Fixing The National Step Challenge Tracker

20 December 2015

The Singapore Health Promotion Board gives out Actxa Stride step tracker at a nominal cost of SGD$5/= * to all Singaporeans who registered for the National Step Challenge.  At times,  the tracker will not work properly after cleaning it using water.   What shall we do ?  Throwing it away is one option,  how about fixing it?  
* it was free before 1 Dec.  The National Step Challenge is from 7 Novemer 2015 – 8 May 2016 

Why the Tracker Stop working?

The tracker is water resistant but not water proof.   Water might not get into the tracker through the weakest part,  that is the USB charging outlet.    

If one inspects the strap or the belt closely,  one can find that there is a stopper to prevent water penetration into the USB.  

But this stopper is not water proof.   Water can easily find its way into the circuit boards when the stopper or the strap is removed for cleaning.  Furthermore,  the tracker plastic cover is removable and therefore,  not water tight.

What to do Next?

Dry out tracker

Method 1

What’s required?

1. Hair dryer

2. A small package of rice

Dry out  the tracker.  Using hair dryer with “warm to touch” setting for at least 10 minutes.  This method might not  work if the water has penetrated deeper into the tracker.  In that case, leave the tracker covered with rice inside the package for about 1 week and let the rice extracts the  moisture out of the tracker.

Method 2

This method for technical savvy readers

What’s Required ?

1. WD40 and a tooth brush
2. Paper towel for cleaning
3.  Hair dryer

1. Open the tracker's plastic cover by working from the opposite end of the USB outlet,  using just finger nails or something such as a coin to pry open the cover.  One should expose the circuit board with a Lithium Battery attached to it by a pair of wires.  Observe the position and placement of the battery.   
2. Carefully remove the circuit board, making sure not to destroy the “soft sponge wiring  contact” that is attached to the touch button of the casing.

3. Try touching the shinning golden plate next to the display.  If the set is responding to the touch,  then the tracker is working;  otherwise,  the trouble is in the soft sponge wiring contact. Dry the sponge out carefully and thoroughly with the hair dryer for at least about 5 minutes and reassemble the tracker back to its original state*.

4. If the tracker just  does not work,  dry out any moisture that can be trapped inside components using hair dryer with “warm to touch” setting for at least about 10 minutes.
5. Spray some WD40 on to the tooth brush (but not directly to the circuit board as WD40 will spoil the display unit).  Apply the tooth brush all over the circuit board,  avoiding as much as possible,  not to touch the display unit
6. After that ,  dry the WD40  with the hair dryer.

The display should turn on and off after touching the shinning golden plate next to the display.   If there is no display after the cleaning,  try charging tracker as the battery* might be flat.   If all the above failed,  one has a faulty tracker.

      * the battery should be discharged completely before reassembled back to its original state

7. Assemble the unit in reverse order,  making sure the battery is the original position

Why the Tracker’s Touch Button does not respond ?

When the tracker is opened or dropped on the floor,  the button might not work properly or insensitive to touch.  But when one lifts up the tracker and read or touches the “shinning golden plate” of the circuit board,  the tracker works.  

Why?

The tracker button is capacitance type that sense the present of finger.  If for some reason,   the capacitance should change due to possible micro movement of the printed circuit board,  it might render the unit not possible to detect the present of the  finger.

How to Fix?

Resetting the tracker and let the tracker re-calibrate the capacitance on startup

How to Reset the Tracker when there is no other button?

If the tracker is working,  one can either reset the tracker by

a)     Try uninstall and reinstall the Health 365 software.  it should  reset and recalibrate the tracker;

b)   If that does not work,  try leaving the tracker alone for about a week and let the battery discharge completely;  after that,  recharge and start the tracker;
.

c)      If one is technical savvy,  open up the tracker and drain the battery out by using a 100 ohms     resistor connecting across the battery terminal.  The discharge time can be around 1 hour.  Do not short directly the terminals of the battery. Recharge the battery* and the touch button should work again.

* recharge only after assembling back with its plastic cover intact.

How do I know the Tracker has been Reset?

On the first charge,  the tracker should display “Hello” and followed by the battery charging sign.

Are There any other Simple Ways to Reset?

There might be other ways to reset the tracker such as using the reset pin of the microprocessor but the author could not identify any technical information about the microprocessor to try out the pins.

Duplicating Condominium Access Cards

17 December 2015

I lost my access card to my apartment the other day.  The management of the Condominium  wanted SGD$60/= for the replacement of the card and another $100/= as a deposit.  The market rate to duplicate a card ranges from $15/= to $33/=.  This article will give some basics about access card and where and how I duplicated my card.

The Basics

Most access cards used in Condominiums are for access through the main or side gate.  These cards are called “RFID” cards which stand for Radio Frequency (RF) ID Cards.   Embedded inside each card is a coil of thin wires and a microchip.  Most of these cards are passive type,  meaning there is no battery inside the card. 

 

When the card gets near a card reader,  the coil  will receive an RF signal from the card reader. This signal will not only power up the card but also activate the microchip inside the card to send a code to the card reader to open the gate for example.

Some of the cards are encrypted for additional security reason,  making them difficult to clone.  Fortunately or unfortunately,  most cards are simple cards that just stored an ordinary code for the card reader.

The simple ones will use a frequency of 125Khz as a transmitting carrier.  Some complicated ones that allowed codes to be encrypted are running at 13.56 Mhz which will allow more codes to be written to the cards.     

How to Duplicate EM Cards

1.  Non Encrypted EM Cards

These cards are  called “EM” cards as it was first developed by EM Microelectronic of Switzerland.  They are labelled EM4100 or EM4102 and they work only on 125Khz frequency. EM cards also operate at some other frequencies. 

2  What you will need to duplicate EM Cards?

      1. EM Card Reader Cum Writer (copier)

      2. EM card or EM tag

  

      One can purchase the EM card reader cum writer (copier) from vendors in AliExpress for about USD $15/=.  This EM copier also supports EM4205,4305 writable cards or tags as well as T5557,  T5567, T5577,  CET5200 and CET5577 cards as described in the  brochure.  The complete set comes with 6 credit card size EM cards and also 6 RFID tags as shown below.

 

The reading  and writing of the card is very simple as shown in the following video.

How To Identify Your Card?

Many cards do not give any clue about what type and model;  fortunately,  there is a simple way to find out because most card readers will have a brand name and sometimes,  if one is lucky,  also the  model number.  Surf the net to get the required information.

What if my RFID is not the same type as yours?

 Like any lock or key,  all access cards can be hacked and duplicated.  One only needs to surf the net and find a solution.  If one's card is  simply having a single purpose such as opening the door or main gate,  it might not be encrypted and one is likely to find similar tools to read and write the card.  A good tool to use is a 9 frequencies copier as shown here.

This tool will try to read almost any card and give a voice in English that will report something about the  card,  such as operating frequency or if it can read and write your card.

What if all the above does not work?

 One may try to purchase another more expensive and powerful copier  such as this shown here. 

 

According to the description,  the copier will display the read and write operations.  For access card that is encrypted,  this copier can also be hooked up to a PC in which a software provided will be able to analyse the card and help to identify and crack the code.  However,  the author has not tried this tool yet.

Are there other tools?

There are many other tools available in the market that can read and write the card but most of these other ones will require one to know how to use the software and do some programming in order to duplicate or break the code.

Can I use EM copier for copying HID cards?

 Not all copier can copy both EM and HID cards although they are of the same frequency.   HID cards are just cards that is manufactured by another company.  HID card has a more advance coding system,  enabling more secured codes to be written to the card.  It is always good to check with the vendor if one suspected that their access card has more advance features.  Copiers that can copy both EM and HID cards demand a slightly higher price.

Is EM4100 and EM4102  the same?

EM4100 and EM4102 are the same type of card except for EM4102,   being newer model,  has a unique chipset configuration that will  enable the card to be made thinner than EM4100.  Please note that EM4100 is not programmable.  One could try EM4305 or other series of compatible  RFID cards or tags.

What about other EM cards and other 125 Khz Cards?

EM cards are not necessary made for the same purpose and therefore,  they may differ from each other.   EM4100 are 64 bits read only card that once written,  cannot be rewritten.   The other card like EM 4205 and 4305 are 32 bits, whereas T5557 are 330 bits types that may not be compatible with EM4100.  On the other hand,  EM4200,  being replacement of EM4100/EM4102 EM4005/4105 claimed to be compatible with the latter.

Is it legal to copy access cards?

Under the  existing legal framework,  duplicating access cards is treated no difference to  duplicating normal keys.  There are many shops and outlets including those  reputable ones like  Mister Minit and  Soxxi Master are offering such duplicating services.

How to Back Up Windows’ Registry Permanently

11 December 2015

1.0  Introduction

Windows XP and other later Windows OS have built in restore function which one can save a copy of the PC’s registry and restore the PC to its previous condition should something go wrong with the OS.    Unfortunately,  this function can store and keep a copy of the registry provided one has allowed adequate storage; otherwise,  one would lost the earlier copies as they will be overwritten without any notification.   This article will provide a simple solution using a free software called “RegBak”. 

2.0    Where to Download

Can download from here  It has been used by many and no bug or virus has been reported. 

3.0    What is Required

3.1    Starting up

Install Regbak and fire up,  one should be greeted by this screen,  click NEXT   

   

It will bring to a confirmation and backup page where one can backup the registry into the designated folder

3.2    Restoring Registry (Using Windows 8 or 10 as example)

3.2.1    One can boot into Windows

Either in Safe mode or normal windows,  navigate to “Windows\regbak” folder and select the date.  Then click “REGRES.CMD”. Restart the PC.

3.2.2    One cannot boot into Windows

3.2.2.1 Windows 8,  8.1 or Windows 10

1)  Startup Windows Repair DVD.  Navigate to “Advance Option” and select “Command Prompt”.

2)      In the  Command Prompt,  type “D:” (without quotes;  same for all)  to change Directory to “D:” then type “cd windows\Regbak\” to navigate to the Regbak folder

3)      Open up the folder by typing “DIR/W” at the Command Prompt.  One should find the required backup folder,  for example “2010-10-23”

4)      Navigate to that backup folder by typing “cd 2010-10-23” and do another “DIR/W” to find the backup files, "REGRES.CMD"

5)      Type “REGRES.CMD” to run the program

6)      Restart the computer.

      

3.2.2.2 Windows 7 

When starting windows,  press space bar continuously and then press F8 as instructed until the follow screen shows up

 Click "Repair Your Computer",  follow the instructions until the following screen shows up

Click "Command Prompt" and following para 3.2.2.1  2)- 6) to restore the registry.

4.0  Safe Keeping of Backup Folder

      Safe keeping of the backup folder or files in another hard disk or a CD by copying the Regbak   folder and files from Windows\regbak folder.  In case of emergency repair,  just restore the Regbak folder and start the Registry restoration,  the PC will be back to its previous condition.

5.0  What will be missing?

This method of restoration will not be as powerful as Windows' system restore as it saves only a copy of the Registry. It will not check and restore missing programs for example. 

Unless one's PC is having hardware or disk problem, most likely one can restore your PC to its previous conditions without having to lose your files or information or reformat your drives except one cannot restore those programs or information that one has deleted from the drives.

 

Windows 10 Startup Problem After Changing Components

 27 November 2015

 Introduction

After one has changed some components in the computer with Windows 10,   one may encounter start up problem;  for example,  after changing the keyboard or mouse,  the keyboard or mouse will not work after startup and might just get hanged.   Do not panic,  this article will explain why and what you should do next

Why?

The OS has the “Fast Startup” function turned-on when you shutdown.  It saved the startup  data to a file called hiber.sys. When one starts Windows the next time,  it will simply load the startup data without verifying so as to speed up the starting.  Unfortunately,  the data of the new components one has just installed were not saved.

How To Regain Control?

1. Restart the computer,  this time select “restart”  instead of “shutdown”.  

But when one  changes keyboard or mouse, it might not be possible to select “restart”,  then

2. Enter into BIOS setup at startup (consult the manual,  usually press DEL or F2 key) ,  then select “Save and Exit”

Philips 170 S4 Monitor Repair

8 June 2015

Symptom

 This old 17” monitor  gave a blank white screen whenever it started.  Switching the main button on and off repeatedly or pulling the plug may reset the monitor but it will go back to white screen on next restart.  

What was wrong?

 A polyester capacitor labelled  as 0.47K275V-X2 (0.47 uf  shown as 2101 & 2102 220nf 275V in schematic diagram) has gone bad with only 2nf reading when it was removed for measurement.   Though not affecting the monitor screen greatly,  it was found that the 82 uf 450V electrolyte capacitor (2016 as shown in schematic diagram) has also gone bad.

How to detect faulty capacitors?

 Many capacitors have to be removed first from the circuit board and use a multi-meter such as the following to take a reading.

As this meter of mine has an upper range of 200uf,  capacitors higher than 200uf could only be measured by charging/discharging method using ohm meter.  A good capacitor will start with very low ohm and slowly increase to about 1000 ohms or thereabout.   

Ensure that the capacitor is always discharged before taking any measurement as the multimeter can be damaged easily by any electricity discharge.

Schematic Diagram of Power Board

This schematic diagram can be downloaded from here.

Reference

One of blogger's repair work 

TW64 Smart Bracelet

7 May 2015


There are many different types of smart bracelets in the market.  The most common ones are branded under Fitbit,  Garmin,  Xiaomi but the most popular one appears to be a brandless bracelet called TW64.

What is a Smart Bracelet? 

Smart bracelet is nothing but an electronic counter that can be connected to the handphone and/or computer through a Bluetooth network for data logging. Various brands have come up with different functions  for such  bracelets.  Most use it to count the number of walking steps.  Others use the counter to work out calories consumed,   sleeping movements,  time alarms etc.  Many bracelets have a built-in time clock enabling the bracelet to be used also as a watch.   The more sophisticated ones like FitBit has in-built a height sensor,  enabling proper logging of step countings,  up and down a staircase.

What's Good About Smart Bracelet? 

1.  It takes record of your foot step, It will always help you to "challenge" your own self that you can always make longer and longer walk.   The recommended daily walking step is 10,000 steps for a healthy person according to American medical research institutions.  Once one has taken exercising to be a daily routine and walk or run  10,000 steps,  one would feel very uneasy to stop walking

2.  If the bracelet counting is website based, it will enable your bracelet to be "monitored" by the vendor like FitBit.  One might be able to use the records to get premium discount from some Health Insurance Companies.

What is TW64 and why it is popular? 

TW64 has been marketed under several brand names.  It has a twin 64K RAM and a 64K ROM all inside a Quintic 2021 system-on-microprocessor chip (SOC) which consumes ultra low power.  The abbrev "TW" could stand for the word TWIN.  TW64 is popular because it is one of the most affordable bracelet that has almost every function of the more expensive cousins.      

What are the main functions?

1. A 24 hours clock with running dates and a battery counter
2. A pedometer that registers walking step counting which is used to calculate the distance traveled and the calories burnt.
3. Other functions such as vibration reminder,  alarms,  sleep monitoring etc

Construction 

The chip,  Quintic 9021,  is enclosed inside a plastic casing measuring about 17mmx40mmx10mm.  The back case can be easily removed by 4 small screws to expose the inside electronic as shown.  Unlike other bracelets  it  allows the battery to be replaced.

Synchronising 

Like any other smart bracelet,  one can synchronise TW64 to the Android or Apple handphones through bluetooth using a free software called "MOVNOW plus", downloadable from Google Playstore or Apple Store.    Unlike Fitbit or other more sophisticated smart bracelet,   MOVNOW is not web-based and therefore,  could only be synchronised using handphones.

Performance 

The TW64 was tested with a full charge and compared it against a Fitbit Flex by wearing them together on the same wrist as shown.

The sets are then taken for a 6 km walk and the results are compared as shown

It can be seen that TW64 and Fitbit Flex have quite similar step counting.  It is well within the 10% error range.

The Battery and capacity 

The battery is a lithium-ion polymer type of either 40mAH or 60 mAH capacity. The test set came with a 60mAH battery and the vendor claimed it is able to handle  at least 7 days usage and 100 days standby.  After 5 days’ testing,  the test set still have 3/5 of the charge as indicated by the battery indicator.

Pros and Cons

Pros

1. It is very affordable,  priced around SGD$20/= including shipping from Q0010
2. It is not bad looking.  The bracelet material feels like silicone and has a look like FitBit Charge or other more sophisticated and expensive model
3. Long lasting battery that can be used for 7 days or more on a 60 mAH battery
4. Can be used as a watch
5. The battery is replaceable
6. Can be used without the handphone

Cons

1. The software is not web-based and therefore,  the data loggings or recordings might not be accepted by Health Insurance company for any discount in health premiums
2. The vibrator is soft and the vibration might not wake up some heavy sleeper ;  moreover,  the wake up alarm will sound only once.
3. It is only splash proof;  meaning,  cannot be worn for swimming.
4. Must synchronise to the phone regularly or the data would be lost. However,  the bracelet can store some data over nights for next synchronisation.

Things to watch out when buying TW64 

1. There are many brands offering various model of TW64.  Some are older model that can only used for older Android phones or iphones that have Bluetooth of 3.0 or lower
2. Go for TW64 which has 60 mAH battery as the battery will last longer. 

Things to watch out when using TW64 

1. The weakest part is the 3 charging contacts.  Clean them every time with a paper tissue after each long walk to get rid of the sweat.

1. Do not wear it for swimming though there is no problem wearing it during showers.  
2.  

QN902X Application Notes

The application notes on QN902X can be found here. 

Instantaneous Heater – Electrocution in the Shower

2 September 2014

There was a report that a Singapore teen was found dead while taking a shower. It was not immediately known if he was electrocuted or just scared to death as an electrical outlet that was connected to the instantaneous heater was shown charred in this picture.

Observation

There was no further report on the death but it was said the family just replaced the instantaneous heater themselves. They found the boy dead, lying on the floor when they forced open the bathroom door after hearing the boy's screaming. The resuscitation did not help the poor child.

The picture showed that the heater wires, run on ordinary 3 core cable, might be directly connected directly to a heater switch which could have burnt out.  This did not quite indicate the boy was electrocuted.

The heater switch is also not a common one that use double-gang socket outlet box. The picture also shows that the house wiring is a very old type with exposed wirings running on the surface using wood battens. This sort of wiring type is only found in very old HDB flats or perhaps in SIT flats that have never been replaced. But this flat in Block 1 Hougang Avenue 3 is a HDB 3 room improved unit which was built in the 70/80.

It was also reported that the socket outlet box was installed inside the bath room.  This is not allowed under the present electricity codes in Singapore.

What could be wrong?

There may be many reasons causing the boy’s death. It is not known until the investigation has been completed.

But from the picture, it may be clear that the wirings and system was not a typical installation in HDB’s flat built in the 70/80. This suggests that the owner could have re-wired the installation.

PUB, the former utility board, made the installation of earth leakage circuit breaker (ELCB) a mandatory requirement for every new residency electrical installation in the 70s.

If the boy has been caused by electrocution, it may be highly possible that either the ELCB is not working properly or the re-wiring of the apartment has removed the ELCB.

What is an ELCB?

An earth leakage circuit breaker (ELCB) is an electrical switch that can sense current flow or leakage of electricity and trip the main switch to the apartment before anything damage could happen.

Most Singaporean homes are installed with such ELCB that can trip when the earth leakage is more than 30 milli-amperes.

In the past, the ELCB must have saved many innocent lives. If it is true about the electrocution,  this poor boy would have been saved if the ELCB had worked and trip the electrical supply.

Could it be a failed ELCB?

The ELCB could fail to operate because it is basically an electro-magnetic switch with mechanism that might get stuck in the closed position during operation. It is for this reason that all ELCB will have a test button.

Testing of ELCB should be done regularly. The best is once a month. This is because ELCB or the main switch board are often enclosed somewhere out of view and may subject to all sort of environmental exposures including possible moisture attacks,  rusting the mechanism.

Besides Testing ELCB, what can be done?

One could ensure always that electrical appliances are connected to the earth so that if there is any electrical leakage to earth from the appliance, it will first trip the electrical main before any human could touch them; also, if there is any human contact, the current created will have enough power to trip the ELCB.

How to ensure there is a proper earthing?

Invest in a multi-tester that would cost not more than SGD$30 from most electronic shops.  The meter is also available from many $2/= neighbourhood shops with a separate price tag.

Set the tester to the lowest ohmic range, say 1 to 100 ohm. Using one test lead touching the metal part of the appliance, the other test lead touching any metal part of the water pipe or tap. The meter should show some readings around 10 ohms and below. If it is more than 50 ohms, most likely one would have a faulty earthing requiring attention or rectification.

In the case of instantaneous heater, using one lead touching the metal part of the piping connector of the shower head and the other lead touching directly to the water facet that is connected to water heater.    

In case where instantaneous heater has a PVC outlet connector that does not expose the metal part of the heater such as those shown here having an insulated PVC connectors,  carry out as follows:

First, switch off the power supply, then remove the outer protective casing of the heater (usually fixed onto the heater with a bottom screw). Using one cable lead touching the metal boiler unit or any other metal part and the other lead touching the water facet directly.   When fixing back the casing, make sure it is fixing back to the original position.

Why test cable must touch water pipe or facet?

It is a mandatory requirement in Singapore that all wiring installations must have their earthing bonded to the water piping at the incoming mains.

By having one lead touching the metal part of the appliance and the other lead to the water pipe or facet, one can test roughly the integrity of the earthing system within the apartment.

If the earth readings are more than 10 ohms, it is good to check the earthing of the appliance or the actual electricity earth for safety sake.

The electrical installations in Singapore are always installed with an effective earthing resistance having less than 1 ohm.  There should be test reports submitted to the authority.

What if the water piping has a section consisted of PVC?

Water pipings are mainly metal pipes but sometimes, a section of PVC may be inserted. It may give false reading especially when there is no water in the pipes. If there is water, the multi-ohm meter should still give some good readings because water is electricity conductive. If there is any doubt about the integrity of the earthing, place the test lead to the water pipe before the PVC section.

What if the Ohmic reading is Still high?

Try pulling a power extension cord that has an earthing connector from the nearest power socket outlet  to somewhere nearer to the heater and measure the resistance between the extension cord's earth and the heater's earth.   If the reading is still high,  there is a poor earthing connection to the heater and one should call an electrician to fix the problem immediately.   This high resistance readings could be caused by the Teflon plumbing tape being used to seal the  pipe joints of metal pipes especially when there is a repair on the existing piping system.

Update 1:   2 Sept 2014

This picture showed clearly the heater was connected to a 3 pin plug.   Understand the switch socket outlet of a double gang type was removed by the Police for investigation.  This switch socket outlet, installed outside the bath room,  was connected to the supply using another 3 core cable.  The wiring is an illegal addition according to the local codes which required all fixed wiring (e.g onto the walls) must be carried by licensed electrical worker e.g. an electrician and proper wiring method consisted of conduits or trunking should be used.  No flexible cables should be used.

What can I do if the house does not have an ELCB installed?

The Electricity ACT 1974 mandates the installation of ELCB in all new apartments including HDB flats.  Those built before this date might not have ELCB installed as a standard.  One should install the ELCB immediately for these electrical installation at the main switch panel.  It may cost around SGD $200/= including labour but it will save some life. 
However,  one could also install power socket extension plug with ELCB protection.  In such case,  it is better to check if the power socket extension plug has proper testing certificate from recognised institutions.  This extension plug might not be cheap.

Update:  The Coroner's court 

The Coroner's court in March 2015 found that the boy could have come into contact with an electrically energised metallic shower outlet hose that was attached to a water heater.   The court added that the boy's father installed the water heater about three months earlier. The simple installation work did not fulfil the strict definition of 'electric works' regulated by the Energy Market Authority.

http://www.straitstimes.com/singapore/courts-crime/teenager-electrocuted-in-shower-died-of-misadventure-coroner-finds

27 March 2017

 Installing New Instantaneous Water Heaters


1.  Never trust anyone whosoever install the electric instantaneous water heater for you. Even if it is a qualified electrician or LEW, they might make mistakes.   He may also be color-blind making wrong wirings;

2.  Make sure you see that person who install the water heater test the earthing system in your present. If possible, ask the person to perform a earth leakage test using method just described to ensure that your house's earth leakage circuit break (ELCB) or residue current circuit breaker (RCCB) is working properly;

3.  Also make sure the water heater has PSB/SPRING – Singapore or approved testing label.

Novita Garment Steamer Repair

26 July 2014

Turning on the Garment Steamer one day, it tripped the earth leakage circuit breaker (ELCB), cutting off the electricity to the whole apartment. The steamer is Novita brand and the model is SS23. It was about 14 months old and the warranty has just expired. 

The name plate reading is as shown

What could be wrong?

Immediately, a corroded heater unit came to mind. Water or moisture could have found its way to the heating element, thus causing the short circuiting of the line to the earth and the tripping of the ELCB.

However, after opening up the unit for inspection and testing, it was found that boiler unit was covered up completely with calcium scales inside and outside of the heater unit but the heater unit was found to be in good condition. The moistures soaked up in the calcium scaling could have caused the ELCB to trip.

Opening Up

The unit is attached to lower carriage by about 8 screws. After releasing the 8 screws and opening up, one can see the plastic boiler unit and the heater unit. The boiler unit is held onto the upper case by 4 white screws and the heater unit is held onto the boiler unit by 6 black screws. A silicone gasket at  the rim of the heater unit and the ring bracket provides the water sealing.

In this particular unit, one could see that the base of the boiler is covered by whitish calcium scales. It may be formed by steams releasing through the gasket under the steam pressure. The scales may have been built up on the base of the heater unit over the one year period.

Insulation Testing Before Dismantling and Cleaning

It is good to use a multi-ohm meter to test the insulation resistance of the heater element after clearing and cleaning up all the terminals using industrial thinner or spirits or other suitable solvents. One should get some reading of more than 200 K-ohm before proceeding to strip the boiler unit. Should one get a reading lower than 100K-ohms, it is likely that heater unit could be bad and may require replacement.

In this particular steamer, the heater unit was found to be in good condition except for the calcium scaling at the base which had lowered the insulation resistance.

Removing the Boiler Unit

To clean up the calcium scale and cake completely, one would have to remove the 4 white screws of the boiler unit and all the wirings attached to the thermostat and the heater unit. Note down where and how  each wiring is attached and connected to before dismantling the wirings.

Unscrewing the plastic nuts on the top cover to remove the whole boiler unit. After that, unplug the silicon hose.  After that,  unscrewing the 6 black screws on the heater bracket that holds the heater unit to boiler shell will remove the heater unit completely. Please take care not to damage the silicone gasket which can be re-used.

In this particular steamer, the dome shaped heater unit and its base were completely covered with calcium scale and cake.  

Reasons for Calcium Cake and Scale forming

The use of ordinary tap water which contains a lot of minerals especially  rich in calcium might have cause the built-up of the calcium scales and cakes.

If the water remained in the boiler unit is allowed to dry without draining out after use, calcium scale and/or cake will start to form.  This is true when the calcium concentration in the water exceeded the soluble limit.  Further,  the evaporation of water,  turning water into steam will leave concentrated calcium elements behind in the boiler unit to form the scale.   This calcium scaling or caking is a  common problem in all boiler units.

How to Prevent Calcium Scaling and Caking

Always use soft water that has little or no mineral. If one has air conditioning unit in the apartment, the condensate water will be an ideal soft water for such usage after filtering. Using PUB's Newater is another source; besides,  there are  other drinking water that has been filtered to get rid of most minerals especially calcium carbonate and related calcium products.    Should ordinary tap water be used,  always drain the water completely after use and never leave any water behind to form the scales and cakes.

Cleaning the Heater Unit and the Boiler Shell

The boiler shell is made of plastic. There was no de-scaling required except for removing the calcium cake formed at the shell.

The heat unit on the other hand will require a complete wash down using damped cloth soaked in vinegar, then  brush over with an used tooth brush and thereafter,  flush in the running water.

Avoid using shape and hard object such as a knife to remove the scales except when clearing away the scales at the rim of the heater unit for proper seating and sealing of the silicon gasket.

As running water will be used for cleaning, it may be necessary to masking tape the heat terminals to prevent water seeping into and damage the insulation of the heater.

Assembly

1. Reverse the dismantling procedures except for:

1. Applying silicone grease onto the silicone gasket and “polishing” the base of the boiler with silicone grease  to prevent future scaling taking place;
2. Heating and drying up the heater and the boiler units with a hair dryer, making sure there is no water at the wiring terminals

2.   Measure the insulation resistance between the wiring terminal of heater unit and the metal base,  making sure the insulation resistance is at least 200 K-ohms; if necessary, use hair dryer to dry and chase away the moister in the heater unit.

Starting Up After Repair

Some water moistures or molecules may have found its way into the heater unit if the insulation resistance is less than one mega-ohm.

These moisture will have to be “purged” out; otherwise, it may trip the ELCB again when the unit is turned on for testing.

To “purge” the moisture, use an adaptor without the earthing connection or otherwise, remove the earthing cable temporarily to prevent ELCB from tripping.

Exercise caution not to touch any metal part of the steamer in the absence of the earthing cable as these metal parts may be alive without the earth wire connection.

Fill the steamer with some water, then switch on the steamer.  Let the steamer run  for at least 5 to 10 minutes; thereafter, measure the insulation resistance of the heater unit again using the ohm meter. One should get insulation resistance of more than 1 Mega ohm between the heater element and earth; otherwise, repeat the process.

While draining out any water left in the boiler, make sure to take necessary precaution as the water in the boiler may be very hot.

Schematic Wiring Diagram

Unique Digital Clock with 4 functions

24 July 2014

This unique looking digital clock sold by IKEA Singapore for less than SGD$5/= has 4 functions;  it has a digital clock,  an alarm,  a digital temperature and a digital timer.   It is made in China and called KLOCKIS. 

The Construction and usage 

The clock measured  about 70 mm square and 30 mm thick.  It requires 2 AA size battery for operation.    The current draw is as follows  

Working Display with  LED light off: 7 to 13 uA

With LED light on : 8-15 mA

Alarm : 22 mA 

Therefore,   a set of  battery should last for a few months if it is not often used as an alarm clock. 

The 4 functions are as marked in the clock surface and the functions are selected accordingly when the marked function is at the top.  The LED light will change color  momentarily for each display,  red for clock,   blue for temperature,   green for timer and light blue for alarm. 

The Timer

The Clock

The Temperature

The Alarm Clock

The clock has only 2 setting buttons at the back, one for setting the digital and the other for adjusting the display.  The button only allows forward adjustment.   

The alarm will set off in any display function once it is set.  There is no alarm button to silence the alarm.  The alarm can be silenced by turning the clock from one function to another.  

Conclusion

This clock is useful in the kitchen,  bedroom and in fact anywhere. For SGD4.90,  there will be many satisfied customers.

User Manual

Wyatt card 32L Battery Operated Water Pressure Washer

30 June 2014

This battery-operated car washer was sold for about $45/= including shipping at Q0010.  It is suitable for most water cleaning jobs in cars as well as in homes.   It is a handy pressure cleaner for washing the air-conditioning outdoor units which hand-operated pressure washer just could not do the work properly.  The delivery was the next day which is pretty fast.  

Pros

1. It has a 32-liter water tank;
2. It can deliver up to 1.2 mpa (130 psi) water pressure; Its motor is rated at 3.0 mpa (430 psi)
3. It is potable and equipped with all cleaning accessories,   such as a water brush,  hose,      and water gun;
4. It has auto-start and stops function triggered by pressure sensing
5. It is safer to use as it operates from a 12 volt supply which requires 4 to 5 amperes for normal operation;
6. It is constructed from ABS plastic that can withstand rough usage.

Cons

1. A full tank of water can be quite heavy to be carried around without having a trolley, But one can always carry a half-full tank then fill it full tank with a pail of water. 
2. Water can leak from the bottom of the tank when the suction hose is not properly secured;
3. The manual is written in Chinese.

Compared to hand pump washer

Pros

1. It has a larger water tank;
2. It can deliver at least 6 times the water pressure for cleaner wash;
3. It does not have a pressure tank that can easily crack;

Cons

1. It can be heavy to move due to larger and heavier water tank

Compared to mains operated pressure washer

Pros

1. It is safer to operate using 12 volts supply;
2. It does not require any hose for connection;
3. Can get supply directly from car batteries;
4. Easy storage as it comes with a box 

Cons

1. Refilling of water is required from time to time;
2. Needs 230 volts to 12 volts power adapter for mains operation; 

Construction

The box is quite pleasing in appearance and comes with a toolbox that can store all the components and accessories.  The box can be easily stored away in the storeroom.

The Pump Compartment

Hidden away from view is the pump compartment that is located underneath the water tank.  It can be opened for inspection by removing the 8 screws that held the cover as shown here

The 12-volt motor is held onto the bottom of the tank by a set of 4 screws.   

Testing 

It is noticed that the tank must be almost half full before one can prime the pump to start using the washer. 

When filling up the water,   water started leaking from the bottom of the tank.

 

Why the Water Leak? 

Water was found leaking from the flexible silicone hose that was only  ‘threaded” through the compartment hole without any adaptor or connector. The hose was connected to a non-return strainer located inside the tank.   

The design requires the flexible hose to be properly straightened so that the water seal is maintained by the wall of the flexible hose.  Water can leak through the ‘kink” if the hose is not properly seated to seal the hole as can be seen from this picture.

What Can be done?

Temporary fix

Pull the silicone hose carefully with a light force from the strainer inside the water tank to straighten the hose.  This will make sure that the “kink” on the hose will be straightened out.  However,  as the hose is flexible and can collapse under suction pressure,  the “kink” will soon re-appear after some usage.

Easy Permanent fix 

Cut a piece of a plastic tube with a diameter of around 7mm.  Test if it can easily be inserted into the hole to expand the hose to form a tighter water seal between the compartment hole and the hose as shown.   While testing the correct size of the plastic tube to be inserted,  unleash the hose clamp and pull the hose from inside the tank until one can try to test the fitting of the plastic tube.  Try not to pull the hose out totally as it could be a pain to re-insert the hose again.

While installing the plastic tube,  always make sure that the plastic tube would be larger than the inlet of the water pump so that it would not be sucked into the pump should it become loose during operation. 

Performance  

The washer has a pretty strong water pressure that can even strip off the paint work on a PVC pipe as can be seen from this video.
 

The pump would stop and start automatically just like any electrically operated pressure washer.  It has also a polarity switch that can switch over the polarities automatically without worrying if one has correctly connected the 12-volt cable in the right positive or negative polarities.   

The washing operation is quite smooth although one would have expected the soft suction tube to collapse occasionally when there is not enough water in the tank.  However,  it should not have caused permanent damage to the pump.

Operating from a main operated power adaptor

The washer can be operated from a 12-volt power adaptor which must have an output rating of at least 6 amperes. 

Conclusion 

It is a cost-effective car battery-operated water pressure washer which is well designed except for the leaking flexible suction hose which can be easily fixed.  Other battery-operated water pressure washers would cost easily more than $100/=.