Meet an electronics repairer in Nairobi Kenya

A few days ago I received a phone call from a gentleman who introduced himself as a Technician Based at Ngara market in Nairobi Kenya who came across my blog via the internet and wanted  to meet together for a chat.

So due to my busy schedule we arranged we can meet last Saturday the 25^th June 2011, Saturdays are especially convenient to me because it’s when I normally go to the electronics shops in Town to replenish my spare stocks and I figured out that I can multi task(combine the two assignments).

So after buying the spares I went to check up with him and we meet as agreed, he gave me a brief background about himself and his repair works and I  was surprised to learn that he has has been in this business for over 30 years.

So I asked him what keep him going and he answered in one word “passion” in electronics that keep him going, also to keep him up to date with the technology he uses the internet to search for relevant information, and never stop learning.

I asked him how he promotes his business and he told me that most of his customers come to his business through referrals from other satisfied customers.

Below are some of the photos of his workshop.

Later I proceeded to the outskirts of Nairobi to attend a wedding ceremony of one of my colleague and here are some photos of the occasion.

Make your own ESR meter

After given an opportunity by Jestine Yong to write an article for his ERG members for June-2011 monthly newsletter I have received several emails like the one here below from Happymore Bunu from Zimbabwe.

 Hi Mr Humphrey.

My name is Happymore Bunu.I am a qualified electronics technician from

a popular college in Africa (Mutare Poly ,Zimbabwe).I finished my 3

year course in 2005,then graduated in 2006.I worked for many

companies, but finally I am now having my own workshop in Mutare.

So this is my second year, with my workshop. I got to know you through

Mr Jestine.I am a subscriber to Mr Jestine. I really liked your post of

2010, building your own ESR. I want to build this project, but I am

facing a problem with the component values. I am struggling to read the

values. May you sent me a circuit diagram of this project, or any other

solution.

Thank you very much, have a blessed day, bye.

Please note that the above issue of main ESR circuit values were revised by Mr Yong.

He has also included a PDF version of the same for easy printing.

http://www.electronicrepairguide.com/build-your-own-esr-meter.html

Wishing you all the best

Humphrey Kimathi

The important of checking errors done in the previous repair

On your line of duty as a technician sometimes you will receive equipment brought to you which have gone through another technician and was not able to repair due to lack of spare parts or he/she did not have what it takes to sort out that problem.

As a technician it is very important first to scan the whole board noting down any component which seem to have replaced and confirm indeed it was replaced with the same (exact) component.

The reason I am saying this is because sometimes most of the spare part Shop attendant don’t have good knowledge in electronics components and therefore if they find that they don’t have the exact component they usually suggest to you an equivalent which according to them they think can work but when you look up for this component datasheet you will find that even they are not related.

I had this experience one time I received a Television motherboard from a friend who lives upcountry and I decided to make a try because according to him all technicians from his home town were not able to repair his Television.

I scanned the primary power supply section and noted there was a replacement done on the switching transistor (S.O.T) but I didn’t bother to confirm if it is the exact replacement and so I continued to troubleshoot the board.

I tested all the components on the primary side and they all tested okay according to my meter but still the power supply was not starting, the voltage was reaching the switching transistor collector pin and there was also voltage at the base of this transistor but still nothing is happening.

So I decided to check on the internet the Specification of this new installed transistor “ D2499” and this was the specification” Horizontal deflection output for color Television”

So it means even if I found this transistor was once again faulty and change it with the same new one still I would not have repaired this set, so I replaced this transistor with “D1710C” and the Television started but shutdown immediately(I could hear the relay click)

When I used the dummy load (60 Watt) bulb on the B+ line I noted the bulb came up with intense light. I noted the Television was having the B+ adjust Pre-set and adjusted it slowly and I powered on again and this time the dummy load bulb was well lit and I was able to measure the B+ voltage and set it to 110 Volts according to the working B+ voltage of that Tv.

From that day I leant the hard way the important of confirming first whatever replacement done previously are actually okay and meet the specification required for that circuit.

Another common mistake is replacing the secondary diodes with ordinary diode, please note that the secondary diode are fast switching and therefore cannot be replaced with the ordinary 1Nxxxx series.

With that thank you guys

See you in the next class

Humphrey Kimathi

Author CRT television repair course.

Electronics repair spare parts source

I received this email in my inbox from one of my Customer of CRT Television repair course book.

First I thought he was coming back to me for some support but when I went through the email I noticed one concern which could be facing many Technicians out there….

The problem of spare parts…I mean you have done your best in troubleshooting and narrowed the problem to the component level and you start celebrating for the job well done only to turn to your local electronics store and find the spare part is not in the market.

You find you have wasted your time in troubleshooting and incurred some expenses traveling to the electronics shop…I my self I have experienced this several times especially when sourcing for the snubber capacitors here in Kenya…they are never stocked here..this Capacitor also known as safety capacitor is one of the main killer of the HOT transistor and therefore as a technician it is advisable to replace this Capacitor every time you replace the H.O.T  without even testing it otherwise you risk call back in less than 48 hours.

Most of the time if you salvage it from the junk most likely it was the cause why this board went to the Dust bin. The last time I went to buy this Capacitor the shop attendant told me they don’t stock them.

I went further and asked him why and he answered me that Technicians never ask them.

So I hope you techns out there you need to start asking for these things so that these guys can get an idea they are important for us to be in the market.

Luckily with me I have a friend Mr Beh all the way from Iran who send me some 20  Pieces of Snubber and a packet of Iranian Nuts(AJAAL) the latter is not spare part so i send them straight where they were supposed to go  and as at now I am not complaining but what about my fellow thousands of Techs out there without plan B.

For this Cause I am calling on board all technicians out there if you have a problem with spare part we can network among ourselves and maybe the spare part you are looking for is at your next door(Country) and you can easily get it.

For me I can assist by publishing the most wanted spares on my blog and lets technician out there come on board and see how we can help each other..

let us please minimize the number of electronics equipment going to the grave early due to lack of spare parts.

Any comment on  this is highly welcomed from my fellow techs.

Humphrey Kimathi

Author CRT Television repair course.

How to access the CRT neck board of CRT monitor

CRT monitor and CRT Television have a lot in common in terms of Circuit working and hence one can easily use the knowledge in CRT television to repair CRT monitor.

The first time you open up a CRT monitor can be quite a challenge because components are quite congested than in the Television.

As a technician this should not discourage you because after all it was assembled by a man/woman like you. Of particular interest is the small CRT neck board in monitors because it is fairly shielded and therefore to access the small board can be quite a challenge for the first time.

In this article I am going to point out some few things you should do to access this board if you need arises like when the CRT monitor has color problems like the one shown below.

If you are in Television/monitor repair you can narrow down to the faulty circuit if you understand circuit functions by just watching the screen even before opening the set.

On the case at hand we have the screen with color problem. The screen is covered fully and therefore we can conclude that the Power supply, horizontal circuits, vertical circuit, the fly back transformer are all working well and should not be considered for repair.

So the best place to start out troubleshooting is the small CRT neck board, therefore we can now open the set and go straight to test our hypothesis (please make it a habit to take time to make proper diagnosis from the visual and audio clues even before you open up a Television or Monitor, it will really save your time)

When opening up any equipment for the first time it good also to take note where connectors are attached so that you won’t have problem when reassembling, basically reassembling is the opposite of assembling so you will be reversing what you did when re-assembling. After opening a few set everything will become auto.

With that here we go….The inside of CRT monitor

As you can in the photo above the CRT circuit board in monitors is shielded and therefore in order to access the CRT neck board which is our mission we have to open up the cage. First we have the connectors and these you can easily remove them from the connection points by hand because they are not soldered, next you will find some connection between the CRT neck board and the shield which is actually soldered and here you will need to use your hot gun to solder it out.

If you have removed all the connections then you should be able to remove the shield pretty easily but if you find that it still becoming hard to remove then probably there is still a connection which has not been disconnected. Look for it carefully because if you force it out you may do some damage to the circuit.

After you have removed the shield then normal troubleshooting should continue without any cause for alarm.

Wishing you all the best

Humphrey Kimathi