V3 Universal Power Supply Circuit Board

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#601
UncleMud said:
Earlier in this thread I successfully tested my V3 board with a 12v transformer using 10k 1 watt resistors as a load. I would like to test the unit now that I have connected the recommended toroid to the PSU. The transformer is a 625VA model with dual 45v secondaries.
Will the same resistors be appropriate for testing, or will I need a more rugged option?
Click to expand...

Review , with 45 Vac secondaries , voltage rails should be + 62 Vdc and - 62 Vdc

You've set R9 and R10 = 22 K , 3 Watts

The LED resistors R20 and R21 = 10 K , 1 Watt

P = V^2 / R = ( 62 Vdc ) ^ 2 / 10 K = 0.38 Watts

So Load resistors of 10 K , 1 watt are fine .

... recall , it takes 5 x Tau to discharge those massive caps ( see post #578 )

So keep these load resistors in because the caps will discharge faster

This is now a lethal voltage , so wear rubber gloves when taking a measurement .

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#603
Hi,
Im starting to build an Aleph Jzm with the universal power supply pcb. Ive had thsese Ohmite heatsinks in my parts bin for years As you can tell by the picture, their is a paper thin gap between the heatsinks. Probaby a no-go???? what say you experts
Can anyone recommend a proper sized heat sink as the BOM reccomended ones are out of stock
Thanks


PCB_Heat Sinks.jpg
 
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