Power cut and subsequent problem

[EddieM]

Today at around 10:00am we had a brief powercut, this is not at all uncommon round here, so didn't think anything of it. Power was off for around 2 perhaps 3 minutes, and most of the house rebooted ok. The broadband router was dead as a dodo though.

So I checked the fuse in the power flylead, that was OK
I checked the flylead was outputting 230v AC (having remembered to carefully check what range the MM was set to ) OK
I then removed the phono power plug to the router from the transformer, no voltage.
I disconnected the transformer from the mains, and let it rest a while (aren't I kind)
After about 20 mins or so, I reconnected the transformer to the mains flylead, checked the output voltage on the transformer 6.15v which is correct.
Plugged the transformer lead back into the router, nothing still dead.
Checked the voltage from the transformer again 0v dead.
Tried this a few times, each time I plugged the transformer into the router it would go from 6.15v output to 0v.

So question is what would cause that? apart from the blindly obvious that the transformers shot.

And yes you guessed it I opened up the transformer in my usual optimistic way, hoping for a neon sign pointing to the culprit. No such luck as usual.

I've remedied the situation, with a new transformer, but was curious to know which bit of the transformer had most likely given up the ghost?

I've put this in electrics as I think it will get a more relevant audience that hardware. TIA.

 

[wingcoax]

Does the tranny smell? probably the secondary windings blown with a power surge. You could always buy a surge protector if the power goes as often as you say.

 

[EddieM]

Does the tranny smell? probably the secondary windings blown with a power surge. You could always buy a surge protector if the power goes as often as you say.

Oh err missus, I'm not generally known for sniffing trannies, but no it didn't!

Good plan re surge protector, thanks for the reply. I'd love to have the knowledge to be able to diagnose these things, as I have a hatred of having to chuck stuff away when probably only one wafer thin component has gone wrong. (I think it's called being a tight fisted get!)

 

[wingcoax]

No room in my garage cos of "I may find a use for that"

 

[ColJack]

4 days and a dozen trips to the tip, plus 3 visits from the tat man and a van from the cancer charity shop, just because my nan and grandad were one of those...
decades worth of housekeeping diaries ( june 7 1984: paid gas bill, etc.. )..
years worth of the local parish magazine..
half empty tins of paint that were never used again, a chest of drawers in the garage full of brand new bits of old morris cars from when he worked at morris.. as well as a drawer full of 78 rpm records..
an old toaster that was replaced with a new one one christmas ( still works, might need it one day if this one breaks... ) and so on..

 

[EddieM]

I'm not that bad!! Yet I personally detest those jam jar full of old rusty nuts bolts and screws. Any screws etc, that are removed from a job are routinely scrapped. I just like things to last.... well that said I suppose the router is about 7 years old, so probably shouldn't grumble!

 

[ColJack]

would it happen to be a Belkin by any chance?

I have a knackered router and you can have the power supply if you want it.. providing that it fits of course..

 

[Lectrician]

Sounds like the router is faulty, and the transformer is shutting down when presented with the fault. It is auto resetting itself.

 

[electronicsuk]

Sounds like the router is faulty, and the transformer is shutting down when presented with the fault. It is auto resetting itself.

It's a possibility, but equally, it may just be unable to cope with any load, but read fine when open circuit. Without a dummy load and testing, it's difficult to say.

 

[EddieM]

'Tis fixed, new transformer, no it's an old BT 1800 HG.

 

[ericmark]

I have noted routers, modems often have transformers AC output 12V at 1A which is unusual as most the other electronic equipment uses inverters with DC output and much smaller of course for same power.

However I have not had a transformer fail as yet they do seems to be more robust than the inverters you get to charge phones etc.

The inverter for my laptop decided it would no longer allow me to charge and use my laptop and started to auto shut down when power requirement raised and I had to get a Universal replacement higher output replacement I will guess some thermal trip has got week.

Out of interest I wonder if inverter or transformer failed as I know we tend to call inverters transformers?

 

[Goldberg]

I have noted routers, modems often have transformers AC output 12V at 1A

Are you saying that the external output of these is AC?

I ask because I have about 20 routers and modems here - an assortment of D-Link, Netgear, Belkin, LinkSys and ZyXel - and not one single one of them takes an AC input.

Do you have an example of a make/model that does?

 

[EddieM]

Sounds like the router is faulty, and the transformer is shutting down when presented with the fault. It is auto resetting itself.

No the router showed no power at any point. Simply after connecting the transformer to the router, the transformers output would drop from 6.15v DC to 0v

New transformer seems to have fixed the problem. However, for futuer reference, I must remember to make a note of the routers settings for the day that inevitably it'll go pop.

Must say the amount of power it uses 2A @ 6v surprises me a bit.

 

[rebuke]

2A at 6V is only 12W or so, which isn't actually that much, considering your average PC uses around 120W...

 

[EddieM]

2A at 6V is only 12W or so, which isn't actually that much, considering your average PC uses around 120W...

A'int doing much powerwise though