I an working on a RCA L37WD12. I have a SMPS 1W power supply thats putting out 3.6V DC Standby. The spec calls for 5V DC What the normal variation you can expect on standby voltage?
Thanks
Thanks
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Re: Acceptable Voltage Variance
I don't know if there is an official number, but for ATX power supplies, I believe it is +/- 5%.Originally posted by dhack61 View Post
In any case, 3.6V is way too low for standby.
Check the startup cap next to the SMPS for its capacitance and ESR values.--- begin sig file ---
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Re: Acceptable Voltage Variance
More suggestions.
1) Check the VCC of the SMPS IC to see if it matches the startup voltage compared to its datasheet.
2) Check the DC voltage on the 5V output diode to see if it is 5V.
3) If 1 and 2 are okay, then check the capacitor's capacitance and ESR (secondary section).Last edited by retiredcaps; 04-27-2012, 10:02 PM.--- begin sig file ---
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We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.
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Re: Acceptable Voltage Variance
Thanks for the info. I found a Ceramic Cap soldered on the back of the board that was reading infinite both ways. Its a 220pF 250v Guiess they used it to regulate the voltage down. Gonna replace it and see if that gives me my 5v without it getting 12.8v standby. thanks againOriginally posted by retiredcaps View PostComment
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Re: Acceptable Voltage Variance
If you test a capacitor with a regular multimeter on the resistance setting, then you will either see infinited resistance, or a very quickly asscending number that reaches infinite.
The safety ceramic caps have very tiny capacitances (pico farads vs micro farads for the large aluminum caps), thus they can be charged by the voltage of your multimeter in micro seconds, once they are charged they show infinite resistance, so essentially it charges / becomes infinite resistance faster then the multimeter can detect.Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.Comment
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