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Old 8th June 2009, 02:10 PM   #1
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Default Hafler Five Hundred problem

I am having a problem with a Hafler Five Hundered. I am intermitantly losing channnels in and out. When the channel fades, sometimes the left, sometimes the right, I can turn the power switch off and back on quickly and both channels will work fine again for a bit and then one will fade and I can do the same thing over again. Everytime I flip the power switch off and back on, both channels work properly again. If I leave it on one side will be fine and one will fade in and out. What is going on? when both channels are going it sounds good. What should I look at" Any help greatly appreciated. Thanks, Kyle
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Old 8th June 2009, 04:05 PM   #2
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Get the manual on the net. Most probably a defective aging TR401 inrsuh limiter. Seems to often happen.
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Old 8th June 2009, 11:38 PM   #3
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Default Hafler 500

Cool thanks. One thing I did notice is that after letting it sit all night long powered on, it doesn't seem to be having channels drop out. It looks to be a component which functions when warm but not correctly when the unit sits off for awhile. Would this limiter be consistent with that?
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Old 9th June 2009, 02:13 PM   #4
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you can consider replacing it entirely with a soft start circuit that controls a relay with a power resistor for the current limiting on start up. there are circuits you can find if you search here...

Or alternately, bypasses the present part entirely after a start up period of a few seconds... same idea.

http://www.bearlabs.com -- Btw, I don't actually know anything, FYI -- every once in a while I say something that makes sense... ]
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Old 10th June 2009, 12:38 PM   #5
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It can't be the inrush limiter.

I would check the speaker relay. Pop the cover and run a pair of jumpers across the relay contacts.
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