QYT KT8900 has good form factor that fits in the palm of your hand. It’s a dual band radio 2m/70cm that supports dual frequency monitoring has an acceptable receiver capability for the price, good audio performance (loud and crispy). Supports FM radio broadcast listening moreover it has a built in repeater function that will work in combination of another QYT KT8900 or pair it with QYT KT8900D by just enabling the function on the menu system and adding a repeater interface cable which can be built easily with spare LAN cable, RJ45 connectors and crimping tool.
If it’s not for the faulty heat sinking then probably this radio will work longer than expected rather than giving up the magic smoke of the RF finals too soon.
Preparing the RF finals removal and replacement
Disassembling the radio to replace the broken RF finals reveals that the screw holding the heat sink is loose just secured by a piece of copper strip inserted to the metal spacer to float the heat sink above the RF finals.
The radio board showing the QYT RF finals
Replacing the RF finals is moderately easy provided you have the right tools a hot air rework station, solder flux, a pair of tweezers. The radio board backside reveals a slightly bigger heat sink which probably is intended to absorbed the heat more effectively by coupling it on the radio chassis, but without using a heat sink compound this also is not too effective to properly address the heat issue.
Time to replace the RF finals, apply the solder flux on the chip, heat the board just enough for the solder to melt at the bottom of the RF finals, remember that this is also attached to a copper heat sink below so heating it will take a little longer before you can see that a solder is flowing on the side of the finals. Once removed successfully replaced the finals with a new one. Good news for people living in the Philippines, the RF finals is now available by visiting your favorite electronics store in Gonzalo Puyat street in Sta. Cruz Manila price varies depending on the stores.
Preparing the fan modification on the radio chassis
Attaching the fan on the radio chassis requires a bit of drilling and tapping to hold the fan securely at the back of the chassis. For QYT KT8900 you can see at the back of the chassis that they somewhat prepared a fan mounting holes, but they didn’t pushed through with the plan. On later versions of this radio a fan is now attached to help in cooling the radio.
Drilling the fan mounting hole with a drill step bit.
Preparing the screws holder by tapping a thread.
Putting it back together.
Finally the finished modification applied to the radio.
The final look and successful cooling fan modification.