MEG.XL TV No Sound Repaired
This MEG.XL CRT TV came in for repair with the complaint of no sound. Even though I had adjusted the volume to 39, there was still no sound. No sound symptom can be cause by many factors such as bad sound IC, no DC supply to sound IC, bad speakers, dry joints in the audio circuits, corrupted EEPROM IC and etc.
The first thing I did after opening up the cover was to clean away the dust in the circuit board. I got to use a brush and vacuum cleaner for this purpose. If you have air blower, you can blow away the dust in an open area.
Next is to use visual inspection to scout around the circuit board (front and back) for dry joints, loosen wires/cables, components and etc. In the below two photos, I actually found two ICs that had some dry joints.
The most obvious one was the sound IC. You got to use magnifier glass to look at the joints.
I did not check the sound IC DC supply before turning it On because I had confident it will work after applying fresh solder onto the IC pins/leads. True enough, once the power was On, the sound came back normally.
Conclusion- Assuming after applying the fresh solder to the sound IC and also to the corresponding IC and still no sound, I will have to check on the DC supply voltage with power On. If the DC supply is good I may have to suspect the EEprom fault (corrupted firmware). You can read my previous repair article about no sound problem that was caused by a corrupted EEPROM data here.
This article was prepared for you by Suranga Bandara who owns an Electronics repair shop in Anuradapura, Sri Lanka.
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Albert van Bemmelen
February 3, 2021 at 1:29 pm
Good and easy fix! Cold solder joints are like bad e-caps the main concern in most repairs. The fact that the solder material changed to lead-free silver makes it harder to recognize bad solder joints. And lead-free solder beside tin may also contain other metals like copper, silver, bismuth, indium, and zinc which substance may change in the solder of most bga mounted chips also to lower the solder melting point.
Yogesh Panchal
February 3, 2021 at 6:36 pm
Good FIX! Suranga
cheap solder wire will eat up our solder iron bit as they are using cheap flux in the wire because of that solder neither stuck on the tip of bit nor transfer the heat on the object end result is you damage the trace of the PCB therefore you have to clean your soldering iron bit more often.
If solder wire is Good it does not required extra flux.
Parasuraman S
February 3, 2021 at 6:56 pm
Your experience and the resultant intuition helps you solve problems very easily! Many thanks for sharing!
Gregory Brettell
February 6, 2021 at 7:59 am
I wonder how this unit ever worked (when it was new) with such bad soldering ... good job repairing this.