Antec Smart Power Panasonic UQ Question

[Krankshaft]

Well I'm on my 4th Antec SP recap I just finished it off but I was short 1 1000uf 10V tall and skinny cap for the standby supply .

Oh well I needed to reorder from Digikey anyways while I was cleaning up the bench with my magnet (alot of lead clippings) I noticed one of the Panasonic UQ series 85 C line filters was slightly bulged.



On all of the other SPs I recapped they were fine and the tops were nice and flat like the one on the right.

In addition to that based on them being manufactured by Panasonic I thought that I didn't need to worry about them.

Am I being over paranoid here or is this cap actually bulging?

I seriously hope that I don't have to worry about the other recapped supplies.

[i4004]

Re: Antec Smart Power Panasonic UQ Question

what's its esr?

these rarely go, but they obviously can go
https://www.badcaps.net/forum/showpo...&postcount=132
but that was cheap design and a lot of missing components...

check these resistors


and replace cap if it has high esr.

[Krankshaft]

Re: Antec Smart Power Panasonic UQ Question

Good idea I forgot I had one .

False alarm it measured 0.5 ohms the same as its neighbor that didn't look bulged.

I noticed those resistors when desoldering the caps for an ESR measurement.

I'd expect the bleeder resistors to at least be through hole no wonder why they can burn out in those fragile little SMT packages not to mention leave a shocking suprise for people when they do.

On a related note the trend I observed is on this supply too.

One of the Fukyuu standby caps had leaked electrolyte (ESR over 99 ohms) and the other that was bulged didn't leak yet (8.5 ohms) the primary side of the standby transformer began overheating and discolored the board from light biege to a darker brown color. Nothing serious but noticeable.

A very good indicator as to if you are catching the failure early or a little late.

[Brian C]

Re: Antec Smart Power Panasonic UQ Question

I suggest you pump in DC voltage of 30V ~ 50V to the rectifier input and measure the voltage drop across each capacitor. The MOVs and Capacitor impedance mismatch due to long time usage may cause imbalance voltage applied across the 2 capacitors. Resistor divider of 330kOhm is too high (IMHB), cannot compensate for the impedance mismatch of MOVs and capacitors. Usually I use 47kOhm ~ 82kOhm.

[Krankshaft]

Re: Antec Smart Power Panasonic UQ Question

I assume that PFC supplies with only one input cap don't suffer from this inbalance?

[japlytic]

Re: Antec Smart Power Panasonic UQ Question

Both 200/250V capacitors should be replaced at the same time as a pair.
Active PFC supplies generally have one 400/450V electrolytic capacitor.