All checked out on headphones, great sound, all 4 channels working fine. I changed all the bulbs for leds, that's 9 fuse lamps, 12 indicator bulbs and even the 2 in 2/4 channel display (that was really fiddly). By the way, the fuse lamps were working off 10v so I used standard 12v ones that are sold for car courtesy lights and they work perfectly - just the right brightness. Now I was ready to check it with speakers so first I checked the voltage on the speaker terminals - on stereo it was a perfect .02v on L and R front but showed .75v on the both rear channels. When I switched to 4 channel... suddenly it became .75v, on both front L & R and also rear L & R. I'm guessing there is something wrong with the amplifier for the rear channels. Does that sound reasonable? I checked the power transistors but they don't show any shorts...... Any suggestions welcomed. Photo attached.