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Hello, My name is kenny tompkins. i have a problem with my fender bassman amp that no tech in my area can figure out. i was hoping to run this by you and see if you've ever encountered this problem before. The Problem is: the amp sat in storage for about 4 years in reasonable condidtions. The power chord was lost during this time. when i got it out of storage, i bought a new power chord at staples, it was made for computers but fit the chord jack perfectly. when i plugged it in and turned it on , it sounded as good as the day i bought it. i played for about 20 minutes and then the problem appeared. All of the sudden, the amp seemed to grab the guitar signal and pitch bend it toward the top register. much like a car engine slowly rising in rpms. its a hard sound to describe. i turned off the amp and checked all chords. turned it back on and it worked again. this time it took about 30 seconds for the problem to appear. the "sudden pitch bender" thing happened. I thought it might be due to the new power chord but could not find info on this subject. i also thought it might be a heat related issue because it took a few minutes to happen when first turned on. Do you have any advice on this topic? Thanks very much for time. Kenny Tompkins

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I can't confirm this without testing the amp directly, but I would suspect bad capacitors in the pre-amp section. Some of them may have dried out a bit over time. Anyone that is familiar with guitar amps should be able to resolve this for you. The other thing to check is the 12AX7A tubes inside. Swap them around and see if the symptom changes. You may also have a bad tube.

Keep us posted.
Dan

Posted on Jun 27, 2008

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