Power supply going out
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Author:  Ducksy [ Fri Jul 10, 2015 6:47 pm ]
Post subject:  Power supply going out

Good Day I have done the first stage of tuning of my Theramax 9505, all appears to be a go correct sounds and LED when tuning, problem is I have shorted out two power supplies, also the power feed wires to the board are getting hot ?
There is no damage to the to the board, no smells.
The first power supply unit I purchased with the kit,the scond I had a spare on hand.
I am at a loss, any suggestions please, David. :x

Author:  PAiA-Scott [ Sat Jul 11, 2015 7:21 am ]
Post subject:  Re: Power supply going out

Hello David.

If a power connector has been added and it is on the same metal as the phone connectors, it could be the trouble. It could be putting the plus pole of the supply in contact with the metal of the connector and metal of the phone jack sleeves which wire to the power supply minus pole via the metal panel.

Otherwise, maybe there is a wire extending too much from a solder joint on the board and it is touching the metal case-bottom. This could be the wire from the power switch to the board wiring point "+", or resistor R1 which links it to C1 and D1.

Or, if the antennae mounting hardware is on conductive material, it could be putting the energy from the connected oscillator signals in near contact with the metal-case bottom which is common to the power supply minus pole.

Check too for a stray wire strand or solder blob on the power switch which both works to connect the plus pole of the supply with the board and uses a spare terminal as a ground for the LED with a wire to the power supply minus solder terminal.

Author:  Ducksy [ Sun Jul 12, 2015 1:15 pm ]
Post subject:  Re: Power supply going out

Hi Scott thanks for your help, now in the process of going though all the components and solder joints.
Thanks again David.

Author:  Ducksy [ Tue Jul 14, 2015 12:52 pm ]
Post subject:  Re: Power supply going out

Ok seems we have a winner, no more eating power supplies, not sure what I did, but working now.

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