Buying From Ebay

Today I receive a package from the postman. It is an item that I have bought eight days ago from Ebay, a Timing Light.

The DIY LED timing light, constructed from a circuit pulled from the Internet, is dead and the old car still needs some working to be done, hence the decision not to repair but to buy one online.  It shouldn’t be expensive because it is just like a small manual flash unit with a trigger circuitry added to it.  After a while browsing at the choices available, I choose the one as shown above.

Bright LED DIY timing light

After unpacking the item, I did not try it out immediately. Instead, I make myself a cup of coffee, sit down and relax while enjoying the cuppa. Once done, I set off to work with it. Unfortunately it does not work but the small red coloured check light at the side of it do flashes.  I assume the fault is on the output side. Shaking the device, I hear sounds of something small bouncing between the walls.  Upon dismantling the device, I find that the xenon tube is chipped at one of its terminal ends. A case of rough handling I presume.

The damaged xenon tube

I have a spare xenon tube but the xenon tube is slightly longer.   I decide to buy one from the electronics shop near my area but could not find any, the shop does not hold stock.  So the xenon tube that I have goes into the timing light and it works.  The timing part is done and the next part is to set the rpm to the desired setting at 800 rpm.  But, the car has no tachometer.  In order to read the rpm, the pickup coil from the old DIY LED timing light shall be used to feed pulses to the notebook running freeware oscilloscope program.  To do this I need to clean the pulses and make sure the output voltage equals or less than the required voltage level of the notebook line-in, so as not to damage it.

Practically Done With The Car

All aboard

Whatever in the engine bay is back to where it belong. The old engine is a mess and the head too. In the end I just clean the transmission, put in new oil seals and just plug and play with the replacement engine. I did removed the carbon on the piston heads, valves and its surrounding areas though.  The car has moved since been immobile for more than a year.  The job is done but it is an old car so I need to look at other things that might need attention, mostly trimmings, brakes and the steering.

The wobbling in the balance shaft (top) even minute is too much for the plastic gear attached to it

Oil seals in the gearbox replaced

I now have an extra engine which I can rebuild and the transmission unit too. I can use it to power a DIY buggy if I have the raw materials, cutting, bending and welding equipment plus the will to do it.

Rebuilding CB23 Engine…again

The engine bay of the Daihatsu G200 cleaned out. Apparently not all of the oil is drained out

Actually I am not rebuilding this time but to replace the engine with the one I bought a week ago. I was told by the seller that the engine is in good condition and I just need to plug and play. The problem with the old engine was that I could not get one of the replacement parts, the oversize sleeve bearing for the balance shaft. Since I need transport, I assembled it back. When the engine gets hot, the oil pressure indicator lighted. It was OK for short travel distances of not more than half hour. The day I dragged the car for a long distance travel, the engine just died, luckily I was almost home.

The old engine and its replacement on the right

Well since the engine is down and out, I might as well clean it and transfer the water and oil pumps (which I bought new) from the old engine to the replacement engine. Also this time around I shall be tearing the transmission apart, clean it and replace the oil seals. After years of hard work, the oil seals are hard like wood. The problem with CB23 transmission is that to change the oil seals, everything have to be removed before you have access to the oil seals. Might as well clean it and remove the metal dust collected by the magnet.

Can't do without it, my crude trolley and winch. See the harddisk plates that are used as guide

There was quite a few interest in the CB23 engine, I might, if I am not lazy to lift my butt and clean the hands, show some pictures of the engine innards here.

Making Weather Resistance Outdoor BiQuad

Outdoor Biquad

This is a new biquad to replace the old one that have had a good wallop by the weather. The microwave resistance food container that I encased it with, is not weather resistance. Only left the biquad and the reflector plus some length of kite string somehow get entangled around it.

I have a 14cm frying pan that had its handle burnt at the bracket. I make use of the pan as a reflector and as a shallow waveguide. The biquad antenna itself is constructed from a transformer wire salvaged from a dead switching power supply. Since the old setup is using a BNC connection, the biquad is built upon a female BNC panel connector although now if I am building a totally new setup, I would prefer TNC. BNC is not up to par but it is almost there and cheaper.

Here is the construction in pictures.

Hole is drilled and the BNC panel connector attached

A look behind

A 10mm copper tube is cut, shaped and sliced, then wrapped around the thread. A piece of wire is then wound around and twisted to give a good mechanical and electrical connections. Lastly solder is applied using portable gas torch to fill in every nook and cranny

Biquad with sides approximately 30.5mm is constructed

Biquad is then soldered to the BNC panel connector and copper tube assembly. A 15mm strip of hard paper is placed beneath to give the desired distance between antenna and reflector. Soldering is not neat because the iron is not hot enough. Finally paint is applied all over

Rebuilding Home Audio Tower Speakers

The boxes before operation

As I said before that I’m not into music but I do listen to them and now the speakers are reaching its end of life. Having years of exposure to the high humidity of the tropics, the box’s boards are losing its bonding property. It is chipping away at the edges and the joints are opening up. Also the woofers have weakened and are not producing solid bass sound anymore. Since I have a few speaker drivers lying around I decide to rebuild the two speakers.

I have two pairs of 4Ohm car subwoofer drivers, one is a pair of an old 8inch and the other is a new pair of 10inch which are not up to par for the car amplifier. Each of the two different sizes woofer drivers will be paired in a single box connected in series so as to give an impedance of 8Ohm. The mid-range drivers which itself replaced the original mid-range drivers shall be reused. New tweeters and two-way crossovers salvaged from old speakers and kept will complete the setup for an 8Ohm nominal impedance speaker boxes.

The first step is the removal of all the drivers and tweeters followed by the stripping off of the dark coloured wood looking laminating sheets. A layer of fibreglass sheet is laminated at the bottom of the boxes and two layer of resin coats are applied to the rest, filling-in the gaps and cavities. Once the resin has cured, it is sanded before a layer of undercoat/filler paint is applied with a brush. The undercoat paint is then sanded and later covered with a layer of black paint. Again the surfaces are sanded but this time using fine grit sandpapers. Finally the boxes are sprayed with black paint followed by clear lacquer as the final touch.

The damage

Tuning and terminal holes

Enlarged hole for the 10inch woofer

Originally the boxes are of the vented type with tuning holes but are now covered and turned into sealed boxes for better sound clarity. Also as a departure from the norm, I have separated the boxes into two segments, one for the woofers and the other for the mid-range and tweeter.

Job's done

I am quite happy with the sounds, the bass is more solid and does not baffle even if the bass is cranked up. No problem in the high frequencies either, in fact now I can hear the instruments played clearly except that the mid-range is slightly muted. This could be the mid-range drivers itself or the two-way crossovers of which I do not know its crossover frequency, or whatever it is. A quick refresh reading on filters and crossovers, I come to know again about the 180 degrees phase change on the high frequency side. A reverse in polarity for the connections to the terminals of the mid-range drivers and tweeters solved the problem.