Re: Computer Power Supply
I finally found my problem. The main filter cap 470Uf 400 volt read .66Uf on my fluke 76 DVM. Therefore I was getting unfiltered AC volts going to IC501 which was blowing the Sh.....t out of it. I replaced this cap with a 470Uf 450V and now the PSU is working just like new.
Thank you guys for all your valuable input.
Old proverb say....if at first you don't succeed, try, try, try again ( William Edward Hickson, 1840)
gdurante
Member
Last Activity: 01-17-2016, 11:33 AM
Joined: 12-26-2015
Location: quebec
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Re: Computer Power Supply
update correction.
My DVM battery voltage was low therefore I could not forward bias the input photodiode. After replacing the DVM battery they all tested OK. I had my daughts?? at the same time I was optomistic. Back to the drawing board.Leave a comment:
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Re: Computer Power Supply
Another update on my dead PSU
After further troubleshooting I discovered that all of the optocouplers (817BX) on the main board are defective. The input photodiode is open. There are 3 of them two for the main supply and one for the SB supply? How could this have happened? Overvoltage spike after a power failure maybe?Leave a comment:
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Re: Computer Power Supply
Thank you for your quick response STJ. One thing I don't understand is why does IC501 blow when I turn on the main PSU if it is only used for the standby 5VDC?
I verified all the output diodes and caps..all OK no short. The main transformer is hard to check with a ohm meter. The only other thing I can possibly conclude is that the main PSU does not switch..possibly the main switching controller like you pointed out?
I will be looking closely at the input section.Leave a comment:
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Re: Computer Power Supply
I replaced IC501 but as soon as I power up the PSU IC501 blows again. I started to troubleshoot further and found shorted D504 Schottky rectifier. I replaced the rectifier and IC501. Powered up the PSU (turned on the main switch in the back) everything is fine, as soon as I soft start the supply (power on computer) IC501 blows again but D504 is OK. At this point I am looking at T501.
I am stumped. Any suggestions?
Thank youLeave a comment:
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Re: Computer Power Supply
R506 is OK it measures 2.2 ohms.
Diode D501 and ZD501 are also OK.
Any other ideas are welcome.
Question: is IC501 output power dependant? Example: for a 600W PSU IC501 is a TNY278PN. For a 700W PSU (Mine), is IC501 also TNY278PN?
Thanks
GDLeave a comment:
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Re: Computer Power Supply
Thank you MAN DOWN UNDER for the superb repair info.
I know that with this info I can now repair my PSU.
Thank you. Any further suggestions would be deeply appreciated.
I have included some PICS of my PSU
THE CANADIAN
GD...Leave a comment:
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Re: Computer Power Supply
I shall do that ASAP.
Thank you for your help.
GDLeave a comment:
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Computer Power Supply
Hello
I have a computer power supply which is dead.
The power supply is manufactured by OCZ model OCZ700MXSP.
After some troubleshooting I found a burned IC501. I cannot identify this IC because it is completely burned.
I was wondering if anybody can help me identify this IC, make any suggestions, and the possibility of getting my hands on a schematic of this supply.
Thank you
GD
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Re: New Members - please post your introductions here
Hello I am a retired Electronic Engineer who likes to design electronic circuits as well as repair every type of electronic equipment.
I am glad to have found this forum so that I can share my knowledge with the world.Leave a comment:
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Re: New Members - please post your introductions here
I am an a retired electronic engineer and in my spare time i enjoy designing circuits for different applications as well as repairing all types of electronic equipment.
I also like to share my designs and ideas on this forum.
Thanks...Leave a comment:
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