Monday, November 27, 2017

14 Inch China Television picture height low

I got a phone call from a client who wanted his television checked, I visited the place and was shown the television and when switched on I noted the picture was only present from the center of the screen to the bottom and also some retrace lines at the bottom.

Usually whenever you see the screen is not full vertically means there is some problem with the vertical circuit meaning it is not doing its work of opening the screen vertically.

Since the owner wanted the TV back urgently he decided to accompany me to my workshop and once on the bench I opened the set and went straight to the vertical circuit.



Since there was something on the screen I did not suspect the vertical I.C and my concentration was on filter capacitor on that circuit...

Remember the retraces lines? This also lead me to suspect a failed capacitor on the same circuit and therefore the first thing I did after opening the set was to scan all the electrolytic capacitors around the vertical circuit and I was not able to pick any with top swollen and therefore I had to use the next method of testing capacitors using my ESR meter.

After a few tests I was able to bump on a capacitor C563 (220uF/35V) which read open according to my ESR meter which has maximum ESR range of 100 Ohms.


At first I could not believe that this capacitor was faulty since looking at it look very innocent and therefore I had to solder it out of the circuit and re-test again.

After doing out of the circuit test I also got the same result (OL) out of range and with this I concluded the capacitor was completely dead.

Sometimes I do sympathizes with techs who don’t invest in ESR meter/Mk-328 multicomponent tester since most of the business pass them due to lack of proper gadget of testing capacitors which are the main cause of many failures in electronics equipment.


After picking this capacitor I replaced with another rated 220uF/50V which I had in my capacitor kit which I always buy to minimize going to the shop every time I need one.

After replacing the capacitor it was not time to do the testing and after applying the power I was happy to note the screen was now full.

The whole process took me let than twenty minutes and since the owner was there I has problem with charges since he thought I have done very little for the charges I quoted but I explained to him that in repair what is important is getting to know where the problem is and that is what we charge for.

I am sure if this set was taken to a tech without ESR meter it would have ended up in the dust bin which could have been more expensive to the owner.
Thank you guys.
See you in the next class


7 comments:

  1. Excellent Job. I already purchased mesr-100 from ebay in 65$. It is the best among all. Love to use it.

    ReplyDelete
    Replies
    1. Thanks for your feedback. regarding the ESR meter....TELL THEM IN CAPITAL LETTER

      Regards Humphrey

      Delete
  2. You are absolutely right.. the ESR is a vital kit to have..

    ReplyDelete
    Replies
    1. Yes! TELL THEM IN CAPITAL LETTERS hahaha

      Regards Humphrey

      Delete
  3. Thanks Humphrey for this vital information. Iam actually faced with a related problem but for this one the screen displays half way but from the middle upwards. could it still be a capacitor failure?

    ReplyDelete