Truepower 2.0 recap and repair

[PCBONEZ]

Re: Truepower 2.0 recap and repair

What did you end up using in place of the 4700uF and 3300uF caps?

[Krankshaft]

Re: Truepower 2.0 recap and repair

I personally was able to use the original 4700 caps they were 12.5 Pana FC series.

It took some coaxing but they were within 3mms of the board and the PSU is fine.

[Krankshaft]

Re: Truepower 2.0 recap and repair

Ok if you want this PSU working here is a blow by blow on what to check.

I recently repaired my D-Link Wireless B routers switching PSU using this method. It turned out in that case the PWM IC was dead.

Lets assume for a minute that the transformers are fine since most likely they are.

Check the input capacitors and rectifier.

Is voltage present at the primary switching MOSFET?

Check the Mosfet with the diode checker.

Check all of the secondary diodes with the diode checker (they will be on the heatsink near the secondary caps) are they fine?

Do you have 5 volts on the standby wire?

If not check the standby supplies PWM IC, Mosfet, and Rectifier.

Check for pulses out of the standby PWM to the gate of the standby FET.

This supply may combine the PWM and FET into one package or they may combine the main and standby supplies into one PWM IC.

To find out which look up the ICs at alldatasheet to see what they do.

Do you have voltage on the green (PS ON) wire?

If not check the PWM IC.

[Kaine]

Re: Truepower 2.0 recap and repair

Lets assume for a minute that the transformers are fine since most likely they are.

agreed

Check the input capacitors and rectifier.

all caps have been replaced with new ones except primary caps, which i have little reason to suspect beyond being FUs. I could replace them but would rather not unless absolutely necessary.

Is voltage present at the primary switching MOSFET?

I'm trying to avoid live testing at the moment. I'm game only if you can tell me exactly what setting my multi should be on and where i should stick my probes. I'm pretty cautious about live testing for various reasons.

Check the Mosfet with the diode checker.

Which mosfet? so far every one i've looked at checks out ok

Check all of the secondary diodes with the diode checker (they will be on the heatsink near the secondary caps) are they fine?

Remember that one of the original, immediately obvious problems with this psu was a diode that had failed (in fine style, too) all others in the area check out. I only have limited access to components and i am sick to death of taking components in and out.

Do you have 5 volts on the standby wire?

no.

If not check the standby supplies PWM IC, Mosfet, and Rectifier.

Check for pulses out of the standby PWM to the gate of the standby FET.

This supply may combine the PWM and FET into one package or they may combine the main and standby supplies into one PWM IC.

correct me if i'm wrong but won't this require a CRO? because i don't have one. Working with basic kit here, Multimeter functions only please.

To find out which look up the ICs at alldatasheet to see what they do.

I've got a fine collection of data sheets going but i certainly don't have all of the components... some of them i can't get close enough to see part numbers because of how crowded the board is.

Do you have voltage on the green (PS ON) wire?

I have no activity at the motherboard plug at all.

If not check the PWM IC.

Assuming i can find it, how do i check it?