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Re: Start Point - Click in Loop? EDP DC Offset
so the butler was...er...badgered... and managed to dredge up the answer. 

Indeed, this has all the hallmarks of the well known DC offset
problem.

This except from the LD archives explains the fix,
it's from Kim Flint.

andy


anyway, for John, here's how to set the trimpot:

*********************************************

This requires that you actually open up the unit, and have it opened with
the power on. *Please follow appropriate electrical safety rules!!* If you 
are not careful and you fry yourself, please don't blame me!
There's a trimpot on the PCB, near the left side, by the volume knobs. It's 
job is to trim a dc offset from a VCA. Sounds like your's is not set right
for some reason, which would cause the thump you hear.

To set it you need to run one of the built in diagnostic tests. The test
basically turns the VCA on and off at about 60Hz, so if there is an offset
you can hear the resulting tone in an amplifier. (or see it on a scope,
whichever way you like.)  While that's going, you adjust the trimmer until
the tone/waveform reaches it's mimimum.

To get into the trimmer test, Start the unit while holding the Parameter
and Record buttons down. Keep them held while the startup screen goes by,
until the display shows all t's. Then let go. Should say 7F. Press
parameter so the "Keys" LED is lit, then press Insert to start the trimmer
test.

You should hear a ~60Hz tone in an amp. (turning input volume off, mix to
"loop", and the output volume up helps.) The tone will change in level as
you adjust the trimpot. Adjust to where the tone is at it's lowest level.
(you'll still hear hashy noise sounds, but the 60Hz should become nearly
inaudible.) After you set the trimmer, pressing parameter again will stop 
the test. Then you can turn the echoplex off and power back up normally.

**********************************************
kim



openjam@aol.com wrote:
My EDP (Oberhiem with Loop 3, 5.0) has developed a click at the start point of each new loop. Sometimes its more audible then others. 

Any ideas?
An obvious suspect would be the start point led - perhaps something has failed.
I tried the archives but could not retrieve any similar symptoms. Please direct if you know of a case. 

Thanks
Todd Quincy