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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

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

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "Questions on the repair of consumer electronics, appliances, or other devices must involve specific troubleshooting steps and demonstrate a good understanding of the underlying design of the device being repaired. See also: Is asking on how to fix a faulty circuit on topic?" – Eugene Sh., Hearth, Elliot Alderson, Harry Svensson, Edgar Brown
If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\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
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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.

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  • \$\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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