I have changed the damaged capacitor and resistor and still i have DC and AC power on the bridge ,in addition i have around 155 DC v power on the cap,but still no light on the display of the printer whose model is hp Learjet 5200?
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6\$\begingroup\$ HP do Learjets too now? \$\endgroup\$– Anthony MayCommented Jun 5, 2015 at 14:09
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\$\begingroup\$ Huh? What? - - - \$\endgroup\$– Olin LathropCommented Jun 5, 2015 at 14:10
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\$\begingroup\$ To answer your title: because 220volt not 110v. To answer your question: ??? \$\endgroup\$– AsmyldofCommented Jun 5, 2015 at 14:13
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1\$\begingroup\$ No, the problem is that you are not saying anything relevant to help you. We haven't a smidge of a clue of what you are even talking about. \$\endgroup\$– AsmyldofCommented Jun 5, 2015 at 14:14
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3\$\begingroup\$ Lets rewind a little. Why does it surprise you that connecting a 110V power supply to 220V causes it to be damaged? Its rated at 110V for a reason. You exceeded its design specification, and it died. \$\endgroup\$– brhansCommented Jun 5, 2015 at 14:42
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If this is like many switching supplies there is a doubler configuration at the input so you'd expect to see about 300VDC across two series capacitors. Regardless, by applying double the input voltage the hapless user will have easily exceeded the limits on several parts.
I would expect the damage to go beyond the capacitor and extend at least to the BJT or MOSFET power semiconductors. Those will have to be replaced. Chances are that if you see a sensible high voltage supply that there is also a blown fuse or traces blown off the board, and when those are repaired they will immediately blow again (perhaps causing more damage at the same time, especially if the repair is 'better'). Power semiconductors tend to either go short or physically pop (explode, chunks of epoxy flung off, etc.).
Since you mention aircraft, in aircraft terms this would be comparable to a 'prop strike'- a severe event that requires major parts to be properly replaced.
answered Jun 5, 2015 at 14:30
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\$\begingroup\$ Tnx I have found that the transformer has been burn. \$\endgroup\$– newdayCommented Jun 7, 2015 at 4:21
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\$\begingroup\$ Sad, but not surprising. Thanks for the feedback and post-mortem. \$\endgroup\$ Commented Jun 7, 2015 at 4:24