I recently purchased an MXR '74 Vintage Phase 90, but it had a couple of problems when I received it. First, the back plate bulged outward in the middle. I took it off, placed one end on a piece of wood and kneeled on it until it was straight. When I placed it back on the pedal, it was a very tight fit, but the bulge was gone. However, when I tried the pedal, it didn't work. The pedal sounded normal off, but when it was engaged, there was no phase effect. It sounded like a slightly muffled version of the clean signal. I removed the backplate, checked the battery, and looked around inside for anything obvious, but did not see anything. I tried it again before putting the cover back on, and the pedal worked fine.
Based on that, I assumed that two things that shouldn't touch were touching. The only thing I saw that could be doing that was the lug on the output jack that carries the signal. It was pointed up about 60 to 70 degrees, I would guess (about where the red line is in the photo below). I think this could have been touching a solder point on the bottom of the circuit board through the foam when the cover was on. I bent it down (gently), replaced the cover, and it has worked consistently ever since.
Based on that, I assumed that two things that shouldn't touch were touching. The only thing I saw that could be doing that was the lug on the output jack that carries the signal. It was pointed up about 60 to 70 degrees, I would guess (about where the red line is in the photo below). I think this could have been touching a solder point on the bottom of the circuit board through the foam when the cover was on. I bent it down (gently), replaced the cover, and it has worked consistently ever since.
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| Original position of lug is indicated by the red line. I bent it down to its current position. |
Anyone have any similar experiences with the '74 Vintage Phase 90?
