SteveHill
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[Moved] Power Supply MX9000 +17 VDC Question
I have a Behringer MX9000 400 Watt Power Supply which did what most of them do... blow out the LM350 on the +17 VDC side. I replaced all three LM350's with LM388T's, as well as replaced all of the Cap, Diodes, resistors and the LM317 and LM7818 power transistors.
The PS shows correct voltages of -17, +17, +48, +12 & +5 at the PS pin- out but when connected to the mixer, the +17 is absent. I have also checked to be certain there is not a loose and intermittent connection at the pin-out.
I have two MX9000 mixers with one good PS so I am able connect the good PS to either mixer and the +17 is present.
I'm thinking the +17 on the bad PS drops out once a load is put on it but I don't have the knowledge to understand what component might be causing the problem. I have replaced various newly install components (like the Cap's, Diodes and LM388T's) with other new components thinking maybe a new component might have been bad but so far... I have not been able to resolve the problem.
Also, the AC input voltages from the transformer to the PS board are present and correct.
Any suggestions are welcomed.
Thanks for your consideration,
Steve Hill
I have a Behringer MX9000 400 Watt Power Supply which did what most of them do... blow out the LM350 on the +17 VDC side. I replaced all three LM350's with LM388T's, as well as replaced all of the Cap, Diodes, resistors and the LM317 and LM7818 power transistors.
The PS shows correct voltages of -17, +17, +48, +12 & +5 at the PS pin- out but when connected to the mixer, the +17 is absent. I have also checked to be certain there is not a loose and intermittent connection at the pin-out.
I have two MX9000 mixers with one good PS so I am able connect the good PS to either mixer and the +17 is present.
I'm thinking the +17 on the bad PS drops out once a load is put on it but I don't have the knowledge to understand what component might be causing the problem. I have replaced various newly install components (like the Cap's, Diodes and LM388T's) with other new components thinking maybe a new component might have been bad but so far... I have not been able to resolve the problem.
Also, the AC input voltages from the transformer to the PS board are present and correct.
Any suggestions are welcomed.
Thanks for your consideration,
Steve Hill
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