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.



I tested the input of the transformer and I got 240 Vac, but testing the output I got zero volts. With this I concluded the transformer is faulty.

I pulled my 12 DC adjustable power adapter and injected the 9 volts dc directly to the power out from the transformer to the circuit and the radio came back to life and with that I concluded there is no other problem with the circuit and therefore once  I sort out the power problem I will be good to go.
See the video below.


Next now is to sort the issue of the fried transformer and being custom made by the Panasonic Company it was hard to get the replacement part.

I checked on eBay and found a second hand one which was going for $20, but before going that route I decided to buy a normal transformer which are easily available in my market and do some modification to the power board.

When buying the ordinary transformer kindly pay attention to the size so that it will fit well inside the radio where the other was originally.
I went in town and got one and came back to my shop and did some modification and power was up again.

 I installed the power back into the radio and the radio was back to normal.

Thank you friends
See you in the next class

4 comments:

  1. Thanks for the lesson. Well done. Good thinking. Many are times when we diagnose one problem and sit back waiting for the spare to arrive only to learn that the set had other issues. Time wasted when you could have fully diagnosed it earlier.

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    Replies
    1. Well put and thanks for your feedback

      Regards Humphrey

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  2. A very good lesson. I have learnt that it's a good idea to check if what you found to be the problem is the only one stopping the set from operating

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    Replies
    1. You are right, thank you for your feedback.

      Regards Humphrey

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