<div dir="ltr">Do the resistors have their power rating on them? 1.6A at 12V is 19.2 watts total. You'll need some hefty resistors to sink that much power into. <div><br></div><div>Out of curiosity, how much power do you actually need from the 5V rail? Single voltage switch mode power supplies can be had for under $50 with decent amperage ratings. </div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><div>--</div>Wyatt Zacharias<div><br></div></div></div></div>
<br><div class="gmail_quote">On Wed, Feb 17, 2016 at 11:54 AM, Trevor Cordes <span dir="ltr"><<a href="mailto:trevor@tecnopolis.ca" target="_blank">trevor@tecnopolis.ca</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">On 2016-02-15 Hartmut W Sager wrote:<br>
> The -5V and -12V are probably fine with no load, but the +12V line<br>
> should have at least the minimum required load (whatever that might<br>
> be). Just use a suitable power resistor (power resistor means it<br>
> won't fry into a molten lump) on the +12V line. In the absence of<br>
> info on the PS label, I'd go for loading the +12V line with about 10%<br>
> of its maximum power/amps. Use V = IR and P = IV to do the algebra<br>
> to get the right resistance (ohms).<br>
<br>
</span>Thanks for the tip! The old PS indeed says a minimum on the +12V of<br>
1.3A. I paralleled 2 15ohm power resistors (5%; the big huge white<br>
rectangle ones) to approximate a 1.3A or higher (1.6 actually) load. I<br>
only had a limited selection of power resistors around here.<br>
<br>
I can get the whole unit to power on now, and seems to try to boot and<br>
blink some LEDs, yay!<br>
<br>
BUT the power resistors get REAL hot REAL fast. Like too hot to touch<br>
in under 30s. Does that sound right? Not sure I can deliver that to<br>
customer like that. Any other ideas? Different resistors? Maybe try<br>
a "real" load, but what?<br>
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