Thermaltake TR2 750w Need help with resistor value

[NickLoC]

I need to find out what value this resistor is. Having a hard time finding out. Replaced a bad main cap, a power mosfet and a smd resistor. This resistor measures .02ohm.

[stj]

Re: Thermaltake TR2 750w Need help with resistor value

it's fine i suspect.
the first 2 bands are black,red
that's 0,2

[NickLoC]

Re: Thermaltake TR2 750w Need help with resistor value

Why all the other bands then?

[stj]

Re: Thermaltake TR2 750w Need help with resistor value

tolerance, temperature coeficient etc.

[R_J]

Re: Thermaltake TR2 750w Need help with resistor value

Black = 0
Red = 2
Green = 5
Gold X 0.1
Green = .5%
I don't know why they used black as the first band because all calculators just ignore the zero.
That calculates out to 2.5 ohms which is likely wrong, what you measured is likely correct, .025 ohms

[momaka]

Re: Thermaltake TR2 750w Need help with resistor value

If it reads that low on resistance, it is more than likely fine. Resistors go open-circuit or high resistance when they go bad.

[NickLoC]

Re: Thermaltake TR2 750w Need help with resistor value

Thanks for the help. Does anyone know where you can get schematics for computer power supplies?

[momaka]

Re: Thermaltake TR2 750w Need help with resistor value

You may or may not be able to find one for your PSU. Best way to troubleshoot is to note down what the symptoms of the PSU are, then start from there.

If the PSU appears completely dead (i.e. won't power a PC and won't start when you short the PS_ON wire to ground), start with the 5VSB rail. When plugged in, there should be about 5V on the 5VSB wire relative to ground. If you don't have 5V there, nothing else in the PSU will work, so that's where you start troubleshooting by testing components in the 5VSB circuit.

If the 5VSB is present but the PSU refuses to start, it can be a number of things. So here, the troubleshooting will depend on the symptoms your PSU has - i.e. if the fans twitch, that means there is either a short-circuit somewhere, or one or more of the rails is not regulating properly. If no symptoms (completely dead PSU, but 5VSB present), then check the primary-side switch devices, primary-side controller voltage, and secondary-side PS_ON signal generation circuit. Also APFC components, if the PSU has APFC.

[stj]

Re: Thermaltake TR2 750w Need help with resistor value

there is a russian site with lots of psu schems

try searching with yandex