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IaninOz Guest
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Posted: Sat Mar 22, 2008 12:16 am Post subject: Marantz PCB's |
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I have only just this Easter weekend dragged out my old PM451 (amp) and fixed a problem that forced me to pack it away for a few years. I didn't want to get rid of it as it is part of my Marantz collection.
The problem was the speaker protection delay relay wouldn't operate after the 4 seconds and connect the load. The cause was poor soldering on the PCB. After some really close looking one of the straps that 'jumped' printed circuit tracks was under tension and poor soldering over time allowed it to fracture (probably vibration). It took a lot to find the fault as occasionally it would work, usually when first powered up, then subsequently not - caused me to think the timing capacitor was the fault.
This is the second time I have found dodgy soldering on the board in the AMP, and my tuner (ST551) also exhibits a display drop out which could be removed with percussion (that's giving it a technical tap). This too was poor soldering resulting in dry joints.
My suggestion is check VERY carefully for dry joints. Even to the point of sweating them again. |
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User Guest
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Posted: Sun Jan 11, 2015 6:10 pm Post subject: Sub |
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please picture on the tuner pcb |
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