psw404 has low output with the Nak SR4a preamp volume all the way down.

Freddymac

Could it be a left and right summing circuit problem. Is the crossover a 12db/octive cutoff? It acts like the output of the woofer doesn't increase with the Nak SR4a volume control.
Can I get a service manual with schematics? It is not oscillation because it follows the music. I think the pots are also dirty. Do you repair the crossover/amp at the Polk Service center without the speaker and cabinet?

[Deleted User]

Hello,
Welcome to Polk's forum. Probably the first thing to do is determine if the subwoofer is working or not. To do this turn the volume of the sub all the way down and connect the right and left output of a DVD or CD player to the corresponding right and left inputs of the sub. Then start playing a CD and slowly turn the volume up on the sub, you should hear plenty of undistorted bass.
Regards, Ken

Freddymac

Hi Ken,
I am sorry that I did not describe my problem properly. The woofer works, although I would like a complete service manual for a psw404 b or at least a schematic diagram and biasing info. I am new to subs, as I just picked up this one used. I think the pots are dirty and I want to be sure it doesn't have any other problems. What does the B series change over the 404 model. Can I buy a new grill for the 404. How old is this unit? SN 10964
I Also want to know if you make a unit of this quality today? What would the model number be for this size or smaller Sub? It must be reliable!

Thank you
Joseph Merriam

[Deleted User]

Hello Joseph,
I don't believe there's a service manual for the PSW404, however Polk's CS department (1-800-377-7655) should be able to send you a copy of the bass amplifier schematic. They would have information on replacement grills and any other parts availability. In all likelihood they won't know how old the unit is based on the serial number. Here's a link to all of Polk's subwoofers:

http://www.polkaudio.com/Home-Audio-Subwoofers/l/705

Regards, Ken