Wednesday, November 21, 2012

Cheated by the Keyless Entry remote. TU31

99% chance that a malfunctioning keyless entry remote is due to dead lithium battery. But what if two remote suddenly failed simultaneously, lithium battery reads 3V on voltmeter and the problem not solved after changing a new battery. This make me think of the faulty BCM body control module. After spending 30mins locating and dismantling the BCM, I feel that I should go back to the test the remote unit. On loading two 3V lithium battery ti a superbright led, I found the old and replaced battery drop from 3V to 1.5V.  What a shame being fooled by the "normal " looking unloaded battery voltage.



Sunday, November 04, 2012

Ninja 300 ABS

Most ABS Motorcycle can be identified to have ABS installed by looking for the presence of the ABS slot sensor. The sensor disc send signal to the ECU to detect the rotational speed of the front and tail wheel. It then control the ABS solenoid (So the fuse box will have a ABS realy / fuse slot as well) to operate the moderator and redistribute the braking force to the front and rear wheel.

Types of vibration sensor (Alarm)


1) Cheapest 10 cents sensor : a spring and a center wire type , this is for those cheap products like dollar worth bulgary / window alarm, wheel rotatatory led , ....
2) Piezo-electric couple with capacitor : Also cheap and for most cheap car vibration sensor alarm. VR sensitivity adjustable.
3) PIC controlled : with intelligent shock intensity and frequency counter, that a program will judge and avoid false alarm. VR sensitivity adjustable. However, mosre NC type (normally closed). Power consumption 11-17 mA.
4) Mercury 3D sensor... Good for slow angular movement.

Thursday, August 16, 2012

Fixing Whirlpool Refridgerator

Found that some "click" noise heard inside kitchen since last night. Then find the fridge is not cold any more. The lamp inside lit up normally. A clamp ammeter is used to check the current through the compressor (actually 2 wires lead to the compressor relay box, which in turn is plugged to the side of the compressor with 3 pins). The lable at the back of the fridge noted 1.5A @ 220V. However, the ammeter reads 5 A for 2 seconds and then down to 0A. A "click" noise is heard just before the cut out and this is assumed from the thermo protector in the relay box. What in my mind is that the compressor is seized as it does not run up at all. I make this guess as I found grease over the high pressure lines.
Then I read the net and found the relay box is the commonest fault. Then I go back and check
1) Voltage at the relay side : 3 pins -common, Run and start. The start/common pin reads erratic 180V-200V only , when the fridge is switched on.  This makes me suspicious.
2) Check resistance of the 3 pins on the compressor and looks for 2 coils Ohm reading. The sum of the smallest 2 reading should equal the highest value. Make sure the pins are not ground as well. My readings are 10 Ohm, 6 Ohm and 16 Ohm. So I suppose that the coil is not dead.

The relay is then suspected to be faulty. On opening up the relay box, I found chips of broken ceramic disc (later I found this is the so called PTC relay, or labelled as PTC thermistor from the fridge offical circuit label. This ceramic disc is shattered that the 2 pins (run and start ) lost their connection at the spring contact. The largest piece of the ceramic is realigned such that the 2 pin contact on both sides of the disc. Contacts are sanded and sprayed.

Then I pray and switch the fridge again. Wow.. the compressor works again !


The above is the compressor relay, which is usually found on the side of the compressor with 3 pin socket. The ceramic disc is found shattered. This PTC thermistor works by channeling current to the "starter" coil in first second. Temperature/resistance increases and current goes through the "run" coil circuit then.
Largest remnant is placed over the contact pins as a temporary measure, till I found a replacement part.

Sunday, June 10, 2012

Replacing Nissan Presage / Altima TU31 QR25 Engine mount

 Above is old damaged engine mount. The right sided (from compartment view) (near pulley/ engine belt side) is most prone to be torn apart.
 There are 3 hex nuts on the engine side mount. Two above and 1 at the bottom. You need long socket to loosen it as seen here the center pin is long.
 A long hex socket extender > 12 inches will make life easier.
 This is the second most difficult nut to be removed. I need two socket extender ( total length of 15 inches) to reach the chasis mount at the back. The regridgerant lines will obstruct you access.
 You can see the hex nut at the back of the chasis engine mount.
 This is the most difficult hex nut to be removed because the difficult access. Taking away the Relay mount/ bracket, I still cannot reach it with wrench or hex socket from above. The belt and pulley is obstructing all movement here. Finally, it took me 30 mins just to loosen this nut. I have to jack up the car (not engine) and insert the long long hex socket from below.
 The Relay box/ bracket needs to be loosened in order to reach the front chasis engine mount nut.

All hex nuts are loosened but are not taken away yet. The engine is jacked with a foot long hard wood under the tranny. How much is needed to jack the engine? I jack it up till I can observe the engine mount rubber edge  rising up by about 1 inch and the whole mount can be shaken loose by hand.
 The engine mount can be removed now. You need to lift the water reservior out.
The damaged engine mount with the center strut completelt torn apart from the rubber mount. The central strut kicking around and create clunking that is very obvious in the passenger compartment, whenever over bumppy road.

Saturday, June 09, 2012

Car Compartment noise and clunking over uneven road

My MPV is 5 years old and some noticeable metal clunking was noted over uneven road. Engine noise is also more pronounced at 2,000 rpm. The clunk is like metal knock against metal and happens 0.5 seconds after a bump/ uneven road. Worn engine mount was in my first suspicion but some forum mentioned worn sway bar bushing/ joint and even suspension may cause such clunking. My experience with my Mercedes is that the engine mount will last much longer and will only cause vibration rather than clunk. After thorough hammering, and kicking for loose parts ( jacking up both tyres and hitting , rocking the tyres, connection rods, exhaust pipe ... ) , no postive finding. But then after careful inspection, the motor mount near the engine side (TU31 / QR25 engine has 4 mounts : Font, rear ( not visible from engine bay), engine side, transmission side ), I find the engine mount collapsed by few centimeters and evident from the assymmetry of the rubber on the side. (Photo pending ...)

If you get a new engine mount and you can appreciate the difference.
The collapsed mount causing the metal strut rokcing up and down and hitting the chasis mount and results in clunking.

Replacement is simple and does not need to slip under the car (in which replacement of Mercedes E-class engine mount needs to do so ) .

All you need to replace the engine side engine mount ( Right driver side if you are sitting inside the car) :
1) Foot long 3 inches thick wood, to be placed between the floor jack and the tranny.
2) Floor jack
3) Hex Socket : size 12mm ( to remove the relay box that hinder the access to the engine mount) , 14mm (for the engine mount) . You may need a long 14mm hex socket as one of the screw of the mount is longer than usual.
4) A hex socket extender of at least 12 inches long, as the rear nut of the engine mount is not accessible .

It should be a 30-60 minutes job if all the tools are in hand. The part is cheap and cost only USD $ 60.

Sunday, March 11, 2012

Repair my 15 years old Fuji Hi8 camcorder


My antique Hi-8 camcorder is dead for a while and now I need to revive it to digitalized all my Hi8 collections. Video image output nothing but white horizontal jerky lines with audio nosies. 1 out of  2 times the tape cannot go into the slot correctly and camcorder refuse to play the tape. Though of some mechanical problem, like slipping belt. Head cleaning does not correct the problem.

Open up the case. No loose belt. Looking carefully how the tape failed to engage. Seems the camcorder has a protection mechanism that when the tape jammed the rotating drum Imay be due to dirty drum surface/ old sticky tape), it will eject the tape  automatically.

Took my few hours to learn that there are tracking screws for lead in and lead out tape. The incorrect lead in (reason???) will cause the drum slow down and the camcorder refuse to read the tape and eject the tape. After trial and error, bu adjusting the 3 tracking nuts in sequence, finally I can digitalized all my 15 years old tapes (which takes anther 7 days !)

IR Full HD 1080 Watch




This Spy watch performs as expected with this price. Video captured has size of 1920x1080, frame rate of "30" and data bit rate of 8Mbps. Performance is less than satisfactory but this is expected for this price.
 Yet it is fun to open it up and have a look of the design. Interestingly, there is a large 8Mb ram as buffer. MicroSD is changeble and is class4 . ATTO test of stock microSD card is very fast, indeed. The unsatifactory performance is likely caused bt the slow encoding chip  STK2365 , capturing in 15fps motion JPEG. I cannot find any information from alldatasheet. As far as I know , there is only 3 chip factories that is capable of making FullHD 30fps low cost encoding chip . Default setting will capture continuous video clips of each 20mins size 1.3GB .  If configuration is allowed to capture at 720p with 30 frames, then this is a very good gadget.
Performance in no light situation is good with help of IR, which gives some spotted reflection underneath the glass.