Here’s another Boss DD-3. The pedal gives signal in bypass, with effect engaged there’s just dry sound.
Someone has done some repair to the circuitboards power section seen in the upper left on this image.
The Mode selector rotary switch out of the chassie for replacement.
Old vs new rotary switch.
So what’s wrong with it. Found that C34 was broken, it did not pass any signal to the expander circuit. Had it replaced and got the delayed signal through the circuit, though at to high level and distorted. C31 was the cause of that problem. With C31 replaced the pedal works as it should. The tantalum capacitors C32 and C33 was also swapped with new ones as they do tend to fail in time. Checked and adjusted the high and low end of the Master clock frequency.
A rare piece of non functional equipment, a Nadine’s Distortion on the workbench.
Gut shot, the circuit board in nice condition.
The 6552 opamp was burnt, once replaced the pedal’s rocking again. Image of the circuit board with a socketed RC4558 as replacement for the 6552, the old electrolytic capacitors changed and a new battery clip installed.
Checked the switch for D.TIME due to the problem of changing from 200mS to 800mS of delay. Found it’s not the cause. Had the wiring from the switch resoldered and it’s hey, it’s back in normal operation! Also fixed the knob for E.LEVEL wich was glued in place.
Got two Rats of different generations on the bench for repair. The v2 to the left, not working at all. The other one did not reach unity gain.
I had to replace a malfunctioning jfet source follower on the output stage on the old Rat.
The other one had already been messed with. There were several copper traces on the circuit board that had to be mended, the opamp was burnt and wires not connected. Managed to bring it back to life again.