A friend had a radio alarm clock which was purchased in 1998. Although it was working perfectly well the liquid crystal display was becoming more difficult to see as so much dust had gotten in behind the front cover. She was going to dispose of the radio and buy a new one! I said i would have a look at it and see if it could be refurbished and get a good few more years life out of it.
This picture shows the radio alarm before i started work. The external unit was scruffy and had alot of dust on it but there was very little damage to the plastic casings. I could see that there was a gap between the top casing and the plastic panel covering the LCD inside. This was clearly where the dust was getting in.
This photograph shows a close up of the LCD unit. It is easy to see why it was getting difficult to read it.
Double sided sticky tape was applied to the top case. It was trimmed to the correct shape using a craft knife. The opening was cut out and trimmed in the same way. Here the sticky tape can be seen with the protective cover still in place.
I removed the four screws holding the case together and opened it up. The internal construction was fairly typical of consumer electronic products at the time. There was quite a bit of dust in the bottom half of the case around the LCD so this was cleaned out. A vacuum cleaner was used to remove the dust from the rest of the case.
Here the plastic display cover has been removed from the top cover. It was secured using double sided sticky tape. This was removed from the case and the rear of the display cover. Both areas were thoroughly cleaned and de-greased. Note how the tape does not surround all of the display opening so there would always be gaps that would allow dust to enter.
The protective cover of the double sided sticky tape was removed and the display cover carefully positioned using its locating tabs. The display cover was them firmly pressed into place. The top cover was then secured in place and the radio tested.
The repair of this unit took less than an hour including cleaning the casings to remove dust and finger marks. The cost of a similar specification replacement unit would be GBP25 so it was well worth taking the time to repair it rather than it ending up at the recycling yard or worse still in a landfill site.