The Sony HR-GP5 is a guitar processor with multiple effects that allow players to layer effects to create unique sounds. While the Sony HR-GP5 processor is laid out fairly simply for consumer use, making repairs on internal circuits should be left to a qualified technician if you are not familiar with working on guitar effects or repairing and soldering on PCB boards. Improper repairs can cause damage to the guitar processor that will cost much more to fix than the original problem would have.
Unplug the HR-GP5 processor from the wall outlet, surge protector or DC power brick on your pedal board. Remove any batteries that are powering the unit as well.
Disconnect audio cabling connected to the inputs and outputs on the HR-GP5. Make a note of where to reconnect the cables after repair.
Unscrew the casing on the top, bottom and sides of the guitar processor with a Phillips-head screwdriver and hex wrench. Do not pull on the casing or use your screwdriver to pry the casing off. Be patient and remove all of the screws holding the unit together before trying to remove the casing.
Make sure all of the cabling on the PCB board is firmly connected to the wiring harness. Don't pull vigorously on cabling, just touch the area gently to make sure the cables are properly connected and have not come loose over time.
Look for damaged or burnt resistors or components on the PCB board, which can cause power failure or intermittent operation. Remove any damaged components with a clean, hot soldering iron.
Procure replacement electronics from an electronics supply shop or online retailer. Make sure it is the same type of component. If you are unsure, take the piece with you and ask a qualified technician that can order the right part for you.
Solder the component in place with a hot soldering iron and solder. Remove any excess solder on the PCB board.
Reassemble the outer casing. Plug the audio cables in and test the unit.
If your Sony HR-GP5 is still under warranty from the manufacturer or retailer from which you purchased the unit, you should not open the casing and attempt to make repairs yourself. This may void your warranty for future problems or if you cannot successfully fix the problem yourself.