Repair a PolkAudio psw111 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 8th September 2014, 05:11 PM   #1
diyAudio Member
Join Date: Oct 2012
Question Repair a PolkAudio psw111

Hi all
A friend brought me an amp'd subwoofer psw111 (120V) to repair and use in France (230V).

I checked some power supply input components and replaced the dead ones I found. Unfortunately the fuse still flashes when I power up (with his 230/120v transfo )... So I decided to remove all this main supply to make room, but I can't guess what the value was. Please any advise?
What I can say is the following:
8 inches speaker 4ohm
The unit is rated 150Wrms in specs
Main fuse was 1.6AT
Main caps for the audio power stage are one 470F/63V for each half-wave.
Power audio transistors are 1 IRF640 for one half-wave (not really sure for the second half-wave as I didn't removed the fixation part, maybe a 9640 if exists).
The preamp was suppied from a single separated coil from the mains transformer to make +/- 15V (mono alternance 2 diodes rectifier + 7815 7915 TO220).

I already tested the preamp which is ok with a 20vac xfrm, but now I reach my skills limits so I can't figure the rating of a suited main xfrmr.
The original power suppy was a cheappo pwm and the main secondary power coil was with a central connection for the ground, and rectified with 4 bigger diodes MUR420).

Thank you for tips

[EDIT]: my error: maybe the amp is not a class D. I can't see the specific snubbers and LC output filter on the PCB . Please admin, move the post to the good forum section.
Thank you.

Last edited by HumNSmoke; 10th September 2014 at 06:25 PM.
  Reply With Quote
Old 22nd September 2014, 12:46 PM   #2
diyAudio Member
Join Date: Oct 2012
I reached to test the power amp with two 500VA 220/2*50Vac transformers I connected in series to get a 2*25Vac power supply which gave me 2*~36Vdc.
It works, although with some noticable hum, maybe from the huge toroids near around.

Please do you think I could buy 2 PWM 48Vdc or how could I calculate maximum voltage & minimum amperes. This subwoofer was specified 150W rms and the LS is 4 ohms.

  Reply With Quote
Old 22nd September 2014, 01:22 PM   #3
diyAudio Member
Join Date: Oct 2012
I just had a look here : The Signal Transfer Company: Power Output

from this:
Assuming I'd like to use DC supplies:
P=U^2/R, U=(PR)^(1/2)=(4*150)^(1/2)=24V

So I'd need 2 24Vdc 150W supplies?

  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Polk Audio sub PSW111 michaeleanor Subwoofers 3 27th September 2014 01:53 PM
Wharfedale 10.7 or Polkaudio TSi500 Junie Multi-Way 14 7th July 2013 05:20 PM
Is a repair possible? seebert Multi-Way 9 6th October 2011 06:27 PM
Polkaudio? steven123654 Car Audio 2 30th August 2009 04:54 PM
sub repair...need help ! artie in miami Subwoofers 1 10th April 2009 06:55 PM

New To Site? Need Help?

All times are GMT. The time now is 05:14 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2