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Power supply when i boot my computer the red light blinks once every second what is a power supply crowbar and can be repaired

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A crowbar or crowbar circuit is an electrical circuit used to prevent an overvoltage condition of a power supply unit from damaging the circuits attached to the power supply. It operates by putting a short circuit across the voltage source, much as if one dropped a tool of the same name across the output terminals of the power supply. Crowbar circuits are frequently implemented using a thyristor (also called an SCR) or a trisil or thyratron as the shorting device. Once triggered, they depend on the current-limiting circuitry of the power supply or, if that fails, the blowing of the line fuse or circuit breaker.
A crowbar circuit is distinct from a clamp in that, once triggered, it pulls the voltage below the trigger level, usually close to ground. A clamp prevents the voltage from exceeding a preset level. Thus, a crowbar will not automatically return to normal operation when the overvoltage condition is removed; power must be removed entirely to stop its conduction.
The advantage of a crowbar over a clamp is that the low holding voltage of the crowbar lets it carry higher fault current without dissipating much power (which could otherwise cause overheating). Also, a crowbar is more likely than a clamp to deactivate a device (by blowing a fuse or tripping a breaker), bringing attention to the faulty equipment.


The power supply is bad. I would not try to fix it.

Posted on Mar 01, 2008

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http://h20565.www2.hp.com/portal/site/hpsc/template.BINARYPORTLET/public/kb/docDisplay/resource.process/?spf_p.tpst=kbDocDisplay_ws_BI&spf_p.rid_kbDocDisplay=docDisplayResURL&javax.portlet.begCacheTok=com.vignette.cachetoken&spf_p.rst_kbDocDisplay=wsrp-resourceState%3DdocId%253Demr_na-c00448584-2%257CdocLocale%253Den_US&javax.portlet.endCacheTok=com.vignette.cachetoken
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Power Green On (S0) Computer on
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Power Green 1 blink every 2 seconds (S3) Suspend to RAM
Power Green Off (S4) Suspend to Disk (if applicable)
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Power Red* 6 blinks 1 second apart No graphics
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Power Red* 8 blinks 1 second apart Invalid ROM
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Hi Kindly let me know how many times the red light blinks
Condition Code Service Actions Processor thermal protection activated. Power LED blinks red twice, once a second, followed by a two second pause.
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  2. Open the hood, press the power button, and see if the processor fan spins. If the fan is not spinning, make sure the fan cable is plugged into the cable header on the system board, and that the fan is properly installed and seated.
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