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D Link ADSL Signal Drops Too Frequently during POWERCUT -Using Inverter-- Options Needed

post #1 of 7
Thread Starter 
Hello

My case:
Have a DLINK 2640T Wifi Router cum ADSL Modem for my BROADBAND Connection
CRRh8.jpg
This which works fine with normal electricity (ADSL remains static; Even with normal voltage fluctuations)
BUT when power goes off (thank to OUR Power cuts) and home Inverter takes over, the ADSL signal drops periodically in say some 1-2 minute intervals, making it almost useless to use internet (i.e due to constant disconnection and reconnection )

DLINK 2640T comes with an AC 220V to AC 12V 1.2Amp Simple transformer adapter. (This comes from a firm named AMIGO ITE Ltd. and costs friggin 450 bucks. These get burnt if there is a good voltage spike)
My UPS is of PowerCom, single battery OFFLINE type (the normal common ones) which is 10 times better than other normal cheap UPS brands at my place
(I hope people replying know whats d difference between offline and online)


After lot of testing, i have come to conclusion that its the INVERTER issue. Even though the inverter i got is of a good brand (Good quality SINE WAVE one (microcontroller based)), i feel the voltage still fluctuates more than normal for modem to keep the adsl signal static)


My Options:
I read all over internet regarding other people having such issues: and there were few reasons and solutions provided
Few thread were:
http://www.techenclave.com/broadband-forum/adsl-modems-wifi-router-modem-123281/
http://www.thinkdigit.com/forum/hardware-q/70446-how-can-i-connect-my-modem-power-supply-molex-connector.html

Options were
1) USE SMPS based 12v Yellow output and put that DC input into Modem. Given the fact that it has a rectifier built in, DC will pass as such and only requirement amount i.,e 1.2Amp would be withdrawn.
Also as i had GOOD quality (Costly Cooler master SMPS), the quality of supply would be good (interference; noise etc would be less)
BUT When i did that, the ADSL drops regularly in both normal electricity & inverter feed

I tried measuring voltage levels in both Normal Electricity & Inverter Feed in both 12v DC Output SMPS Molex & 12V AC Output DLink Adapter for finding a reason.
Normal Electricity FEED CASE
SMPS -> 12.3
DLINk Adapter- > 13.8

INVERTER FEED CASE
SMPS -> 12.2
DLINk Adapter- > 11.9-12.0


- There is indeed higher range in Adapter case & pretty constant in SMPS case (As expected)
- Further voltage is higher than 13V in DLink adapter normal electricity case, i.e the only time when the ADSL doesn't drop. Does that mean Static ADSL needs 13V to work. Inverter Voltage never came close to 13v
Is voltage the reason here? Guys having good electical knowledge kindly help?
Further is there any way, i can increase the voltage at molex end from 12.2 to 13.2V or something like that...using some resisters, etc ..just to check (Sorry i have forgotten quite a physics now)

2) USE SMPS based wall adapter which is not linear like default dlink adapter and switched mode will correct the issue.
http://www.thinkdigit.com/forum/qna-read-only/86194-dlink-glb-502t-problems.html
here a guy used some oswal adapter and i was never able to find any for 9v even,,,forget the 12v.

Anyway, as people have told that as long as amperage is not less than the required (can be higher) and voltage is same, i can use any adapter.
So to check whether these smps based will work, i plugged in my TATASKY 70-240V AC to 12V DC 2.5Amp SWITCHED mode adapter.
In this case, ADSL dropped even with normal electricity feed.

I searched online but never found any 220V Ac to 12v AC or DC 1.2Amp SMPS adapter.
I found a 220V Ac to 12v DC 1.5Amp SMPS adapter but i am not sure whether that will work (Seller also not sure) . I may be just spending on useless adapters.

3) Use a stabilizer.
Well only one person online said so, i tried, using a AUTOMATIC 0.5 KVA Stabilizer, the same we use with our refrigerators.
ADSL constantly dropped on INVERTER feed as before.


WHAT NOW?
Few things to be noted here:
- Firstly, given the fact that there is no issue at all with my adsl signal when there is normal electricity completely rules out any issue with my adsl line or SNR ratio and other stuff.
- Some people also talked about other things providing interference to modem line. I tried removing landline wire & modem to an isolated place and then checking things. Same adsl drops on inverter.
- Secondly, of course i don't plan to change my INVERTER, just for the sake of testing my adsl ****. So not an option. Going to other people's places to find out is fine but very few have adsl broadband
- Thirdly, i am really at wits end to halt my online activity due to constant power cuts and load shedding . One can plan power cuts and work accordingly but this load shedding ****s a load on everything else (of course ADSL drops here)
- Also does this has anything to do with INVERTER's earthing?
- Interesting thing i found out is, during the early 5-10 minutes of power cut, the ADSL doesn't drop. After that time, it starts dropping regularly as explained at top. Is that pointing to the fact that early on inverter is fully charged or something and provides better voltage? Any other equipment used at home with inverter works fine all the time.
- Also pertinent to mention here that ADSL signal is fine with UPS supply when normal Electricity feed & Inverter is turned off. That gives me an idea that ONLINE UPS (no relay based stuff) will prolly solve the issue. I need to cross check though as a good brand ONLINE UPS like of APC would cost me >600 USD (30000INR)
- Kindly share your thoughts or experiences . also help me find the solution. I am really feeling desperate due to this.

I am new to post here and but i promise i will reply INSTANTLY.
I am trying to ask this on various forums too.
Edited by dlinkman - 6/29/12 at 4:08am
post #2 of 7
Thread Starter 
Anyone can help?
Its been 2 days waiting
post #3 of 7
What do you mean by inverter? You mean a UPS connected to the house or to the router?

Either way. The issue is converting DC into AC. It's not as easy as AC to DC. DC to AC takes quite a bit more work and you still don't end up with a proper sine wave. So some electronics get cranky with this conversion.

4dabd3c6_Inverter_Wave_Comp.jpeg

AC is the perfect sine wave, after a UPS or "inverter" performs work we end up with the square wave. THEN your little wall-wart is turning that "AC" back into DC for your router. You need a SMPS. I did a quick search on eBay and found SEVERAL adapters that would work for you.
    
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post #4 of 7
Thread Starter 
Well, just to clarify
When i say inverter, i mean a backup home power source (which converts DC to AC) Often used in many countries (serves purpose of a generator) where power supply is erratic or poor.
Details
http://en.wikipedia.org/wiki/Power_inverter
E.g http://www.amazon.com/Sunforce-11240-Inverter-Remote-Control/dp/B000WGNNUQ (mine is different)
My model and brand is though not a international one but a reputed brand and probably a sine wave interverter. I am not 100% sure though

So Setup is like.... PC and modem load goes to UPS sockets (UPS is of very good quality and brand), which is plugged into a wall socket, which is powered by a inverter. When MAINS power goes off, inverter switches over and back to main supply when it comes back again

When you say "You need a SMPS.",, do you mean Switched Mode Power adapter for my modem? or something else?
Bcoz as detailed before, i have already tried using 12v DC of a molex connector of my SMPS (Coolermaster 500W model) and adsl signal LEd drops continuously (even with mains electricity)

if you are still not gettin my issue, have a look at another forum , where i also posted the same issue (though sans solution)
w w w . doityourself.com/forum/computers-peripherals/473973-modem-adsl-link-issues-need-solution-ac-dc-guidance.html
w w w .doityourself.com/forum/computers-peripherals/473975-can-i-use-12v-ac-1amp-adapter-modem-requiring-12v-1-2amp.html
post #5 of 7
If you're still getting drop outs with a switched power supply, you need to check your inverter with an oscilloscope.

I am quite aware of what an inverter is an how it functions. I am an electrical engineer wink.gif

How is the inverter powered? via generator? What is the load like? What is it's capacity? Are you running induction type systems off your inverter as well? Resistance type?

There are about a million things that could be causing this. I'd start with the inverter.
    
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post #6 of 7
Thread Starter 
Like i said i have been discussing details at this link
doityourself.com/forum/computers-peripherals/473973-modem-adsl-link-issues-need-solution-ac-dc-guidance.html

Not sure u like browsing other forum links too...but i have posted a alot of details there. Kindly have a read
Overall i think the reason is modified Sine wave of that inverter (not that new model) & in less chances may be even a bit low voltage output from inverter (or voltage fluctuation too)

Inverter is powered by DC battery (lead acid) and supplied power to a fan and light in each room plus few sockets (its a 800VA Inverter ad per rating)
I am not sure what are "induction type systems" and resiative types which you mentioned.
I just put all my computer load +modem's power supply ...on my UPS (12V 7.2 Ah battery). ...and this UPS is plugged into one of those inverter sockets. Whenever mains is ON, mains supply goes to UPS..and when it goes over, inverter supply takes over (switching)...and thats when ADSL signal LED Starts dropping periodically.

(Given the fact that, when inverter is switched off (and mains is off too)... UPS supply is liked by ADSL and there are no such drops..so UPS is nowhere the issue)

The issue is surely inverter...mostly its MSW wave thing or may be a bit low voltage than 12V or even voltage fluctuation (thats probably what MSW is)
I am still waiting to check with a Pure sine wave one!

Thanks for reply.
post #7 of 7
Thread Starter 
Just in case, (i know its long)
at last i think it was not-exactly-a-pure-sine-wave issue with the invertor.
I anyway changed the ADSL modulation to ADSL (Multi-mode) instead of ADSL2+(Multimode) in my Dlink modem settings...which solved the ADSl signal drops.
Though this wont be useful to a person having >6(?) mb/s adsl connection as ADSL only wont support those high speeds.
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