Hissing with Promedia 5.1

[mbmiller]

For the last month or so my speakers have been making a hissing sound that varies in intensity, and will sometimes stop all together. Its gotten to the point where I swear I have nightmares about the hissing sound. The speakers also make a variety of sounds when turning on. The sounds have been getting worse recently and I really need some information about my options for this, I don't have the hissing sound when I plug a headset into the control pod jack, so I'm guessing its something to do with the Amp again. It broke down the first year I got it and it was replaced with this unit which is getting around 5 years old or more. Any suggestions, and thank you for the help.

03-D-0197598-C

[timmydos]

Just thought I'd add to this comment - I have the exact same thing happening and it started around a month ago on my Promedia set from around 2005. Intermittent, but frequent, hissing at various levels.

I have unplugged all speaker connections between PC and Sub but it only goes away if I cut power at the Control box or power outlet.I tried re-routing the power cable to reduce interference, with no effect. I tried all manner of software settings in Windows.

I'm baffled by it and would also love to get in on any expert suggestions.These speakers are great, so I hope it isn't an end-of-life scenario.

Tim

[mbmiller]

Is there any additional information on this? Is it my amp, or something else? And I live in edmonton alberta, is there an authorized dealer here? It was suggest on a few posts that Klipsch might be able to replace the unit or has that been discontinued. I've been looking for options to replace the sub / reciever but most of them are out of my range and I can't find anything that I could swap out yet that could replace both the sub and reciever unit.

[stpete cooling]

I've seen hissing happen from capacitors drying on the power supply, or one of the BASH chips failing, or arcing on the power supply's daughterboard due to charring from longterm operation at high temperatures. Humidity will make a difference on the arcing (making it intermittent with the humidity in the room). Those are the most common I've found. There could be a few other causes. Of those causes mentioned above, I've generally been able to repair them, and get rid of the drying and charring problems. There really are few options that give the nice sound and power of the ProMedia 5.1. If I can be of further help, let me know.

[mbmiller]

What exactly are you offering? Do you have a website?

[stpete cooling]

Sorry I did not check back sooner, and was not clearer.

If someone had started troubleshooting further and had new questions as they went, I was offering to help from my experience. I have repaired panels for others, but I am not sure Klipsch or forum readers want either a private person (e.g., me) or a business to be seen as soliciting. If you wish to contact me via email or private message, that may be the best method for repair options outside the forum.

[cwaters]

I'm having the exact same problem. The hissing noise began about a month ago. It varies in intensity, lasts for a few minutes, and then disappears.

Adjusting the volume using the control pad wheel has no effect upon the hiss. Switching the control pad over to headphone mode temporarily eliminates the hiss but it returns when the control pad is switched back to non-headphone mode.

After the hiss disappears, it might not re-occur for hours or even days...or it might occur again within a few minutes.

The system is about six years old. Klipsch repaired the amp about four-and-a-half years ago. Klipsch's customer service department told me today that it sounds like the amp needs to be repaired.

I'm unsure whether its worth fixing (again) or whether I should simply buy a replacement system--Klipsch or perhaps Logitech.

Appreciate any comments.

[airjer]

I have the same issue going on... it's extremely annoying, I'd like to get these fixed so if anyone has any suggestions or connections let me know please!

[cpharrboy]

I am also having the same issue. The hissing started when I turned the unit on and then it would fade away. Now the hissing is intermittent to constant. The volume of the hissing is constant and does not change with the volume knob. I'm quite good with electronics but do not like having to check each and every single part as it is far too tedious and my patience is not what it used to be. If anyone happens to know what parts cause this I can replace them on my own.

I would like to add that I have had this unit for 8 years now with no issue so they have served me well. There is nothing else available that compares and I just don't want to have to settle for less. I guess Klipsch just wasn't making enough sales on these units to continue producing them....I dunno.

[K.C. Cool]

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?

 

[K.C. Cool]

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?

[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!

[oibctl]

Hey KC,

Thanks so much for taking the time to document this!  I am in the same boat, that is the hissing coming from the speakers.  I too have a bit of soldering experience and would like to give this a shot before abandoning it for a new set up.  I found the location of the capacitors thanks to your pics and have a few questions:

1.  Can you give me the values of these?  There appears to be two of two different kinds

2.  There appears to be 3 screws attaching the board to the assembly, one of which is not accesable, how do you recommend disassembly to change out those 4 capacitors. 

 

Any other advice would be appreciated, thanks!

Chris