Fixing a PSU That Won't Shut Off

JigPu · 04-23-09, 04:57 PM

I've recently acquired a Thermaltake TR2-500 from a friend for free. I don't have a spare machine to test it in at the moment, but its supposed to work great... Except that it doesn't turn off

When plugged in, the PSU will instantly turn on as soon as the switch on its back is switched on. The only way to turn it off is via the same switch. I originally suspected a short between PWR_ON and ground but my multimeter says that there is > 2 MΩ resistance.

With nothing plugged into it, voltages on the rails are pretty much spot-on. Turned off, the PSU has rail-to-ground resistances between 50 Ω and 1 kΩ, and rail-to-same-rail resistances of < 0.5 Ω. Note that I only checked rail-to-same-rail resistances for the motherboard plug (there are just too dang many +12V and +5V lines to check unless its a likely problem

)...

Other voltages I measured:

PWR_OK: +0.09 V (I have no clue what this should be at)
+5VSB: +4.27 V (exceeds the 5% tolerance set by ATX spec)
PS_ON: +2.34 V ("Power should be delivered to the rails only if the PS_ON# signal is held at ground potential." ...And yet its on anyway? WTF.)
-12V: -11.2 V (just within the 10% tolerance set by ATX spec)

Any ideas? I haven't played around much with power supplies, so I haven't a clue what could be wrong...

JigPu

04-23-09, 04:57 PM	Thread Starter #1
JigPu Inactive Pokémon Moderator Join Date: Jun 2001 Location: Vancouver, WA	Fixing a PSU That Won't Shut Off I've recently acquired a Thermaltake TR2-500 from a friend for free. I don't have a spare machine to test it in at the moment, but its supposed to work great... Except that it doesn't turn off When plugged in, the PSU will instantly turn on as soon as the switch on its back is switched on. The only way to turn it off is via the same switch. I originally suspected a short between PWR_ON and ground but my multimeter says that there is > 2 MΩ resistance. With nothing plugged into it, voltages on the rails are pretty much spot-on. Turned off, the PSU has rail-to-ground resistances between 50 Ω and 1 kΩ, and rail-to-same-rail resistances of < 0.5 Ω. Note that I only checked rail-to-same-rail resistances for the motherboard plug (there are just too dang many +12V and +5V lines to check unless its a likely problem )... Other voltages I measured: PWR_OK: +0.09 V (I have no clue what this should be at) +5VSB: +4.27 V (exceeds the 5% tolerance set by ATX spec) PS_ON: +2.34 V ("Power should be delivered to the rails only if the PS_ON# signal is held at ground potential." ...And yet its on anyway? WTF.) -12V: -11.2 V (just within the 10% tolerance set by ATX spec) Any ideas? I haven't played around much with power supplies, so I haven't a clue what could be wrong... JigPu __________________ .... ASRock Z68 Extreme3 Gen3 .... Intel Core i5 2500 ........................ 4 thread ...... 3300 MHz ......... -0.125 V 2x ASUS GTX 560 Ti ............................... 1 GiB ....... 830 MHz ...... 2004 MHz .... G.SKILL Sniper Low Voltage ............. 8 GiB ..... 1600 MHz ............ 1.25 V .... OCZ Vertex 3 ................................. 120 GB ............. nilfs2 ..... Arch Linux .... Kingwin LZP-550 .............................. 550 W ........ 94% Eff. ....... 80+ Plat .... Nocuta NH-D14 ................................ 20 dB ..... 0.35 C°/W ................ 7 V "In order to combat power supply concerns, Nvidia has declared that G80 will be the first graphics card in the world to run entirely off of the souls of dead babies. This will make running the G80 much cheaper for the average end user." "GeForce 8 Series." Wikipedia, The Free Encyclopedia. 7 Aug 2006, 20:59 UTC. Wikimedia Foundation, Inc. 8 Aug 2006.
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Fixing a PSU That Won't Shut Off

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