PSW202 Amp not working properly

CrazyBoy

Hi,


My PSW202 stopped functioning well, it sounds like it's coughing..I was told it's the circuity when I took it in for repair. Reading posts on the internet I noticed that this issue might be caused by 2 capacitors which were of the
wrong value / faulty design and that Polk Audio would replace these under warranty even if the unit is out of warranty, does any of this make sense?

Thx

Tbone289

Yes, that makes sense, and Polk has been known to do that repair out of warranty. I've fixed a couple of PSW202's with the same issue, both out of warranty, and Polk mailed me the parts without any questions.

If you contact them, they will request that you remove the amplifier from the back of the unit and ship it to them for repair. They replace the capacitors with the proper values (higher voltage) and replace the amp chip that the original capacitors may have damaged.

CrazyBoy

Thank you for your reply, looks like Polk doesn't wanna go out of their way to accomodate me since the sub has been discontinued for quite some time

Does anybody know which capacitors were to be changed and what value? I can make the swap myself since I studies in electronics, mind you has been a long time..

Tbone289

Sorry about that. I didn't mean to get your hopes up.... It has been a number of years (8-10?) since the last one I repaired.

I'll try to pull the amp out of mine this weekend and take pics, and give you the details... As you can see from my signature, I believe the PSW-202 is worth saving (still happily using one). It was replaced by the PSW10, which IMO is an inferior product, especially for music.

The repair is an easy one, especially if your amp chip is still good. Don't spend too much on this repair though, since you can get a used replacement very cheaply.

Tbone289

I found a pic for you! here: http://www.polkaudio.com/forums/showthread.php?9766-PSW202-mods&p=91962&viewfull=1#post91962

What you see there is a PSW202 with the woofer removed. At the back of the box, you can clearly see one of the caps to be replaced at the upper right corner of the plate amp. The other cap is right next to that one, behind it in the picture.

Pull the amp and look at those two caps. You will want to replace them with the same farad value, but with a higher voltage rating.

CrazyBoy

Hi!

I know this is several years old but i just finally had time to get to repairing it. Would anybody by chance have pictures or instructions on the repair?

Thx

Tbone289

Let me see what I can find. I'm still using my 202, so if I can't find a picture, I might just take one for you.

Tbone289

Jackpot! See this discussion:

http://www.electronicspoint.com/threads/help-with-replacing-component-on-circuit-board.262029/

The two 4700uf caps in the 4th picture are what you need to replace. You might also need to replace the amp chip that is discussed in the link. I replaced the chip while I was in there, but didn't bother to test to see if the old one was stilll good.

CrazyBoy

Thanks Bud, Appreciate it! I will work on it and report back!!

Alberto_Gonzalez

My PSW202 died and now is out of garanty. I am wondering if I can request the amplifier update of the capacitors. I have sent the subwoofer to the Service Support in Spain located in Madrid. Please, let me know if they can request this update and if I have to pay for it. Thanks.

Alberto_Gonzalez

More info from Official Polk Support in Madrid. This is the budget for reparing the subwoofer. They are including 2 capacitors of the wrong designed voltage, 35 v, one fuse, one rectifier and something called "pastilla" and 1,5 hour labor. I do not know if the amp chip is included.

I think that the reparation price,132,45€, does not worth for a subwoofer bought in 2005. Any recommendation?. Thanks in advance.

jabob2787

I know this thread is older, but it got revived back in March. I have a PSW202 that was given to me because the owner though he blew the speaker. The initial diagnosis was the speaker was making a crackle on every hit of the sub. I determind that the speaker is working properly, which led me here. It had 35v caps that i replaced with 50v. Now when i plug it in it keeps blowing fuses. Could the amp chip also be bad? The chip showed no signs of heat, cracks, etc. So the only thing i have is blowing fuses. Any input would help. Thank you. How can i test to see if the chip needs replaced? I'm not at all opposed to replacing it though.

[Deleted User]

Hello,
Welcome to Polk's forum. In all likelihood the "STK" amplifier needs to be replaced, you can check pin 7 to pin 6, and pin 7 to pin 8 which should be the output transistors.
If there's no short circuit or low resistance measurment it should be alright.
Most of the time it's easier to just replace it.
Regards, Ken

jabob2787

The STK amplifier is the chip at the top of this picture, correct?

[Deleted User]

That is correct, I found this link:
http://www.electronicspoint.com/threads/help-with-replacing-component-on-circuit-board.262029/
I hope it is helpful.

jabob2787

Awesome thank you thank you so much for your prompt replies!

[Deleted User]

You're welcome, good luck with the repairs.

Junda

Hi i have a PSW 202 subwoofer that does not light up or turn on anymore. before it completely spoiled, it would randomly make low frequency sounds and i have to go to the main power output and turn it off to stop the noise. I was listening to some music when out of a sudden the subwoofer started crackling and kept giving me poping noises before giving me one last loud and low humm and stoped working after that. I saw a video on youtube where a guy replaced his polk audio subwoofer's circuit board that you guys mailed to him. Btw i live in singapore and there are no service centers or anything... im unsure what i should do so pls guide me through thanks

https://www.youtube.com/watch?v=QOxdwpGlcvw

[Deleted User]

Hello,
Welcome to Polk's forum. Let me find out who, in Singapore would be best to contact.
Regards, Ken

[Deleted User]

Hello,
The company who you should contact is Unicorn and their website is: http://unicorn-elect.com/
I hope this is helpful information.
Cheers, Ken

CrazyBoy

Hi T-Bone, hope all is well

I opened the sub / reviewed the caps and they don't seem blown. The "STK" amp does not look cracked either, should i just change the caps and try, also what value / voltage should i get the new caps?

Tbone289 wrote: »

Jackpot! See this discussion:

http://www.electronicspoint.com/threads/help-with-replacing-component-on-circuit-board.262029/

The two 4700uf caps in the 4th picture are what you need to replace. You might also need to replace the amp chip that is discussed in the link. I replaced the chip while I was in there, but didn't bother to test to see if the old one was stilll good.

CrazyBoy

Or should i just change the caps and the transistor anyways?