catalyst WS-C2960S-TS24-S switch that does 10/100/1000. The switch was easily returned to default settings by holding the mode button for 10 seconds; however, the web UI is then turned off by default. The web UI is enabled through the switch set up program, which required my MacBook Pro to make a direct connection to the switch console port using a USB cable. Previously, I would have relied on the ever-trusty ZTerm, but its not currently compatible with Catalina.

The following steps allowed and screen to make a direct connection to the Cisco switch:

Last login: Mon May 18 08:51:17 on console
brad@MacBook-Pro ~ % cd /dev
brad@MacBook-Pro /dev % ls –ltr *usb*
ls: –ltr: No such file or directory
cu.usbmodem14101 tty.usbmodem14101
brad@MacBook-Pro /dev % screen tty.usbmodem14101 9600

After making the connection with screen, I was able to run through the setup process, during which I assed the Vlan1 port an IP address of so I could reach the web UI on my network.

macOS old certificates

May 4th, 2020

I was trying to install Mac OS X Capitan on a macbookpro5,1 and during installation came across the error message:

“OS X could not be installed on your computer. No packages were eligible to install. Contact the software manufacturer for assistance or quit the installer to restart your computer and try again.”

Turns out what is causing this error are Apple’s own expired certificates. The workaround is to install Mac OS X with the computer’s clock set in the past. Follow the directions posted on Apple’s website and re-posted here:

1. Use Disk and erase the drive you want to install OS X on.
2. Connect to a wifi network or plug in ethernet and download OS X through the App Store. Install as you normally would and arrive at failure point regarding no packages being eligible and an option to restart.
3. In the upper right hand corner of the screen, turn off wifi (top right) and, if necessary, unplug ethernet cord.
4. Go to Utilities-> type this without quotes “date 0115124517”
5. Quit Terminal and choose the option to restart (wifi will reconnect automatically or if using ethernet go ahead and reconnect the ethernet cable.
6. The Mac OS X install should continue as expected.

Streakin’ Brother HL-L8350CDW

April 30th, 2020

The above-referenced color laser printer has been a beast of a machine, easily the best color laser of the three I’ve owned, including an Apple Color LaserWriter and a Samsung CLP-415NW. The Brother is now over 4 years old and well off of its warranty, yet its still on the puny original toner cartridges that came with it. Part of that is due to the addition of these reset gears (search eBay for “Reset Gear for Brother TN331 TN336 MFC-L8600CDW HL-L8250CDN L8350CDW”) that tell the printer to keep going because plenty of toner remains:

Reset Gear for Brother TN331 TN336 MFC-L8600CDW HL-L8250CDN L8350CDW

Lately, I’ve noticed prints have been looking dirty, see left picture below, there is extra black toner all over the page giving the paper a gray look and some vertical black streaks are present in the middle. Cleaning the printer’s four scanner windows and four corona wires helped a little, but the output shown on the left, below, remained.

Each toner cartridge has a gear that slowly rotates over the life of the cartridge. The printer reads this gear and guesses how much life and toner remain. When I covered this gear with a reset gear, I had effectively told the printer “New cartridges have been installed!”, when in fact the same old cartridges were still in place. As a toner cartridge ages, it allows more toner to come out, which is what I was seeing in the picture on the left, below.

The fix is easy, just tell the printer to update its color calibration. The color calibrated procedure helps the printer adjust its voltage and reduce the amount of black toner that is released. Here’s the procedure and all you need is access to the printer:

1. Press any key on top of the printer, near its LCD screen, to wake it up
2. Press the “down arrow” button 6 times, the “OK” button 3 times, and the “up arrow” one time.

The printer will run through its color calibration process, which takes about a minute. After it finishes the calibration, try printing again. The printed output on my machine went from left (before color calibration) to right (after color calibration):

Windows Print Server and Catalina

April 30th, 2020
I’ve never seen good instructions for connecting macOS to a Windows Print Server, specifically when you want to manually type in the name of the Windows Print Server and printer, like you can do on Windows. Indeed, you can do this on a Mac too:

1. From the app you want to print from, choose File->Print…->Printer:->Add Printer…
2. This step is necessary once time and you can skip in the future: add an “Advanced” button by following these instructions.
3. Click the Advanced button, change “Type:” to “Windows printer via spoolss”, and in the URL: field, enter the name of your Windows print server and printer name, as shown in my example:

4. Customize the Name: and Location: fields to your preference.
5. For the “Use:” field, choose your printer driver and if it isn’t listed, you may want to install it now – you’ll need to know the Manufacturer and model of your network printer, otherwise try selecting one of the “Generic PostScript Printer” or the “Generic PCL Printer” options.
6. Click Add.
7. Enter details about your printer if prompted, I was connecting to a Konica Minolta network printer, so I had lots to enter, copied from a Windows PC. If you don’t want printer finishing options, leave the options on “none” or go back and choose a generic driver.
8. Click “OK”.

Printing via Bonjour/AirPrint is much easier, but my work is Mac-hostile and disables these protocols, so I’m forced to use the method above or manually enter each printer’s IP address and use LPD.

** UPDATE 5-4-2020**
The dark printing came back along with missing black toner vertically in in each printed page. Turns out my toner cartridge was low on toner.

Also, whatever you do, don’t do like I did and try running paper or cardboard along the toner cartridge’s roller. Seems I shoved a plastic flap in the wrong direction and wrecked the cartridge, so my attempt to refill a demo cartridge failed. I replaced with a high-capacity cartridge comes with the reset wheels. When the behavior above returns, I’ll know I just need to fill the dam cartridge with more toner, but the color calibration steps might help you get a couple more good prints and won’t hurt your printer.

Silicon Power A55 1TB and macOS

April 19th, 2020

Last week, I purchased a Silicon Power A55 SSD (1TB). I’m temporarily using the A55 to boot a 2015 MacBook Pro. The A55 boots up the MacBook Pro when connected via a USB to SATA connection, but the behavior is different when using a FireWire cable to SATA connection (Seagate GoFlex FW 800 cable).

With the A55 connected to GoFlex cable, the MacBook Pro boots part way up, but then a circle with a slash appears across the screen:

Picture of A55 connected via FireWire

A55 connected via FireWire

Anyway, I filed a support ticket with Silicon Power to resolve this situation. It could be that this drive is not fully compatible with FireWire interfaces – stay tuned.

Pico and line numbers

April 12th, 2020

For some reason, I never seem to see the keyboard shortcut in Pico for showing the current line number. This post will help at least one person, me.

Pico refers to the ability to see line numbers as “Cur Pos” and the keyboard shortcut to enable it is by pressing the Control and C keys. This works in Catalina on a Mac, yay!

Could not activate cellular data network fix

March 28th, 2020

I’ve found with some jailbreaks, including iOS 13.3 and unc0ver, that I’ll be trying to use wireless service with my provider T-Mobile and I’ll get the following error message “ Could not activate cellular data network” and my mobile data won’t work.

Fortunately, Luca Todesco’s fix still works! I found a way to shorten it if you’re jailbroken:

1. Download MTerminal with Cydia or connect to your phone via SSH.
2. Open MTerminal (or make a SSH connection), type the command “su”, tap the “return” key, enter “alpine” for the password, finally followed by “return” again.
3. Enter the following commands and press return after each line:

chmod 777 /var
chmod 777 /var/mobile
chmod 777 /var/mobile/Library
chmod 777 /var/mobile/Library/Preferences

That’s it! I didn’t even have to restart my phone.

Others out there say they’ve uninstalled TetherMe to fix this issue, but this had no effect for me.