Do ADSL filters "go bad"?

NathanE · 12 Jun 2009 at 16:18

My ISP reckons the reason my line has suddenly gone from 14Mbit to just 1.4Mbit and with frequent desyncs is because my filter has "gone bad".

Is this plausible? :confused:

It is a standard BT "Engineer Install" (circa 2001) wall socket that has a built-in filter.

osc89er · 12 Jun 2009 at 16:27

We used to replace a lot of old microfilters when I was working for an ISP. Seemed to fix the issue the majority of the time.

Of course you have to keep in mind that this was a low paid, poorly trained team.

Scooby_WR1 · 12 Jun 2009 at 16:28

Hi,

I had a netgear one go on me not long ago so yes they can go bad.

NathanE · 12 Jun 2009 at 16:29

OK, learn something new everyday like they say.

I will try the modem out in the test socket behind the face plate when I get home.

pennywise · 12 Jun 2009 at 17:50

If it is the faceplate, you can pick up new ones for under a tenner in many electrical wholesalers and the like.

swinnie · 12 Jun 2009 at 17:53

If a filter has things such as capacitors in it, it is possible the components have 'migrated' - its a fault seen on motherboards when they burst, effectively their values change, changing the way they behave on the circuit.

I changed a filter at my dads place, and the sync rate doubled!

Burnsy2023 · 12 Jun 2009 at 17:58

swinnie said:
If a filter has things such as capacitors in it, it is possible the components have 'migrated' - its a fault seen on motherboards when they burst, effectively their values change, changing the way they behave on the circuit.

Indeed

oxygene · 12 Jun 2009 at 18:01

Wtf, this exact thing happened to me a couple of weeks back. 14mb, then overnight it wont sync above 1.4mb and keeps dcing! With Be Internet though, but there were some bt engineers up a pole nearby shortly before.

Phemo · 12 Jun 2009 at 18:15

You can rule your filter out quite easily. Just take the filtered faceplate off to expose the test socket and just use a BT to RJ11 cable to plug the test socket directly into your router - no need to even have a filter hooked up just for testing your router's sync.

EsaT · 12 Jun 2009 at 18:16

Overvoltage for example from lightning strike can destroy capacitors but those coils should block high frequencies (like that of lightning) well.
http://www.epanorama.net/documents/telecom/adsl_filter.html

NathanE · 12 Jun 2009 at 18:33

Well I just got home and it's synced up again at more or less 14Mbit again.

Router says there has been 25 resyncs though, just today.

God knows what's going on. This happened last Sunday as well - I thought it was a one off because there was heavy rain or something.

Maybe the Tesco's they are building nearby is affecting it somehow?

Next time it happens though I will definately try out the test socket to rule out my filter.