I connected a TEC1-12705 to +12V and -12V of a PC PSU (+12v rated 45A, -12v rated 0.5A) then the PSU died. I inspected the PCB and found no burnt traces. What could be damaged?

The IC of the PSU is a JZ6120BD and the -12V rail goes to it. Maybe replacing the IC can bring the psu to working state again? (No caps or resistors were found blown out)enter image description here


closed as off-topic by Eugene Sh., Hearth, Elliot Alderson, Harry Svensson, Edgar Brown Feb 12 at 18:54

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  • 1
    \$\begingroup\$ Sounds like you probably pulled too much current out of the output. I'm not sure what a TEC1-12705 is, googling the part gives currents around 5A, which your negative rail is absolutely not able to handle. \$\endgroup\$ – Hearth Feb 11 at 18:54
  • \$\begingroup\$ It's unlikely that IC is generating the -12V. The reason the -12V goes to that IC is likely to be just for monitoring. Replacing it is unlikely to fix anything. \$\endgroup\$ – Unimportant Feb 11 at 19:31

The −12V rail on PC power supplies is not designed to sink large currents. It's usually limited to well under 1 A, often even 200 mA or less. Injecting a current of 5A or more from the +12V rail is likely to have damaged the −12V regulator.

As this appears to be a cheaply built PC power supply, the most expedient solution will be to replace the unit. Testing and replacing individual components will not be cost-effective, and may cause further damage.

Additionally, the TEC you are using is rated for a maximum voltage of 16.2 V. Exposing it to 24V may have caused irreparable damage to the TEC as well.

  • \$\begingroup\$ The peltier module survived. The run time was less than 10 seconds. It had the plugs connected in 24V configuration because I was regulating the output of a buck converter which would have an input of 24V. But when I connected the peltier I forgot to undo the 24V configuration and the damage was done for. It´s sad to let go the ATX power supply because it had a nice 12V output and cost me around 30 dollars (I live in Uruguay so that pays a month of DSL access) I will check for the regulators and the transformer coils to see if I can find a short. Thanks for the contributions \$\endgroup\$ – Fabio Cesperes Feb 11 at 20:46
  • \$\begingroup\$ Upon further inspection the PSU does not give +V signal through the power good cable (grey) but, it does give 5VSB voltaje. The -12V goes to a coupled inductor through a rectifier. Everything is fine. But I supect a MOSPEC could have been blown. \$\endgroup\$ – Fabio Cesperes Feb 14 at 2:31

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