Close
0%
0%

Onkyo M-508 Repair

Restoring an imposingly beautiful 500W/Channel Power Amplifier

TedTed
Similar projects worth following


The Onkyo M-508 is undoubtedly one of the coolest looking power amplifiers out there.

Giant needles of watt-o-meter.. imposing heavy as lead stance on the shelf. Everything about this amplifier says "turn the volume down before you hit the power." It has impressive THD specs and pumps 200WRMS and 500W peak into 8ohms each channel!

Unfortunately, the engineers who did the PCB layout were obviously working for corporate penny pinchers. To save some trace, they used 4-terminal power capacitors (unkeyed) and used one in particular to make a jumper connection on the 1 layer PCB.

At very high power, over the course of many years of dedicated neighborhood irritation, this cap would heatup due to the copper loss through the connection.

Eventually it burst, and spewed yummy electrolyte all over the board. And so begins a multi-state multi-decade saga of repair.

Enjoy this project?

Share

Discussions

AZYON wrote 08/06/2018 at 16:27 point

Did you finish working on this guy? Just got a mint 508 myself, with woodpanels and all. 75USD, lol. Thinking of re-capping it and stuff, so wouldn't mind a log if you had one:)

  Are you sure? yes | no

Ted wrote 02/05/2015 at 14:26 point

I had it running over the weekend. Also blew it to bits again. Build log is coming soon

  Are you sure? yes | no

Similar Projects

Does this project spark your interest?

Become a member to follow this project and never miss any updates