gexecuter, there are two other things that affected the 660HW-61 that you can try before having to get into the config:
1) It's susceptible to power blips, it'll go into TTM1. Try and put it on an UPS if you're in an area with supply fluctuations.
2) It's susceptible to heat. Under the middle base it gets warm and then just stops communicating. Either support it at both sides on something, (I use 2 matchboxes - hi-tech, huh), or mount vertically to let air flow and cool it.
Funny that you mention power blips since in my house the power goes out very frequently. Something about the electrical sockets. I wish i could afford an UPS but i can't.
I also have semi-frequent power blips/brownouts, (of course they only happen when I'm not here), as I mentioned above somewhere I also have a PC that's on 24/7 downloading from usenet. So when the power blips, the router could go down and the PC stops downloading until I can get to it to power cycle the router.
I also don't have an UPS, (one of those things I haven't got around to), but I have minimised the effect of power blips when I'm away, (as I will be in about 18 hours for 7 weeks), by doing the following:
1) the router is plugged into a time switch that's set to power off at around 0100 and then power on 15 minutes later - this will get it out of TTM.
2) the PC is set in BIOS to power on at AC restore and
power on at a fixed time every day.
This combination has allowed it to weather 3-4 months of me being overseas without a problem.
Although, if the problem is in your electrical house wiring then you have bigger problems. I have a rental property that kept blowing the controller in the central heating, we thought it was the grid supply fluctuating and had a surge protector fitted to the supply/meter board. It happened again, except power was lost to half the house.
It turned out to be one power outlet in the family room where the wires hadn't been properly secured/screwed in from new, (it was only built 8 years ago). Vibration caused intermittent connection, which caused intermittent surges through that circuit, (which just happened to have the central heating controller on it), and bang.......there goes the controller.
We got off light, it could just as easily have started a fire.
About the heat stuff, i think i could come with something. even tough i can't think of something right now.
Come on, four matchboxes, one at each corner - you only need to raise it about 12-20mm
btw any of those two issues can affect my speeds?
Not that I'm aware of, both my mate and I run the P-660H(W)-61 and these are the only real problems we've found with them. I even bought one for my parents i.l.o. these minor faults because it's features far outweigh them for the price.
However, without knowing how your ISP has set up the config it can't be ruled out that something in there is affecting it, eg. they've turned on Media Bandwidth Management with the wrong settings.
PS: i don't think my ISP would give me router's password because when the tech came to my home he said i couldn't change the Wifi network password or something like that.
Can I ask who your ISP is, (also, have you tried your ISP's name as the password) ?
This is why I really hate having to use 'their' equipment, (which I'm not, but I had a choice), however if you know the username/password and basic settings for the ADSL then you can do a factory reset by, (IIRC), pushing in the button on the back while powering on the router, hold the reset button for 10 seconds then release. The router should go through it's diagnostics and start up with no internet connection, you should be able to enter the config then using '1234'.
Then enter Wizard Setup, you'll need the following info:
Encapsulation: PPPoE (usually)
Virtual Circuit ID:
The bottom 3 values, (Multiplex, VCI, VPI), you need to get from your provider - the ones I've given are a general default.
On the next page:
Service Name: Telefonica (just guessing
Obtain an IP automatically
Connect on Demand Max timeout 7200
You need the 'User Name' and 'Password' from your ISP, the other options can be changed once a connection is established. Once you click Next it should connect, (IIRC).
As I mentioned above, I'm off for 7 weeks shortly so any questions later than about 1800 AEDST today will incur a delayed response