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5.1 Ultra - Loud Humming - Control pod or amp?


DonnieZ

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  • 2 weeks later...

I replaced the 100mF caps with the Digikey ones that Habersham referenced yesterday and now my setup is hum-free. I'm thinking that the fact that the new caps are designed for higher heat levels and are smaller than the originals may prevent the issue from reoccuring. Thanks all for your help.

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  • 2 weeks later...

I'm glad I found this thread. I've had my trusty ProMedia 5.1 THX (non-Ultra) system for many years. The Sub died in 2008 and I sent it in to some 3rd party guy in Texas I found via google search. He repaired it and it worked great until a few months ago. Now I too have the HUM problems.

1) Are the Caps I needed to replace on my non-Ultra 5.1 (original 5.1) the same problem as described here? Sometimes I only hear the hum out of the subwoofer, and sometimes I hear it out of the regular speakers. You can hear it even when NOTHING is plugged in, and volume has no effect on the level of hum. This thing is in my bedroom so it needs to be quiet. I mostly use it hooked up directly to my Apple AirPort Express for instant music.

2) I've also had a problem with my control pod. When I turn the digital control knob, it doesn't respond smoothly. For example, as I turn the volume up, it will sporadically jump up and down at random. It will eventually get to where I want to go, but pretty annoying. Any suggestions how to fix that? I took the screw out the back of the control knob, but can only unclick half of the plastic clamp pegs. (bottom half refuses to come off) I was hoping I could clean the contacts or make some adjustments. I've also setup an alert for when a control pod for the non-Ultra becomes available.

What is the dif between the THX(non-Ultra) and Ultra anyway? (quality wise)

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  • 3 months later...

I have the ProMedia 5.1 humming/buzzing issue when I power on, regardless of speakers attached and I've tried numerous outlets and power cables. When switching to "HP" (headphone mode) I do not get the buzzing. When speakers are plugged in, they hum too. Sub hums regardless unless HP is enabled on control unit. Having said that, I hope this post resolves my issue!

I took amp apart by taking out screws along the orange line surrounding the back plate. I then took the unit out, unplugged the sub +/- leads, and examined the board. Attached is a picture of the 100mFd 35v caps referenced in the post, I believe.

Please confirm this is correct and I will proceed going to Radio Shack! I've done soldering before, the space is tight but do-able. Thanks again and I hope it resolves my issue!

post-57567-1381980004713_thumb.jpg

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  • 7 months later...

Just wanted to say a huge thank you to stpete for the diagnosis, habersham for the parts, and everyone else for the pointers and pictures. Fix took barely 20 mins and completely knocked out the background hum that has been plaguing my existence for the past month. Going on 12 years with these speakers, so glad to have them functioning perfectly again! Thanks!

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  • 2 months later...
  • 6 months later...

I created an account just so i can thank Stpete Cooling for the fix, it worked for me!

I have the 5.1 ultras and had the hum/buzz come from the base unit and speakers. I unplugged the speakers and audio source, just leaving the controller and power and still had a load hum that stayed the same db regardless of volume control. I replaced the two capicitors that Stpete Cooling identified and that are in pictures StevenWithaV's posted and it worked. I do not hear any buzz/hum even at high volumes. I love my speakers again!

I had never soldered anything before this project. It's difficult to get to but if you take your time and maybe practice on a few old boards, i think anyone can do this project.

Thanks again.

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  • 2 months later...

My AMP started humming last weekend. It was really loud. We replaced the two 100uf 35v caps and while it drop the humming down a lot, it still hums and no audio will come out (headphones work fine in control modual)

What other CAPS should we replace? Please help!

thanks,

jon

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  • 5 months later...

I am another camper who registered on these forums only to thank Stpete Cooling for his advice. After a quick trip to Radio Shack for the capacitors and about 30 minutes of work I am once again enjoying the sound of the best computer speakers I have ever owned. NO MORE HUM!!!

 

Thank you StPete.

 

On another note....I still have an audible hissing. It's not really a big problem when playing loud music, but at higher volumes and when there are quiet passages or no music playing, it is quite annoying. Any tips for this one, Pete?

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  • 1 month later...

Been a long time since I posted here but my Klipsch Promedia Ultra 5.1's got the loud hum a couple of years back and I just switched to the Klipsch 2.1 set I also had. Just no time to look at it. So the Ultra'

s have been setting in my storage area for a long time just waiting for me to look at them.

 

Well I picked up two 100uf cap's from Radio Shack and my Klipsch Promedia Ultra 5.1's are as good as new!

 

All good again!

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  • 4 weeks later...

I just now joined the Forum to say thanks to all who've posted in this thread.  I'd been putting up with the super-loud hum for far too long... until today.  After reading the previous posts, I grabbed a soldering iron and two 100uf 35v 105deg capacitors from Fry's Electronics.  First time I ever soldered anything, and it's a success!  The hum is totally gone - I'd forgotten it could be like this  :) 

 

The only real issue I had was with removing the capacitors.  I'd de-soldered as best as I could, and straightened out the tips poking through, but could not pull the capacitors free from the board.  I eventually pulled the capacitors completely off of their pins, with the pins still stuck to the board.  After that, it was a simple matter to de-solder the newly exposed side, immediately pulling the pins free.  Attaching and soldering the new capacitors (noticeably smaller than the originals, huh) was pretty uneventful.

 

Thanks everyone!

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Hi guys!  I just found this thread.   I am having the exact same issue with my Promedia 5.1's.  I've had them since 2003 and I love them!  I will open the sub up when I get home to check those capacitors. 

 

One question.  I do not have any soldering gear and I haven't soldered anything in probably 15 years.  What should I buy to get this job done?  

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  • 5 weeks later...

Hey everyone,

 

I had to replace the BASH chip about a few years ago, so I thought this hum was the final blow for me to toss my 5.1 Ultras out...

 

But hey, I signed in and wanted to thanks! I've had the hum in my 5.1 Ultras for a while. I found this thread about 6 months ago and bookmarked it for this very day. Went on down to Radioshack and bought up their last two 100uf 35v capacitors. They only had the 85 degree ones, but the old ones lasted a very long time... So if I have to change them again in 10 years, then why the hell not. The soldering job was annoying as the solder points were right at the edge of an adjacent board, so I couldn't really get my solder sucker in there. Instead, I just used the needle soldering iron to melt the solder and left the old solder on there. When I put the new caps in there I added fresh solder.

 

Again, it's amazing. Like others have said, I forgot what it was like to not have a hum! 

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  • 1 month later...

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