This is the fourth part of the Bang & Olufsen Beolab Penta restoration. For the original post, see:
Both amps were completely inoperable. Most of the capacitors were bad, all power transistors were blown, and various other parts needed replacing as well. I unfortunately didn’t take as many pictures of this process as the 100+ degree temperatures of the Texas summer and the lack of A/C in my workshop led me to neglect taking photographs.
Melted and cracked resistors:
More pictures of the burned resistors in the power stage:
Solder completely melted off from the molten-hot fried transistors:
Expanded and exploding large capacitors:
Fabricating a new fuse box:
Three rebuilt amplifiers! Where did the third one come from? I actually found another blown amp on eBay so I bought it and fixed it as well for a spare.
Rebuilding the control boards for the LED screen: