Boss 1978 PH-1 phaser. Got this one in a trade some time ago. It was defect, and the guy I got it from had no idea what happend to it, he had bought it that way. I popped it open as soon as I got it. Things were looking good..no burned parts or anything obviuos. It passed signal, but there was no phasing to be heard. I snaped a pic and put it aside for a while. I recently decided to try and fix it so I put a simple audio probe together and started to probe the signal path of the circuit. I quickly found the spot where the problem seemed to be. One of quad chips was acting stramge. Took some measurements and the readings only made me more sure about the chip. I desoldered it and popped in a socket and a TL074. Now, when I searched the same spot with the audio probe things seemed promising. The two chips were now interacting nicely with each other and passing signal.
So, I hooked it up to my zoom recorder and hit the circuit with a drum loop, tweaked the internal trimmer a little and...BINGO! It works! Nice swooshy phaser! A bad chip, huh. I replaced the other working chip with a socket and a TL074 aswell. The working chip(RC3403ADB) I replaced will go into a OD-1 clone later on. Score! While at it I replaced all the electro caps with some new fresh ones.The pedal may not be worth as much as an all original one, but damn, it sound nice...! The battery clip, knobs, and screw ain`t original so I`ll just enjoy it as is. I may mod it some later, but right now I just want to play it. The older Boss pedals need a ACA 12volt dc adapter so that`s not too convenient now a days. The status LED also only lights up briefly as you hit the stomp. The old boss pedals started out this way to save battery, but people wanted a "permanent" indicator while the pedal was active. Boss later on changed this.
Sorry, no after pic of the pcb. Got so exited about boxing it up and playing it! Swooooosh....
