Onkyo M-504 Power Amplifier Repair And Restoration

This Onkyo M-504 solid state power amplifier is in pretty good cosmetic shape but needs some repair and restoration.

The Onkyo M-504 power amplifier is well built and laid out nicely.  

With the faceplate removed we can clean the chassis. 

One issue with this onkyo amplifier is that two of the bulbs that light the meter's are missing in action

The lamps were easy to obtain but I didn't have the green gel boot that was on the original lamp. I obtained some green lighting gel.

I rolled the sheet of lighting gel around the lamp and used adhesive to keep it together. This is made for high temperatures.

 It may not be perfect but this Onkyo M-504 Amplifier is glowing a lot closer to it's original green.

Here are all four lamps installed with two original gels and two gels that were made from lighting gels used in stage lights   

Removed the bottom cover and cleaned a few years of dust and washed the bottom panel with soap and water.

A little bit of bench testing and this Onyko M-504 solid state power amplifier restoration will be complete.

This Onyko M-504 seems fine on the bench and is ready for some music. This repair and restoration is complete.