Tuesday, December 13, 2016

Customer support-Mangala from Sri Lanka

Mangala Wijetilake from Sri Lanka

Hi Humphrey,
On these days I am reading your E-book on Troubleshooting of TVs.  It is very interesting and several questions have arisen in my mind when reading.
It is very much appreciated if you could reply to following questions.

1. There were some tests which have been carried out by dummy load (250 V bulb). How do i decide the wattage of the bulb. Does it depend on the wattage of the TV set?

No really Mangala, you can even use 40 watts, usually it is not wise to dis-connect the B+ line and test it without the load but if you don’t have the load in place then you can test briefly to check the presence of voltage once the B+ load is isolated.

If you isolate the load and apply power and find the B+ has voltage and stable then you can conclude that the primary side is okay and no need of checking it.

Suffice to say here that this is done when you tested the B+ voltage and find it missing and when you dis-connect it you find the B+ voltage now re-appears.
  


Wednesday, December 7, 2016

14” inch China Television with high output voltage now repaired

This television was brought in for repair by my neighbor, upon opening the television I started troubleshooting using the free tools of the trade (my eyes)

I scanned around the whole circuit looking for any swollen capacitor or burnt areas which is usually suspect or signs of stress in electronics gadget.

I noticed a swollen capacitor on the secondary side of the S.M.P.S (C562). Swollen capacitors are usually caused by high voltage on that line and therefore I wanted to find out which line is the capacitor filtering.