Help! Speaker System Possibly Dying, Need Replacement

[Phris]

Recently, seemingly after I took the time to remove some dust from my computer case, my main speaker setup has been producing loud pops, both when I turn on the amp and randomly over time (generally come in pairs). For a time it seemed like just the left speaker (with them behind me, it is hard to tell), but the right speaker pops loudly when the amp is turned on.

The setup is a Sansui A-505 receiver/amp (ancient, I know) driving "Ultra Acoustic Systems" 300 Series speakers. Together, they sound oddly fantastic, as I've had many friends confirm. They're driven through a computer via a 3.5mm to RCA cable. Right now, I've got them running through this cheap Panasonic amp I picked up at a garage sale to see if they still pop (buzzing, no popping thusfar, but I'll update as I listen more) that barely can drive them properly and generally sounds like crap.

Oh, and the green output jack on my motherboard doesn't output to the left channel unless you twist the cable just right.

So, what I'm looking for is some help as to what is wrong with my system, with hope that I might be able to restore it back to its former glory in the next month (before I leave for college). I would cap the budget hard at $400, and that's only if absolutely necessary...I'm hoping it's merely the receiver/amp.

Thank you. Below are pictures:

Sansui A-505 Integrated Stereo Amplifierhttp://img508.imageshack.us/img508/4166/img6775large.jpg
Speakers Possibly from a white van? I got them from my grandparents; the clarity is exceptional and they can get loud, easily, and keep it clear.
Closeup of Speaker Specifications
POS Panasonic Amp

 

[PM650]

Did you try inducing popping by wiggling connectors? Honestly it sounds like dirty pots/switches to me; cycle all knobs back & forth several times (same for the switches) - this is a frequent procedure you should accustom yourself to if you intend to own older stereo equipment for any length of time

 

[s44]

I'd definitely say it's the receiver. Unless all that popping has added up to speaker damage...

 

[Phris]

It's only been popping for maybe a week or two now, and even then, during a four-hour or so listening session, the speakers only pop maybe three, four times (one of which was during the initial power-on of the amp, which I solved by switching the speakers off until the amp was fully on).

Hopefully it's not speaker damage, there's no way I can afford to replace both. The slight static coming out of the speakers does have a much harsher tone than before; usually it was just that soft hum.

 

[mmntech]

Actually, the pop when you first turn the receiver on is pretty normal for older amplifiers. I have a Pioneer SX-525 from the 70s that does this.

 

[Phris]

It wasn't very pronounced before (a soft thud); now it's a loud POP.