Question about Belkin (F6C1500-TW-RK) (F6C1500TWRK) UPS System

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Belkin F6C1500-TW-RK 1) Batteries needed changing. 2) Installed new batteries. (After checking with a load meter, both were fully charged & OK.) 3) Without plugging anything into the the UPS or turning it on, I plugged it into a wall outlet. 3) There was an instant small explosion inside the unit. 4) Pulled off the cover and found 8 MOSFETs that were destroyed. Their part number is: FQP16N25C by Fairchild Semiconductor. 5) The marking on the PCB indicate they are in positions marked # Q501B through Q508B. We have 10 of these units here at our main office and another one of them did the same thing a few months ago. My question, do you think just replacing the MOSFETs will cure the problem or is it likely there is another component causing this problem. A side note. We have, during the past few months, changed the batteries in all of the units and have had problems with only two of them.

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That small explosion could have been caused by only one thing - an electrolytic capacitor that has failed. When it has failed it turned into a big short that has massively overstressed the power transistors so they all failed. The live of a filtering capacitor isn't greater than 5 years so all your other UPS units are close to meeting the same fate. Check all capacitors and all other components that might have been damaged by the short and look at the capacitors from the other units - bulging is a sign of imminent failure.

Posted on Jul 06, 2010

  • BV Alvarez Jul 06, 2010

    OK, I just made a very careful examination of all the capacitors and none show any signs of bulging. I will next remove each one and check them for shorts. I will let you know if I am successful in finding a bad capacitor.



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I returned from a trip to find my F6C1000W-TWRK and all devices powered off with no lights. Tried to reset the AC breaker on the back but it wasn't tripped. I confirmed good mains power then tried to power it on by holding the main power button but no action. removed the batteries (2x 7AHr 12V sealed Pb-acid) and confirmed one was 0V and the other around 2V. I attempted to charge each indpednatly on a Jusni iCharger but both wouldn't take a charge.

As this seemed suspicious that both batteries would fail simultaneously, I took the unit apart and found the two 40A on-board fuses for the DC lead intact. Then on inspecting more, there was a distinct brown discoloration around the large aluminum heatsink with "IG0" component mounted under it (and presumably "IG1" but I didn't dismantle further).

Bottomline is it appears this component can eventually overheat (likely due to an electrolytic going bad and stressing it beyond it's thermal limits until it finally fails).

I haven't attempted repair as new quality batteries are approx $60 shipped so I am going to buy an all new unit.

If anyone attempts repair for this failure mode, please post back your experience.

Thanks !

Mar 02, 2013 | Belkin (F6C1500-TW-RK) (F6C1500TWRK) UPS...

1 Answer

I have a Belkin F6C1500-TW-RK UPS that requires two batteries - the D5779 model. My question is how do I replace the batteries in the unit. I no longer have the user manual.

You can download a user manual from the Belkin WEB site.

May 29, 2011 | Computers & Internet

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My mercury radiant 1000 inverter dose not give backup time. although my battery is new.and also tell me the salutation of increase the charging.give answer urgent pleas.

Dear, Please check following

1. Are you using correct gauge of wire for batteries (Specification mentioned in the manual)
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Oct 11, 2010 | Belkin (F6C1500-TW-RK) (F6C1500TWRK) UPS...

1 Answer

Not holding a charge can it be repaired or better to replace?

If your UPS is not holding Charges, this means that the Battery does not carry the load when AC fails. Check to see that the batteries are okay by testing the individual batteries on load using a potentiometer load with multimeter. If the battery voltage drops below 10V replace the batteries and your UPS be okay

Jun 08, 2010 | Belkin (F6C1500-TW-RK) (F6C1500TWRK) UPS...

1 Answer

Belkin F6C1500-TW-RK discharged new batteries, won't recharge

This sounds like a battery issue...I would have the unit and batteries tested at your nearest batteriesplus store...

May 07, 2010 | Belkin (F6C1500-TW-RK) (F6C1500TWRK) UPS...

1 Answer

Belkin F6C1500 UPS will not run on batteries

I think your issue is that the unit is overloaded. Try this...unplug a couple of items to get the load lower...then pull the plug from the wall...did it keep those few units running while disconnected...if not then the unit could still be overloaded...unplug everything but a small electric the same thing to see if it will keep the radio playing. If this doesnt work, go by your nearest batteriesplus store and they can help.

May 04, 2010 | Belkin (F6C1500-TW-RK) (F6C1500TWRK) UPS...

1 Answer

Battery connection.

Here's the manual with battery replacement instructions. If not detailed enough, give their support line a call.

Toll Free from USA: 1 800 2BELKIN

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Belkin ups not working properly.... green and RED light on ...indicates bad battery. But unit not more than 1 yr old, no battery time at all when plug pulled...not enen i min on (desk to an d monitor

Your batteries are weak...(causes
1:-not powering the UPS for a longtime
2:- long use(3 to 4 years) ) will have to replace them
PLEASE RATE ME.................

May 25, 2008 | Belkin (F6C1500-TW-RK) (F6C1500TWRK) UPS...

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