Uniden Phone Power Supply Repaired
This story is about a wireless UNIDEN (VietNam made) phone and the complaint was the phone never switched on, and therefore, the owner could not use it.First thing done was to disassemble the Power Supply Unit (PSU) which had the following features:
- Output: AC 8 volts.
- 300 mA.
The photo below shows the base of the phone.
The PSU was disassembled. Once it was in my hands the continuity of the primary winding of the transformer was checked with a Digital Multimeter. There was no continuity, now I had a clue to continue my job.
I had an idea which has saved to me in many occasions: to break the isolation ribbon (blue colour in this case) of the primary winding of the transformer. Why? Because in a great deal of cases the manufacturers hide a fuse in this place, look at the photo below.
As you can see in the photo above the fuse was hidden under the isolation of the primary winding. The fuse was tested with the Digital Multimeter and it was open. Therefore it was substituted for a similar one. The PSU was connected into the AC outlet of the wall and there was AC out in the secondary winding. The PSU was assembled again and connected to the phone.
The DC-out of the base was tested and it was fine, look at the photo below.
The wireless phone could be connected to its base now.
The owner was very happy because he could use his wireless phone again. Mission accomplished.
This article was prepared for you by Humberto Rodriguez, one of our ‘Master Authors’ from Cuba.
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Robert Calk
February 9, 2015 at 12:56 am
Good job Humberto. When I fixed my sons' fan that had a bad thermal fuse on the motor, I bought a bunch of them in various temps to have on hand the next time I need one.
Humberto
February 10, 2015 at 9:23 pm
Thanks Robert
Amir Mukhtar
February 9, 2015 at 2:35 pm
Mr. Humberto Rodriguez Thanks you for your Nice Article.
Mostly, ITE Adapters having Thermal fuse inside the Tape Insulation, Which saving amount to Re-wind transformers.
Good Job and Keep sharing expertise with us.
Thanks you
Amir MUkhtar AShrafi
Humberto
February 10, 2015 at 9:24 pm
Hi Amir, you are welcome
Mark Tembo
February 13, 2015 at 10:30 pm
Smart job indeed! thanks.
Humberto
February 16, 2015 at 10:33 pm
Thanks Mark Tembo