Thursday, May 23, 2019

PANASONIC RADIO MODEL RX-CT840 DEAD NOW REPAIRED


A customer brought in this radio and wanted it to be repaired; he estimated the radio to be around 20 years old.


Since the radio was dead the best place to start troubleshooting was the power supply, the radio was using linear transformer to step down the 240 Vac to 9 Vac.

Wednesday, May 1, 2019

21 inch CRT WEGA television take long to power up-screen narrow vertically



I received a message from my neighbor who was not in town to go check out on his television which was reported faulty by his family members since he works out of town.

I passed by in the morning and was shown the television which was left on overnight by the kids but I could see from the screen that the vertical height was collapsed.

The image was narrow vertically; the picture was just 3 inches high.

I inquired how the problem started and they told me the problem started by the television taking too long for the picture to appear on the screen.

Wednesday, April 24, 2019

21 Inch JCV CRT television vertical closed now repaired


A customer brought in a JCV CRT television for repair, kindly note the model is JCV and not JVC and therefore the television can be classified into the cheap China made television which comes with all manner of names.

That is why as a customer you should be careful when buying electronics equipment because many come with names very close to the branded machines (buyers beware).

Monday, April 15, 2019

Sanyo LCD television model 24K40 dead power On LED Red


I received this 24 inch LCD television from a customer who wanted it to be checked.
Symptoms: Television is dead but the power on LED is on and RED in  color like the television is on standby mode.

I tried pressing all front keys and no change, then I decided to open the set for  further testing, once the television was open I scanned the power board with naked eyes looking for any suspicious components  and everything looked good.

VITRON LED TELEVISION MODEL HTC3228 AUDIO PRESENT BUT NO PICTURE NOW REPAIRED



I received this television from my neighbor and the complaint was sound is okay but no picture symptoms.

First I had to confirm if what the client is saying is correct and after switching on the television indeed the symptoms were confirmed right.
I took the set to my workshop and before embarking on opening the set I decided to use a bright light from the torch to see if there is something on the screen like dark picture which will guide me exactly which circuit to suspect even before opening the set.

Wednesday, February 20, 2019

LCD-LED television repair guide

Introducing my new e-book

LCD - LED television repair guide




Dear electronic repairer,

LCD- LED television has been around for some times now and seems like the world trend is geared toward that end.

For the technician this means one need to upgrade his software (studies) so that he/ she is not phased out by the new technology.

I have no doubt the reason you are reading this page is because you want to do software upgrade as far as LCD-LED television repair is concerned...Congratulations my friend!

Thursday, January 10, 2019

Startimes decorder hit by power surge


I received a phone call from my neighbor to pass by his place to check on his decoder which he believed was hit by power surge.

I passed by and the decoder was brought to me but since I had no tools to open it up I decided to take it with me to my workshop.
Once on my workbench I opened it and I scanned the board (power and main board) and I could not see any suspect component.

They all looked very innocent, I pulled my meter and tested across the main fuse and found it open. Fuses rarely die of old age, there must a reason why and in most cases they die when there is a short on the supply and therefore I started testing components on the power supply which are directly connected to the main power line.

So I decided to start with the rectifier diodes and I found one which was shorted and this put a smile on my face, this must be an easy fix!


After replacing the diode and the fuse and applied the power using the series bulb current limiter (you can make one easily on this link), I noted the bulb was bright throughout.

With this I concluded there are still shorted component(s) I did not pick, I continued checking and I could not get any other component and this caused me some stress because I had marked this assignment as simple.

I removed the diodes one leg from the circuit one by one and applying the power via the series bulb and once I removed the last diode I noted the bulb was now dim (off) and I realized the diode was failing under load since I was not able to pick it using the meter.

That is why when you find one diode is shorted, it is advisable to replace the four diodes otherwise the chances of the customers calling back with the same problem is high.

  
I replaced all the four diodes and after applying the power via the series bulb, the bulb was bright and then dim and with this I concluded no more shorted components in the supply.

I connected the power board back to the main board and the decoder worked like a charm.
Thank you friends

See you in the next class