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Old 05-25-2018, 02:00 PM   #1479
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Default Re: the gutless, bloated, and fried power supply hall of shame

Originally Posted by kevin! View Post
The worst PSU I've had in my hands, a Deer, has burned resistors (with Viva and rulycons capacitors )
Now that's a classic Deer for you!

The burned resistors are a product of a runaway single-transistor oscillator 5VSB design (no optocoupler feedback). One of them is actually used in series with the Vcc power rail for the KA7500 / DBL494 PWM chip. So the voltage there must have been in excess of 30V for that resistor to burn.

And yes, you get Viva and Rulycon caps, haha! And a lovely DOB rectifier for the 12V rail (Diodes-On-a-Bracket)

All things considered, though... I would probably trust that Deer PSU slightly more than the L-Link above. At least the Deer has a 33 mm core transformer, somewhat better heatsinks, and "a lot more" output filtering (relatively speaking, of course ) - not that this means anything with Rulycon caps doing the filtering.

And last but not least.... that CBE fan. These fans are extremely crap quality, but they have surprisingly good sleeve bearings. Once cleaned and oiled properly, they will last a long time. I used one of these as a case fan and later on as a PSU fan for a HiPro PSU that didn't have a shell/case. I haven't oiled that fan in more than 5 years, and it's still running fine (though lately it hasn't seen much use).

Originally Posted by PeteS in CA View Post
OMG! Is that beefless POS good for 200W continuous?
I doubt it. Probably even 150 Watts would be a stretch with that 28 mm transformer, given that this is an old, slow-switching h-bridge design. And that's probably if you load all the rails somewhat equally. The 12V rail appears to have a 12 Amp rectifier, so that limits it to 144 Watts. I seriously doubt you'd be able to pull that much off of it before the output toroid releases the magic smoke. But with the crappy heatsinks of this unit, maybe the 12V rectifier will overheat and short-out to save the output toroid.

And then just imagine the ripple on the 12V rail at that power level. Your mobo will be surfing for sure - no, not surfing the internet, but those huge voltage ripple/noise waveforms from the PSU.

Last edited by momaka; 05-25-2018 at 02:04 PM..
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