Modem keeps rebooting, every now and then

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avi

avi

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I have very old BSNL WA3002G4 modem. The adapter which comes with it has a rating of 12v 0.7a. Few months ago adapter started giving problems and my modem would reboot simply. I had another spare modem adapter and I started using it with it. Its rating is 10v 0.5v. Earlier I did not know I shouldn't be using devices with different voltage supply. However as modem was working fine I did not bother much.

Fast forward 4 months. It starts rebooting again and again. There is no fixed pattern. Sometimes it would run for days without any problem and sometimes it would start rebooting for every 5 minutes. When I googled, I found out I shouldn't be using different power rated adapter at all. Then I bought a new adapter from ebay with rating 12v 1a. Now with this damn thing, the modem wouldn't even start properly. As soon as DSL stables, it reboots before even it could connect to internet. Now I am back to using old adapter (10v one).

Meanwhile I bought my friend's adapter, he has same modem. Now the modem is working fine.

What to do? How do I solve this issue? Is something wrong with my modem? or do I have to buy another power adapter?
 
^local electronic shop adapter was faulty. no good shops here. so had to buy online :(

I will try with the IC.
 
@avi some old BSNL modems had 12V AC adapter (i,e power going to the modem was AC). So check that.

vivek.krishnan said:
just wire a LM7812 IC in series with your current 12V 1A adapter to see if the issue gets solved
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This will not work. The 78XX series regulators need about 3V headroom. So you will need at least 15-16V input to get 12V output from 7812.
 
^^ why buy such cheapos for complex electronics? i have around 20 of similar types for my LEDs... they keep blowing off every now and then.
 
gauravH said:
^^ why buy such cheapos for complex electronics? i have around 20 of similar types for my LEDs... they keep blowing off every now and then.
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Then, I am at a loss as to what to tell him to buy. I would suggest a SMPS type adaptor, but he does not get them there. He bought a adaptor online, did not work. He can buy a high power 12V 5A adaptor like mine - cost me 500 odd bucks - but too pricy.

Anyone has suggestions as to online adaptop purchases, should please post. I buy my electronics stuff offline. Lamington and my local chap. No issues till now with either.
 
If the modem is switched on only when the PC is switched on then one of the 12V supply lines (black/yellow) from the PC SMPS can be used to power the modem.
 
Keep a point in mind these cheap adapters are not built very sturdy. Most probably they are unable to supply the current demand of the modem and becoming hot and getting fried. So, it will be safer to go for one with higher current output but NOT voltage. This time you can try a 2A adapter and see.
Else get hold of a local TV repair shop and ask him to build you one using transformer and 7812 regulators. If supply voltage in your area doesn't fluctuate very much you can even skip the regulator. Just get a good quality transformer. This will be a little bulky but should last you lifetime.
 
tech.addict said:
Else get hold of a local TV repair shop and ask him to build you one using transformer and 7812 regulators. If supply voltage in your area doesn't fluctuate very much you can even skip the regulator. Just get a good quality transformer. This will be a little bulky but should last you lifetime.
Click to expand...
Sounds good advice, will try this.. thank you!!
 
I just ordered TP Link 8968 after my modem started to give me problems lets see how it goes
 
LAN as in lan cable ports' light?

I have no idea. As long as u keep a cable connected, it'll blink. You remove the cable, it'll stop blinking.
 
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