psw-200 woes

Bill R
Bill R Posts: 8
edited December 2010 in Troubleshooting
I haven't listened to my psw-200 in quite some time. The other day I decided to fire it up and noticed that the unit was left turned on. The red led was out and she was dead. I opened the sub up and found a blown fuse and 2 bad resistors. I replaced the fuse and tested the unit for the hell of it. I get the red led, but nothing else (as I suspected with the fried resistors). Where do I go from here? I have elementary soldering skills, and a practice pcb to brush up my skills, but I'd like to know if you guys think I may have done other damage. The board itself appears to be fine.
I can post a pic if it will help.
Thanks for any help or advice!
Post edited by Bill R on
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Comments

  • GZ
    GZ Posts: 343
    edited October 2003
    If you do decide to do any soldering on that circuit board make sure you use a solder heat sink.
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  • resinator
    resinator Posts: 1
    edited November 2003
    snip
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  • Bill R
    Bill R Posts: 8
    edited November 2003
    Polk won't support this unit at all. They can't even provide me with the resistor values because they don't have the print in their records. One resistor is toasted to the point that I can not identify it's color bands at all. Is there anybody that can help me?
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  • [Deleted User]
    [Deleted User] Posts: 7,658
    edited November 2003
    Hello Bill,
    Thanks for participating in the Forum. If you'll send me your US Mailing address I can send a copy of the amplifier's schematic. We don't have replacement individual parts, we purchased the amplifier as a complete unit. However, most parts are relatively common. You may email me at kswauger@polkaudio.com or telephone me at 1-800-377-7655 extension 891.
    Regards, Ken
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  • Bill R
    Bill R Posts: 8
    edited November 2003
    That's exactly what I'm looking for.

    I sent you my info.

    Thanks!!!
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  • [Deleted User]
    [Deleted User] Posts: 7,658
    edited November 2003
    No problem!
    Regards, Ken
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  • Bill R
    Bill R Posts: 8
    edited November 2003
    I'm having a heck of a time identifying the two resistors above the toasted one. They appear identical. The schematic says they are 4.22K .... they read 3.03K and 3.01K on my meter (although they may have been damaged) ... and I can't make heads or tails of their color bands. The third one from the scorched resistor is a 10K .. its color bands make sense, and it reads 6.17 K on the meter. Every other resistor on the board is coinciding with the readings/colorbands and schematic.
    Can somebody decipher the value(s) of the resistors above mr. charcoal?

    thanks
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  • Bill R
    Bill R Posts: 8
    edited November 2003
    Well I've replaced the four resistors in question here and no luck. The transformer and rectifier voltages seem fine. I'm out of resources. Looks like another psw200 amp plate for the boneyard, unless somebody here can help.

    Bill
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  • Bill R
    Bill R Posts: 8
    edited November 2003
    I know, I know ........... "Go buy a new sub, you cheap bass ****."


    Well, I thought fixing it might not be too difficult. Man was I wrong.
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  • Tour2ma
    Tour2ma Posts: 10,177
    edited November 2003
    Bill (AKA "cheap bass ****" :) ),
    I take it you've had a few more phone conv's with Ken?
    Do you think it's a matter of not finding exact replacements for the resistors?
    BTW, I've found that results do vary if tested components are on a board due to other paths in the printed circuit....
    More later,
    Tour...
    Vox Copuli
    Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb

    "Death doesn't come with a Uhaul." - Dennis Gardner
    "It's easy to get lost in price vs performance vs ego vs illusion." - doro
    "There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD
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  • Bill R
    Bill R Posts: 8
    edited November 2003
    No Tour2, I haven't given Ken a shout back. I thought he would just chime in on this thread if he could assist me further. To be honest, I had to use lower wattage resistors in place of the bad ones, and I really don't have the knowledge to troubleshoot the rest of the circuit board.
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  • johnnyrawhide
    johnnyrawhide Posts: 6
    edited December 2003
    i'm in a similar situation as you bill...
    have you made any progress? my psw-200 has just been sitting for weeks while i try to find the time to either attempt a repair or get enough money to replace it. i'd love to hear about how you're coming along.
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  • Bill R
    Bill R Posts: 8
    edited December 2003
    Hi Mr. Hide
    I'm not making out very well. I've pretty much thrown in the towel. The schematic Ken sent me is good, but I have to admit, electronics are a bit out of my league ... my electrical knowledge is geared more toward industry. I'm not sure if it would be worthwhile to take this board to a repair shop ..... any ideas?

    You have checked/replaced the fuse .. right?
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  • johnnyrawhide
    johnnyrawhide Posts: 6
    edited December 2003
    yeah, i replaced the fuse a while back. but when i powered up the sub i got constant hum out of the woofer indicating that there is a short of some sort i guess. (this happens with no input to the sub, as well as with input from a known good source). i figure that tinkering will be a lost cause but i'm definitely willing to give it a go. you never know till you try right? ;-)
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  • Tour2ma
    Tour2ma Posts: 10,177
    edited December 2003
    jrh,
    Hum could be due to an external issue.... House wiring... RFI from an appliance... etc.
    More later,
    Tour...
    Vox Copuli
    Better to remain silent and be thought a fool, than to open your mouth and remove all doubt. - Old English Proverb

    "Death doesn't come with a Uhaul." - Dennis Gardner
    "It's easy to get lost in price vs performance vs ego vs illusion." - doro
    "There is a certain entertainment value in ripping the occaisonal (sic) buttmunch..." - TroyD
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  • mikeinaustin
    mikeinaustin Posts: 12
    edited December 2003
    humm/buzz is not the result of external sources, but of a "failed" amplifier in the psw-202. i own two of them, one died about a month ago (constant buzz and no audio), polk replaced. now the second one has just died with the exact same symptoms (humm/buzz).

    in both cases, no hard audio was put through units, just am talk radio (football game announcers). is there a fundamental design flaw with these units?

    on the previous unit it looks like they changed out the two large capacitors, but can't tell what else they did. anyone have the schematics to these psw-202 amplifier boards? if so, please send to me so i can look at failed unit and compare with good unit.

    please email them to mikeinatexas@yahoo.com if you do have the schematics. it'll save me the cost of shipping the dead amplifer back to polk.

    now i will say this, i have owned polk products all the way back to the old monitor 5's (these are still my main speakers) and this is the first problem i've ever had. but to have both subwoofers go bad, this is a very bad sign.
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  • mikeinaustin
    mikeinaustin Posts: 12
    edited November 2007
    well crap, one of my psw-202 has failed yet again. anyone have a clue why these subwoofers fail so often????
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  • RuSsMaN
    RuSsMaN Posts: 17,987
    edited November 2007
    4 years later - so often?

    Contact Polk Customer Service directly, the 202 is oop for a few years now.
    Check your lips at the door woman. Shake your hips like battleships. Yeah, all the white girls trip when I sing at Sunday service.
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  • Course Rider
    Course Rider Posts: 5
    edited January 2008
    If you still need help with your PSW200 amp I can help.
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  • JCMears
    JCMears Posts: 2
    edited January 2009
    I had the same problem, diagnosed the shorted power MOSFETS in the output section, then started tracking the other active components. There's a recommended update to the zener diodes that bias the output section. I managed to get a schematic from Polk that noted the zener update that's required to reduce the risk of the MOSFETS blowing. Then I tracked the original amplifier to Triad, and they sent me the actual testing procedure for the amp, along with a better, annotated schematic. BUT THEN, they happened to be doing inventory, and found a BOX OF THE ORIGINAL ASSEMBLED CIRCUIT BOARDS FOR THE PSW200, and offered to sell me one. $30 "as-is", but it saved me a lot of testing and component replacement, which is worth it. Here's the caveats and contact information from Brent Passmore of Triad (the OEM for the amp):

    "I have not counted them but we have something like 15 to 20 of those amp boards on hand. You can put that info on the forum but with the following added.

    The boards are new but would be sold “as is” with no warranty. Also they will need to find a local repair shop to do the work. I will include the instructions and schematic with the boards so their repair shop has all of the info we have to do the job.

    It just is not worth our time to do the repairs here and then have the hassle of warranty if something goes wrong again down the road.

    Brent Passmore
    Service Technician
    Toll Free: (877) 264-6315
    Direct: (503) 517-2668
    Fax: (503) 517-2631
    Service@TriadSpeakers.com

    Triad Speakers, Inc.
    15835 NE Cameron Blvd.
    Portland, OR 97230
    www.TriadSpeakers.com "

    Hope this helps, it took me a lot of work to track this down, but I wasn't willing to trash an otherwise good subwoofer....
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  • abel
    abel Posts: 3
    edited December 2010
    Hi JCMears.
    Question.
    Did they actually mailed you or e-mailed you the testing procedure and the annotated schematic.Thank you in advance for your reply.I'm having the same problem.
    Abel.
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