Roland TD-7

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EmptySet
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Roland TD-7

Post by EmptySet » Tue Jun 07, 2011 12:34 pm

I have a Roland TD-7 with a strange behavior. When it is powered up, the output is very quiet… almost nil. After about 2-3 min of "warming up", suddenly the volume begins to increase with some mild distortion, eventually reaching full volume and no more distortion. Then, the unit seems to operate normally. Has anyone ever seen this? Or can anyone recommend some things to look for? I'm comfortable with electronics repair, soldering, etc… The power supply is a wall wart with 120VAC going in and 12VAC coming out (yes, AC). It's basically a transformer. (power supply was going to be one of my first suspicions, but just on a hunch) Any ideas where else I might look?

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snod_donkey
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Re: Roland TD-7

Post by snod_donkey » Tue Jun 07, 2011 1:44 pm

Maybe check DC volts when its cold... if its an AC power unit it will have some sort of rectifier and regulators inside the module

If those voltages are ok then maybe an op-amp ??

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EmptySet
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Re: Roland TD-7

Post by EmptySet » Wed Jun 08, 2011 3:04 pm

snod_donkey wrote:Maybe check DC volts when its cold... if its an AC power unit it will have some sort of rectifier and regulators inside the module
If those voltages are ok then maybe an op-amp ??
Both good ideas. i'll have to check them both out. thanks!

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samuraipizzacat29
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Re: Roland TD-7

Post by samuraipizzacat29 » Wed Jun 08, 2011 9:27 pm

Obviously power is the first place to go, but beyond that, I'd check all the caps around the amp ic. sounds like a dumb question - but does it smell funny? burnt caps generally smell kinda bad. There's a thread around here somewhere for technicians....

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EmptySet
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Re: Roland TD-7

Post by EmptySet » Sat Jun 11, 2011 4:52 am

samuraipizzacat29 wrote:Obviously power is the first place to go, but beyond that, I'd check all the caps around the amp ic. sounds like a dumb question - but does it smell funny? burnt caps generally smell kinda bad. There's a thread around here somewhere for technicians....
I poked around and nothing smells burnt nor looks burnt. The thing works fine once it gets past its "warm up" period.

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