Fixing things - Christmas edition

After an incident with a fox in the garage last year and time taking it's toll, several of the Christmas lights were in-operational when we took them out the loft this December. Not to worry though. I decided to go for the repair option.

Outdoor lights

The outdoor lights were victim of the fox in the garage. Unfortunately from stress it bit through the cable... As it was on the low voltage circuit this was a simple case of stripping back the wires and re-soldering:

And here they are working:

Reindeer

We bought an outdoor reindeer back in 2020 (to add a bit of extra cheer to the Covid year) but almost immediately the LEDs started showing signs of rust. Not so outdoor-friendly unfortunately. It managed to stagger through until last year when several lights failed. So I stripped of the old LEDs and replaced with 2x 5m battery powered LEDs

Leaky Battery

Finally, I accidentally left batteries in one of the indoor lights over the year and they leaked and corroded the spring contact completely. Fortunately this was a standard AA size and a clean and replacement was enough to get the lights working again:

So a great outcome. Fixing three Christmas lights for less than £15 postage and packaging. And of course much less waste that would otherwise have been made.
 

 

Quirky Old Technology

I'm sure most people who at into technology and gadgets have a whole heap of old stuff lurking around in the back of cupboards, in lofts or garages. Well here is one of mine, still with box:

Yes, a Casio PB-100

Pop in a couple of CR-2032 batteries and it still works, albeit with a very faint screen

So I fired it up and entered in the first program in the manual (yes, still in the box)

10 INPUT "N= ", N
20 S=0
30 FOR I=1 TO N
40 S=S+1
50 NEXT I
60 PRINT S
70 GOTO 10

Lovely BASIC nostalgia feeling aside, this doesn't really do much but when I ran it I got some very strange behaviour:

ERR6 P0-20

(Incidentally, Change to MODE 0 and SHIFT 0 to run)

P0 is the program in slot 0 and -20 is line 20. Now, line 20 is the rather innocuous assignment of S=0 and ERR6 from the separate technical manual is :

Variable error

• Attempt was made to use the same memory for a numerical variable and a character variable at the same time
• Do not use the same memory for a numerical variable and a character variable at the same time

This is interesting, a character variable is assigned with a $, for example A$. So the assignment S=0 should be fine.

Then If I change to from S to P, say, it all works fine and then changing back to S it worked again. Very mysterious.

Yes, I did make sure I didn't enter S=O !

So no real idea what's happening, probably some path in the internal circuitry is failing but at least I managed to get it working in the end.

Fixing an old Multimeter

I have an old multimeter, a Metrix MX 001B. I believe this was made sometime in the 1970s. by a French company, Metrix, now Chauvin Arnoux Metrix. This had been gathering dust in the garage for several years until I started working on my Robot Arm Controller project.

The sensor wasn't working on one of the channels so I wanted to use the multimeter to test the circuit. Needless to say, when I dusted it off and tried to use it, nothing happened.

First, it needed two 2x LR1 Size-N batteries (duh!).

Second and more serious, the connection to the negative battery terminal had snapped off. Fortunately, it was relatively simple to solder a new connection onto the board.

And here it is working.

Not perhaps the most exciting video in the world!
(Uploaded to Blogger instead of YouTube so this isn't high definition. You have to kind of imagine seeing the needle move.)

Update 4th Jan 2016
In response to Halil Karakose's comment, I thought I'd include a view of the inside. This is all wonderfully simple and at a human scale compared to some modern circuits!

Old Hardware - Part 2

There were a couple of things to finish off before the Linux laptop was ready for use, solving the problem of storage and setting up an internet connection.

Storage was simple. The machine has a 20GB hard drive, of which 6GB had been partitioned to Linux. Once I had a working build, I lowered the Windows partition down to 10GB and created a new partition for scratch data storage.

I also had an HP Pavilion laptop that suffered from overheating. This was a widespread problem and HP patched the BIOS to keep the fan on. However, my machine broke with one of the common symptoms of the WiFi stopping. Incidentally as it was still under warranty HP were great about this and from shipping to return took only about 3 working days. Unfortunately, the underlying problem was still present and about 6 months later the video card broke.

At this point, the machine was out of warranty and I bought a new one (not HP). I did however have a perfectly good 250 GB hard drive. Amazon do pretty cheap 2.5in SATA to USB enclosures so I purchased one of these and got myself a 250GB USB drive.

The next step was to reformat the drive from NTFS to FAT32 so it could be used by Windows and Linux. Windows of course does not easily format FAT32 drives greater than 32GB but by good fortune the EaseUS partition master I used to partition the laptop also formats large drives to FAT32.

Secondly, the Wifi.

2002-era laptops likely didn't come with built in WiFi. Mine at least had a modem! At the time when I first got WiFi I installed a PCI card from BT. This didn't work after the default Lubuntu installation so I needed to set-up the card separately.

Instructions are widespread on the web. First, you need to discover the available PCI devices. The command to do this is:
lspci -vvnn | grep 14e4

From this I determined that the card was a Broadcom BCM4318.

Setting this up offline involves the following steps: 

As this is the b43 chipset install b43-fwcutter from the installation CD.

Next, download firmware files from http://downloads.openwrt.org/sources/wl_apsta-3.130.20.0.o and http://mirror2.openwrt.org/sources/broadcom-wl-4.150.10.5.tar.bz2 and copy to home (you need to sudo cp)

 Run the following commands:

~$ tar xfvj broadcom-wl-4.150.10.5.tar.bz2

~$ sudo b43-fwcutter -w /lib/firmware wl_apsta-3.130.20.0.o

~$ sudo b43-fwcutter --unsupported -w /lib/firmware broadcom-wl-4.150.10.5/driver/wl_apsta_mimo.o

Finally restart the machine.

I now had a working Linux laptop with WiFi and 250 GB of storage available.

Rejuvenating old hardware

I have an old Packard Bell Easynote One laptop I bought way back in 2002 (it wasn't even cutting edge then). When XP started slowing down under  the weight of windows services it ended up hidden, like so many other old machines, in the back of a cupboard. I think the last straw was trying to install iTunes.

I'm not one to be happy with perfectly good hardware going to waste so I eventually decided to get back into the world of Linux and install a lightweight distro to see if the laptop could be of some use. In this case I decided on Lubuntu.

On firing it up I discovered that the CD-ROM drive had died. This ruled out installing from a boot CD. Fortunately though I have an external USB CD-ROM so I decided to go down the route of setting up a dual booting system.

First step was to repartition the hard drive. This is a paltry 20GB. (Plenty of phones with more these days!) Bearing in mind the intention was not to use XP, I spent some time deleting data and uninstalling everything I could from XP. I got down to about 10GB, I'm sure I can do better...

After this I installed the free Partition Master Home Edition from EaseUS and used it to create a new Partition of 6GB. Some more partitioning would happen later.

Next step was to setup Grub. This is a boot manager that can be used to boot multiple operating systems.

1. Create a new C:\boot folder, copy initrd.gz and vmlinuz from the Lubuntu distro
2. Download Grub4Dos and copy grldr to C:\ and menu.1st to C:\boot\grub
3. Edit menu.lst and add the following to the bottom
   title Ubuntu Installer (hd0,1)
   kernel (hd0,1)/boot/vmlinuz
   initrd (hd0,1)/boot/initrd.gz
   Note hd0,1 refers to the second partition on the hard disk, i.e. Windows (The first partition is hidden)
4. Edit boot.ini (set  attrib -a -r -s -h c:\boot.ini first). Add C:\grldr="Start GRUB"
5. Put the distro CD into the USB CD-ROM and restart, select Start GRUB and follow the instructions to install

And here it is back in use.