K.C. Cool

Hey all, I just wanted to follow up. A big thanks goes to @stpeteshepherd for pinpointing my issue with the capacitors on the AC-CD Converter daughter board, as I did fix my intermittent hissing issue! More details below... With this kit being close to the cost of a mail-in repair ($130-$150 depending if you go with the kit or repair), you kind of need to weigh your own cost / benefit / abilities with a system this old. I reached out to @stpeteshepherd and decided to buy his 5.1 Ultra repair kit with a fan. My reasoning for going this route is: I have a beginner's ability to desolder / solder and have repaired this system before thanks to forum members like yourself sharing information. @stpeteshepherd has reengineered 3 components (BASH chips and AC-CD Converter Daughter board) to be cooler and longer lasting which is a godsend for a system this old with faulty parts. I also wanted a kit that had everything I needed to fix my current issue and future issues with this system without guessing, along with instructions. With that in mind, If I knew exactly what to replace, I could have bought some of the components that fixed my specific issue for less than $20, but I will inevitably have to replace/fix something in the future as these systems are prone to breaking due to heat issues. Something keep in mind that as time goes on: less and less people have these systems and Klipsch Promedia electrical enthusiast may not be selling / repairing these forever, so I figured buying now is an investment in the future of these 501 Ultras 😃. At first I sought out to do a full repair and replace everything in the kit, so I tackled the two 16v 100 uF and two 35v 100 uF capacitors at the upper right corner of the panel near the pair of small black heat sinks in the picture attached. Years ago I replaced the 35v 100 uF capacitors due to a bass hum, but I decided to replaced these with the new ones in the kit since they were and upgrade / a higher temp rating. Doing so, I accidentally pulled out a copper trace from the board because I didn't fully desolder. Stpteshepherd even warned me of this in the instructions 🤦🏼‍♂️. Re-attaching a trace is currently outside of my electrical wheelhouse, so I thought I ruined my system. I attempted to solder the capacitor back anyways on the top and bottom of the board and it seems to be working fine, but I'm not sure if this is a permanent fix or not. Due to this FUBAR, I decided to focus on what I believed my main problem was: The AC-DC converter board with the three 22uf 50v capacitors, 2N5551 transistor, and Zener diode on the AC-DC converter board (picture attached). I wanted to focus on this area first as this was the only area where the bottom of the board was charred. After replacing these 5 components and starting the system up again, it stopped buzzing and hissing. Once again, silence! Huzza! Pro tips: When removing the AC-DC board, use needle nosed pliers to grab the plastic mounts under the board and unscrew the screws holding those in place on the outside of the panel. I tried to press the plastic prongs in, but the plastic is so old the prongs broke off 😑. All in all, if you are having this problem and stumble upon this forum post, doing this repair is pretty easy and even a beginner with a solder sucker and a soldering iron can pull this off. @stpeteshepherd also gave instructions in the kit to replace many more commonly failed components and an internal fan kit to keep everything cool. Since my previous repairs are currently holding up (for now...), I didn't attempt to replace anything else in fear of causing more damage than good. I'm sure something will fail down the road, but I have the parts and instructions to tackle them when they come at me 😃. It's crazy to think about keeping these nearly 20 year old speakers going, but they still sound great and are fairly simple to repair. I hope this helps someone in the future!

Hey all, I just wanted to follow up. A big thanks goes to @stpeteshepherd for pinpointing my issue with the capacitors on the AC-CD Converter daughter board, as I did fix my intermittent hissing issue! More details below... With this kit being close to the cost of a mail-in repair ($130-$150 depending if you go with the kit or repair), you kind of need to weigh your own cost / benefit / abilities with a system this old. I reached out to @stpeteshepherd and decided to buy his 5.1 Ultra repair kit with a fan. My reasoning for going this route is: I have a beginner's ability to desolder / solder and have repaired this system before thanks to forum members like yourself sharing information. @stpeteshepherd has reengineered 3 components (BASH chips and AC-CD Converter Daughter board) to be cooler and longer lasting which is a godsend for a system this old with faulty parts. I also wanted a kit that had everything I needed to fix my current issue and future issues with this system without guessing, along with instructions. With that in mind, If I knew exactly what to replace, I could have bought some of the components that fixed my specific issue for less than $20, but I will inevitably have to replace/fix something in the future as these systems are prone to breaking due to heat issues. Something keep in mind that as time goes on: less and less people have these systems and Klipsch Promedia electrical enthusiast may not be selling / repairing these forever, so I figured buying now is an investment in the future of these 501 Ultras 😃. At first I sought out to do a full repair and replace everything in the kit, so I tackled the two 16v 100 uF and two 35v 100 uF capacitors at the upper right corner of the panel near the pair of small black heat sinks in the picture attached. Years ago I replaced the 35v 100 uF capacitors due to a bass hum, but I decided to replaced these with the new ones in the kit since they were and upgrade / a higher temp rating. Doing so, I accidentally pulled out a copper trace from the board because I didn't fully desolder. Stpteshepherd even warned me of this in the instructions 🤦🏼‍♂️. Re-attaching a trace is currently outside of my electrical wheelhouse, so I thought I ruined my system. I attempted to solder the capacitor back anyways on the top and bottom of the board and it seems to be working fine, but I'm not sure if this is a permanent fix or not. Due to this FUBAR, I decided to focus on what I believed my main problem was: The AC-DC converter board with the three 22uf 50v capacitors, 2N5551 transistor, and Zener diode on the AC-DC converter board (picture attached). I wanted to focus on this area first as this was the only area where the bottom of the board was charred. After replacing these 5 components and starting the system up again, it stopped buzzing and hissing. Once again, silence! Huzza! Pro tips: When removing the AC-DC board, use needle nosed pliers to grab the plastic mounts under the board and unscrew the screws holding those in place on the outside of the panel. I tried to press the plastic prongs in, but the plastic is so old the prongs broke off 😑. All in all, if you are having this problem and stumble upon this forum post, doing this repair is pretty easy and even a beginner with a solder sucker and a soldering iron can pull this off. @stpeteshepherd also gave instructions in the kit to replace many more commonly failed components and an internal fan kit to keep everything cool. Since my previous repairs are currently holding up (for now...), I didn't attempt to replace anything else in fear of causing more damage than good. I'm sure something will fail down the road, but I have the parts and instructions to tackle them when they come at me 😃. It's crazy to think about keeping these nearly 20 year old speakers going, but they still sound great and are fairly simple to repair. I hope this helps someone in the future!

Hey all, I just wanted to follow up. A big thanks goes to @stpeteshepherd for pinpointing my issue with the capacitors on the AC-CD Converter daughter board, as I did fix my intermittent hissing issue! More details below... With this kit being close to the cost of a mail-in repair ($130-$150 depending if you go with the kit or repair), you kind of need to weigh your own cost / benefit / abilities with a system this old. I reached out to @stpeteshepherd and decided to buy his 5.1 Ultra repair kit with a fan. My reasoning for going this route is: I have a beginner's ability to desolder / solder and have repaired this system before thanks to forum members like yourself sharing information. @stpeteshepherd has reengineered 3 components (BASH chips and AC-CD Converter Daughter board) to be cooler and longer lasting which is a godsend for a system this old with faulty parts. I also wanted a kit that had everything I needed to fix my current issue and future issues with this system without guessing, along with instructions. With that in mind, If I knew exactly what to replace, I could have bought some of the components that fixed my specific issue for less than $20, but I will inevitably have to replace/fix something in the future as these systems are prone to breaking due to heat issues. Something keep in mind that as time goes on: less and less people have these systems and Klipsch Promedia electrical enthusiast may not be selling / repairing these forever, so I figured buying now is an investment in the future of these 501 Ultras 😃. At first I sought out to do a full repair and replace everything in the kit, so I tackled the two 16v 100 uF and two 35v 100 uF capacitors at the upper right corner of the panel near the pair of small black heat sinks in the picture attached. Years ago I replaced the 35v 100 uF capacitors due to a bass hum, but I decided to replaced these with the new ones in the kit since they were and upgrade / a higher temp rating. Doing so, I accidentally pulled out a copper trace from the board because I didn't fully desolder. Stpteshepherd even warned me of this in the instructions 🤦🏼‍♂️. Re-attaching a trace is currently outside of my electrical wheelhouse, so I thought I ruined my system. I attempted to solder the capacitor back anyways on the top and bottom of the board and it seems to be working fine, but I'm not sure if this is a permanent fix or not. Due to this FUBAR, I decided to focus on what I believed my main problem was: The AC-DC converter board with the three 22uf 50v capacitors, 2N5551 transistor, and Zener diode on the AC-DC converter board (picture attached). I wanted to focus on this area first as this was the only area where the bottom of the board was charred. After replacing these 5 components and starting the system up again, it stopped buzzing and hissing. Once again, silence! Huzza! Pro tips: When removing the AC-DC board, use needle nosed pliers to grab the plastic mounts under the board and unscrew the screws holding those in place on the outside of the panel. I tried to press the plastic prongs in, but the plastic is so old the prongs broke off 😑. All in all, if you are having this problem and stumble upon this forum post, doing this repair is pretty easy and even a beginner with a solder sucker and a soldering iron can pull this off. @stpeteshepherd also gave instructions in the kit to replace many more commonly failed components and an internal fan kit to keep everything cool. Since my previous repairs are currently holding up (for now...), I didn't attempt to replace anything else in fear of causing more damage than good. I'm sure something will fail down the road, but I have the parts and instructions to tackle them when they come at me 😃. It's crazy to think about keeping these nearly 20 year old speakers going, but they still sound great and are fairly simple to repair. I hope this helps someone in the future!

Hey all, I just wanted to follow up. A big thanks goes to @stpeteshepherd for pinpointing my issue with the capacitors on the AC-CD Converter daughter board, as I did fix my intermittent hissing issue! More details below... With this kit being close to the cost of a mail-in repair ($130-$150 depending if you go with the kit or repair), you kind of need to weigh your own cost / benefit / abilities with a system this old. I reached out to @stpeteshepherd and decided to buy his 5.1 Ultra repair kit with a fan. My reasoning for going this route is: I have a beginner's ability to desolder / solder and have repaired this system before thanks to forum members like yourself sharing information. @stpeteshepherd has reengineered 3 components (BASH chips and AC-CD Converter Daughter board) to be cooler and longer lasting which is a godsend for a system this old with faulty parts. I also wanted a kit that had everything I needed to fix my current issue and future issues with this system without guessing, along with instructions. With that in mind, If I knew exactly what to replace, I could have bought some of the components that fixed my specific issue for less than $20, but I will inevitably have to replace/fix something in the future as these systems are prone to breaking due to heat issues. Something keep in mind that as time goes on: less and less people have these systems and Klipsch Promedia electrical enthusiast may not be selling / repairing these forever, so I figured buying now is an investment in the future of these 501 Ultras 😃. At first I sought out to do a full repair and replace everything in the kit, so I tackled the two 16v 100 uF and two 35v 100 uF capacitors at the upper right corner of the panel near the pair of small black heat sinks in the picture attached. Years ago I replaced the 35v 100 uF capacitors due to a bass hum, but I decided to replaced these with the new ones in the kit since they were and upgrade / a higher temp rating. Doing so, I accidentally pulled out a copper trace from the board because I didn't fully desolder. Stpteshepherd even warned me of this in the instructions 🤦🏼‍♂️. Re-attaching a trace is currently outside of my electrical wheelhouse, so I thought I ruined my system. I attempted to solder the capacitor back anyways on the top and bottom of the board and it seems to be working fine, but I'm not sure if this is a permanent fix or not. Due to this FUBAR, I decided to focus on what I believed my main problem was: The AC-DC converter board with the three 22uf 50v capacitors, 2N5551 transistor, and Zener diode on the AC-DC converter board (picture attached). I wanted to focus on this area first as this was the only area where the bottom of the board was charred. After replacing these 5 components and starting the system up again, it stopped buzzing and hissing. Once again, silence! Huzza! Pro tips: When removing the AC-DC board, use needle nosed pliers to grab the plastic mounts under the board and unscrew the screws holding those in place on the outside of the panel. I tried to press the plastic prongs in, but the plastic is so old the prongs broke off 😑. All in all, if you are having this problem and stumble upon this forum post, doing this repair is pretty easy and even a beginner with a solder sucker and a soldering iron can pull this off. @stpeteshepherd also gave instructions in the kit to replace many more commonly failed components and an internal fan kit to keep everything cool. Since my previous repairs are currently holding up (for now...), I didn't attempt to replace anything else in fear of causing more damage than good. I'm sure something will fail down the road, but I have the parts and instructions to tackle them when they come at me 😃. It's crazy to think about keeping these nearly 20 year old speakers going, but they still sound great and are fairly simple to repair. I hope this helps someone in the future!

Hey again all, I pulled apart the amp again and tried taking a closer look at the AC/DC converter and noticed some components that look a bit toasty. https://imgur.com/a/BUo3bmG I tried resoldering everything that looked like it might have come desoldered, but I don't really see much of an improvement in static. Does anyone know which bits of circuitry I should replace here? And if so, is there an easy way to identify what I need to purchase?

Hey again all, I pulled apart the amp again and tried taking a closer look at the AC/DC converter and noticed some components that look a bit toasty. https://imgur.com/a/BUo3bmG I tried resoldering everything that looked like it might have come desoldered, but I don't really see much of an improvement in static. Does anyone know which bits of circuitry I should replace here? And if so, is there an easy way to identify what I need to purchase?

Hey again all, I pulled apart the amp again and tried taking a closer look at the AC/DC converter and noticed some components that look a bit toasty. https://imgur.com/a/BUo3bmG I tried resoldering everything that looked like it might have come desoldered, but I don't really see much of an improvement in static. Does anyone know which bits of circuitry I should replace here? And if so, is there an easy way to identify what I need to purchase?

Hey there from the future! I have this same issue it seems. Did you (or anyone else) ever figure out a solution for it?

It is old and I've had to replace a both BASH chips and some resistors in the past, but they worked flawlessly until recently! I opened it up and took a look around, nothing appeared burnt or out of place. But I do hear a very similar high pitched static noise coming from the daughterboard that holds the BASH chips. I resoldered the BASH chip solder joints just in case, didn't seem to do anything. I'm assuming the culprit is somewhere in daughterboard, but I have no idea how to go about figuring out what needs to be replaced since everything is very tight and hard to get to. I know this seems like a "well duh dude" moment, but I do have an electric space heater in the same room I use occasionally and sometimes when I turn the heater on or off, the static over the speaker either turns on, off, or gets worse. This might point to an interference issue, but if the static can happen even if the heater is unplugged or off. I've had the heater for several years and it didn't trigger the static until very recently. With that in mind, I'm just assuming a component (cap or resistor) that is failing and can't take the power fluctuations the heater is causing. As for the DeoxIT, isn't this a solution for the volume knob? I don't seem to have static if I increase / decrease the volume. Or is there another way to use it?

Hey there from the future! I have this same issue with my 5.1 Ultra set where static comes from all speakers and changing the volume doesn't change the static. Did anyone solve this issue? I don't mind soldering resistors if need be. Thanks!

Hey there, I'm from the future! I have a 5.1 Ultra set, and I'm just now getting the hissing as described here. I agree with cpharrboy, I don't mind replacing whatever the the culprit is, but it would be helpful to narrow down the problem. Has anyone figured out a solution to this?

Hey there! I know this is an 11 year old post, but my 5.1 Ultras have developed this same issue, except the static does NOT increase or decrease if I change the volume. I've had this set since the early 2000's but previously, I have changed the BASH chip (twice over time!) and changed out the capacitors about 8 years ago. Not sure what to target here with this specific problem.

I seem to have this same issue but with 5.1 Ultra set. Did you even solve this issue? If not, I'll update if I find a fix for mine!

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!

Hey guys, I haven't touched my PC in a while (weeks-months) and came back to discover a annoying low-volume hum coming from my subwoofer. Also, when I switch to headphone mode, I hear a low volume hiss and hum that wasn't there before. I've completely removed the system from my PC, plugged the power into a lone wall plug, so I don't believe it's interference. I haven't visually checked the amp yet, I just wanted to get an idea from you guys first to see if anyone ran into this issue. On a side note, I replaced the BASH chip a few years back. Any leads? Thanks in advance!