[Fixed] No LED light on Logitech K750 Keyboard

K750 charging under a lamp

tl;dr: Use a combination of a bright light and the reset technique (off ? CAPSLOCK + some keys ? on)


A few years ago while on holiday in sunny SC — a lovely place to visit, incidentally — I took the opportunity to purchase a Logitech K750 keyboard. The K750 was is a ‘solar’ keyboard- no changeable batteries, only solar cells to power it. I had been frustrated by other keyboards which needed battery changes timetabled in accordance with Sod’s Law.

They keyboard got passed on to my folks and all was well. However, since my dad passed away my mum has not used the computer as much, and so the lights in that room haven’t been on. When I went to use the computer there recently the keyboard was completely dead. Not even the red ‘sad face’ LED would light even if held close to a light source, which would normally elicit some response.

Leaving the keyboard in a decent amount of ambient light for a few days seemed to do very little to help.

Revivifying a K750

Enter Nut and his Tech, wherein they describe the reset procedure:

1. Turn off the keyboard.
2. While holding onto CAPS lock, keep pressing a few keys for the next 5 or more seconds.
3. Turn on the keyboard.

I did the above and held the K750 very close to a fairly bright bulb, and the LEDs sprang to life!

First the green happy face when still next to the light, then the red unhappy face when I took it out of full illumination.

So it works, for now. I was even able to type from the next room over where it sits charging beneath a mini anglepoise-type lamp.

On Cheap Hardware and Misbehaving Monitors

tl;dr: Cheap stuff can malfunction in unusual ways

I have a history of buying cheap hardware out of necessity. This has not changed in more than ten years. I wish it was different; but scrimping and saving and buying cheaper, off-brand is the only way I can afford to do things. That said, I am lucky be able to afford what I can afford, it is definitely more than some who are less fortunate.

I have a triple monitor setup, which some might call an unnecessary luxury; but with my eyesight being what it is more real estate means being better able to both fit a reasonable amount of things on the screens at a reasonable visibility.

Each of the three displays is 27″ and capable of a resolution of 2560×1440 at 60Hz. They are all also ‘cheap’ (relatively speaking) Korean knock-off imports- brands such as PCBANK, Crossover and DGM- the last of which I have at least come across before, in the form of the cheap TFT monitors referred to in the post linked at the start. At least they have a track record!

The third thing that these monitors three have in common is a tendency to malfunction; each in different ways. Taking them in the order of purchase, which dates from about five or six years ago to less than six months ago:

  1. PCBANK – The only one I bought new. Makes an audible noise when displaying white or mostly white (eg a a mostly text web page, such as Wikipedia). Also occasionally displays a distorted image for half a second before coming to its senses.
  2. DGM – intermittently blanked itself under Windows
  3. Crossover – If turned off or doing into standby, won’t turn back on for 5-20 minutes. Possibly a backlight issue. As a bonus, it was bought second hand and came with its integrated plastic monitor stand removed; the only way I could see to reattach it would be to separate the plastic casing, which I got halfway to doing before I figured I would purchase the monitor mount[s] I had been intending to for years

In addition, the transformer for the PCBANK or DGM monitor developed a fault which made my speakers screech like a banshee requiring me to take the highly-technical step of moving the transformer further away. Then it started buzzing itself, and needed replaced.

Those transformers are beasts, incidentally- 24V 5A or 120W.

These faults range from irritating to intolerable, but I reckon that if I had three monitors from reputable manufacturers at a commensurate price, I wouldn’t have the same issue with malfunctions.

Intermittent Monitor Blanking

tl;dr: Using a better-rated HDMI switcher improved the situation

For the past… maybe six months to a year one of the monitors I have has been ‘blanking’. That is, it will display properly most of the time, but intermittently go blank for around three seconds before the display reappearing. Strangely, the behaviour only occurred:

  • under Windows, not Linux
  • when using an HDMI switcher

For whatever reason, the issue got much worse in the last couple of weeks, where instead of happening once every five to sixty minutes (or sometimes not at all), it was happening back-to-back, several times per minute with an intolerable frequency. The situation was untenable.

I wondered about interference from other nearby cables, but adjusting them didn’t make any discernable difference. The monitor was running at 59Hz, but stepping it up to 60Hz made no difference either (and Windows 10 set it back to 59Hz). If anything, increasing the frequency may have made the problem worse.

So I figured the issue was the cheap HDMI switcher that I have. I don’t quite recall the circumstances of buying it (never a good sign), but it would have been cheap and therefore unlikely to be rated for 2560x1440x60Hz. After replacing the switcher with one with was rated for ? 2560x1440x60Hz, the issue seems to have mostly resolved- there was *one blank, but I think I can tolerate that.

For anyone else having a similar problem, allquixotic had the following to suggest for potential causes:

Periodic blanking could be: loose cable/connector; bad HDMI port; bad HDMI codec on the GPU/mobo; EMI interference on the cable (e.g., crosstalk by contact with another cable); or, yeah, insufficient cable quality for the data quantity being pushed… also could be pure software

you know, it could simply be Windows driving more data to the monitor; have you verified Windows isn’t overclocking the monitor beyond 60 Hz?

or it might be a GPU issue — Linux tends not to even use the GPU very often unless you’re decoding video, using the animation “whizzy” effects of a compositing window manager, or explicitly an OpenGL application (which in modern times could actually be a typical web browser, but not for everything)

*: I can’t quite explain why the problem only occurred under Windows, but I’ll wave my hands and say “driver differences” while nodding sagely.

Wanted: One LTO-4/5/6/7 Drive!

I am something of a digital hoarder. I have files dating back to one of the earliest computers that anyone in my family owned. I think I even still have diskettes for an older word processor, the name of which escapes me at the moment. As such, I have slightly more than average storage requirements.

At present I handle these requirements via a Linux fileserver, using 3TB drives RAID6’d via mdadm. On top of that I use LVM to serve up some volumes for Xen, but that’s not strictly relevant to storage.

Looking at the capacities of LTO makes me quite covetous. LTO tapes are small, capacious and reliable– with a few tapes, I could archive a fair amount of data. I could also move the tapes outside my house- and lo, offline offsite backups!

Sadly, drives are expensive, unless you’re stepping back relatively small capacity* LTO-2 drives.

At present, given the cost of drives, some back-of-the-envelope calculations show that for any reasonable** dataset, simply buying hard drives (at time of writing, 3TB is cheapest per GP) is the most cost-effective means of archiving. Given that is where the focus of development is, I don’t think this is likely to change soon.

I’ll just have to wait for a going-out-of-business auction, and hope the liquidators overlook the value of the backup system…

iPod Classic Volume Cap FTL

Edit: Forgot to include noise-cancelling / in-ear / tin can headphones as an option. Thanks George! Jump to the choices if you want to skip the blah.

Another update: I really must strongly recommend noise-blocking earbuds or similar. I bought a pair which have rounded soft material on the bud – essentially a cross between an earplug and an earbud. They were relatively cheap (about £8 from Argos), and the difference is substantial. They claim 30dB reduction or such, I don’t know whether that is true, but I can say that for many situations 40% volume is now sufficient. They do take a little getting used to, but once you use them you won’t go back – and your ears will thank you. Happy listening!

Continue reading “iPod Classic Volume Cap FTL”

The Glasgow Apple Store

…or as I like to call it “the place of Temptation, so tempting it requires a capital ‘t'”.

So I moseyed into the Apple Store, like I said I would. Pricing of the iPod Classic is in-line with the online Apple Store – £189. I wasn’t able to talk them down from that price as such; instead they let me know that they offer a 10% trade in, bringing the total to £170 ish. The guy in the store said the final price would be £161, and if they want to change me that that’s fine. I have student discount through my uni for the online store, but it no longer applies to music players, just Apple’s line of computers. Actually, the new MacBook is very steeply discounted (just over £110 off) which really, REALLY tests my willpower.

Now, the Geniuses upstairs in the store may be able to do something with my hard drive. I don’t know what they would charge for data recovery, and so I’m not sure if I’d be willing to pay; especially when I’m not sure of everything that’s on there. I think I’ll do my best puppy dog eyes when I go, and see if they at least offer to tell me what is on there for free.

Broadcom 4318 Working Under Ubuntu Hardy Heron 8.04 (Ndiswrapper)

In my dad’s PC is a wireless card – a Linksys WRT54GS I think. Anyway it uses the Broadcom BCM 4318 chipset, as seen by a quick lspci:

richard@hades:~$ lspci | grep roadc
00:0a.0 Network controller: Broadcom Corporation BCM4318 [AirForce One 54g]
802.11g Wireless LAN Controller (rev 02)

Unfortunately the new b43 / b43-fwcutter package (installed from / by ‘restricted drivers’) stopped this working. I’m not sure why exactly; it’s possibly because it was designed for a later chipset (I’ve heard 04 for one of the chipsets), but in any case this is moot. It doesn’t work at the moment. This affects PCI cards, some internal laptop wireless cards, and some removable wireless cards.

Now, the card worked under Gutsy using ndiswrapper. So, that’s what I tried to get this working. There is a post at the Ubuntu forums that details how to do this. I’m going to briefly reproduce the procedure here because quite a lot of people are interested in getting their card woking, but thanks to Mazza558 for the info.

1) Remove the b43-fwcutter package
sudo aptitude remove b43-fwcutter

2) Reinstall ndiswrapper

sudo apt-get install ndisgtk

b) Download and install wireless driver
WMP54GS Driver
wget http://roberthallam.com/wmp54gs.tgz
tar -xzf wmp54gs.tgz
ndiswrapper -i wirelessdriver/WMP54GS.inf

3) Create bash script to fix wireless
sudo gedit /etc/init.d/wirelessfix.sh
Into the file, put:

modprobe -r b44
modprobe -r b43
modprobe -r b43legacy
modprobe -r ssb
modprobe -r ndiswrapper
modprobe ndiswrapper
modprobe b44

Save it, then change the permissions to 755:
cd /etc/init.d/ && sudo chmod 755 wirelessfix.sh

And finally execute:
sudo update-rc.d wirelessfix.sh defaults

And then you can reboot and have working wireless, or just (as root) execute the commands you put into the wirelessfix.sh file.

NB: To get a root bash prompt in Ubuntu, execute:

sudo bash

Enjoy your wireless, on whatever card card you have!

Update: Ed points out quite rightly that can be somewhat hard to update using an internet connection if you don’t have a working wireless card. A situation not unlike what good is a phone call… if you’re unable to speak? In any case, you have a number of options, some of which may or may not be possible:

  1. Plug a cable into your ethernet port
  2. Use an old Ubuntu 7.10 Gutsy Gibbon CD to update from. This should Just Work, that is you put it in the CD drive and you will be asked if you want to use it as a repository source (or similar). If not, the
    command is your friend
  3. Download the .deb files manually elsewhere. Get both ndiswrapper-common and ndiswrapper-utils-1.9 (links to mirrors, not direct). Note that ndiswrapper-utils-1.9 has a couple dependencies like perl which you should have, but may not. Save them to a USB flash drive or whatever. Then use dpkg to install the deb files. Or:
    [insert USB drive and cd to it]

    [move USB drive to target machine, open a terminal and cd to the drive]
    dpkg -i ndiswrapper-common_1.50-1ubuntu1_all.deb
    dpkg -i ndiswrapper-utils-1.9_1.50-1ubuntu1_i386.deb

And you should be good to go, even if you are without an internet connection!

You know you have cheap hardware when…

So finally bit the “but it’s over £100” bullet and bought a new TFT monitor the other day. The monitor in question was a nice-looking 19-incher for roughly £110 (with free shipping to boot). I ordered it from eBuyer, choosing the delivery option that equated to “get it to me whenever”.

Two days later I got my delivery. Continue reading “You know you have cheap hardware when…”