How to repair Panasonic RF 4800 (digital frequency readout and lighting)

[ektpuah]

My Panasonic RF4800 was working perfectly until today when I attempted to put in LED lighting to the dials and S-meter. In the process, I shorted the lighting and the left dial light fail to light up. Checked the voltage on the wire, no voltage. Then, due to my stupidity , I pulled the plug CP15, there goes the digital frequency readout and all dial lights and the S-meter light .I though I heard a soft pop and a bit of smoke!

I am totally upset and would appreciate some advice as to which component I have burnt in the process.

Many thanks and best regards
James Puah
9V1JP

 

[Resqueline]

It seems you can download a service manual here. You only have to register.

 

[ektpuah]

It seems you can download a service manual here. You only have to register.

Got the service manual, now hoping that someone with similar experience would share their repair experience to help me quickly pinpoint the faulty component..

 

[ektpuah]

Got the service manual, now hoping that someone with similar experience would share their repair experience to help me quickly pinpoint the faulty component..

I managed to trace the source of the problem to a burnout 12v PCB copper trace and a burntout diode. Also managed to replace a number of transistors (mainly in the amplifier pcb and also a switching transistor on one of the main board. Now the frequency display and dial lights are back to normal. Looks pretty impressive, I'll try to take a picture and post it here later.

 

[Resqueline]

Hey, congrat's on a successful repair! And even before I got around to helping you!
Thanks for reporting back, and please do post pic's of what happened.

 

[ektpuah]

I managed to trace the source of the problem to a burnout 12v PCB copper trace and a burntout diode. Also managed to replace a number of transistors (mainly in the amplifier pcb and also a switching transistor on one of the main board. Now the frequency display and dial lights are back to normal. Looks pretty impressive, I'll try to take a picture and post it here later.

As promised, below are some pictures (apologise for the not so clear image)

 

[Ian]

Thanks for reporting back with the fix ektpuah, that will be a huge help to anyone else with the same problem

 

[ektpuah]

Thanks for reporting back with the fix ektpuah, that will be a huge help to anyone else with the same problem

Yes, I hope that this will be of help to anyone having similar problem. One thing I forgot to mention: I applied superglue sparingly to the red wire to shape it as closely to the original PCB trace as possible. There are better ways to repair this like getting the PCB repair kit with thin copper sheets and glue to glue the copper to the board but I was too tired and too eager to get this radio up and running and took the short cut. Could have done a more professional repair job.

James Puah
9V1JP

 

[Resqueline]

That's a good job in my book. Most people would've just put the wire straight across.. Nice rig btw..

 

[servicio.tecnico2200]

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