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 Power supply going out 
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Joined: Fri May 29, 2015 9:27 pm
Posts: 3
Post 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


Fri Jul 10, 2015 6:47 pm
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Joined: Sun Nov 09, 2008 2:49 pm
Posts: 726
Post 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.

_________________
Scott Lee
scott@paia.com


Sat Jul 11, 2015 7:21 am
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Joined: Fri May 29, 2015 9:27 pm
Posts: 3
Post 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.


Sun Jul 12, 2015 1:15 pm
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Joined: Fri May 29, 2015 9:27 pm
Posts: 3
Post Re: Power supply going out
Ok seems we have a winner, no more eating power supplies, not sure what I did, but working now.


Tue Jul 14, 2015 12:52 pm
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