larryklipsch

You, and others, may request it from mailto:support@klipsch.com Good luck and let us know how it goes.

Ignacio, That's great news. Not many people can fix their own amplifier. I was out of town and just got back to find my capacitors in the mail. I installed them this morning in the failed amp and wow, it works great. I don't remember the sub sounding this good. I will be replacing the capacitors in the other one too. It's too bad a great speaker company like Klipsch uses an amp with crappy components. The workmanship was also poor. There was lots of rosin all over the board. Larry

Ignacio, Thanks for sharing this info. I believe you may have interpreted the manual incorrectly. Let me know if this is correct: 2 Check all filter capacitors. C6, C8, C9, C10, & C11 - from the manual C6 and C8 refer to the filter capacitors on the power amp. C8, C9, C10, and C11 refer to the filter capacitors on the preamp. Also, I found high-quality capactors on Ebay and they shipped very quickly. I had to buy them from different vendors though. You are correct about the voltage. Higher volatage is ok if it fits. Keep us up to date on how it goes. Larry

I wrote an assertive email to customer service and here's the response: Larry,I was responding to option B from your request. Since this unit has been out of production for quite a long while, I can include the service manual for this which is attached to this email. We however, can not provide tech support for the electronic components of the amp assembly. We do not scan the forums as we receive about 200-300 emails daily as well as live phone support M-Friday 8am -5:30 pm EST along with a new Live Chat option on our website as well. Hope this may help you. The service manual contains schematics and shows power supplies on both boards. It also lists the capacitors to replace to fix hum. I am pleased with this result and will post again after I replace the other capacitors

Thanks for the info. I see what you're saying. People don't fix things any more and there isn't much traffic here. I can't believe a reputable company like Klipsch doesn't scan this forum and that they wouldn't be forthcoming in providing schematics! This does bend me out of shape. I keep equipment for a long time so I buy quality items. All other manufacturers have downloadable everything readily available. It seems that I could buy an aftermarket plate amp and adapt it. I'd be willing to do the work but would much rather keep everything looking original. Thanks for your offer. I'd like to look at the KSP-400 schematic but still think that Klipsch should make schematics readily available. What's their problem?

OK, as I mentioned earlier I replaced the two 470uF 63V capacitors with some high-quality ones. They had definately been leaking. This didn't stop the hum. Then I noticed some xformer wires going to the other (control?) board. I detatched that board and found it had lots of electrolytics on it. There was a group of 3 of them together that I thought might be of interest. They don't look bad though. They are 2 470uF 25V and 1 100uf 50V. Does any one know what these caps are about? It would sure be nice if I could get a SCHEMATIC!

Thanks, much more helpful though I've read this one. It comes closest to solving the problem. Schematics?????

This is not a welcoming and friendly reply for a fellow audiophile in need. Also, it helps to look at the questions-all of them. I am requesting a source for schematics which would be most helpful in troubleshooting this problem. I would like to hear from people who have experienced and fixed this problem or can point me to some useful information. Others need not apply. I have searched this forum quite extensively. I have read many posts here about hum on the KSP300 and other units both on this forum and other places on the Internet. Posting here is, as it should be, a last resort. If you can point me to something I may have missed, thanks for being helpful.

I just posted to the form. I am having the exact problem you describe and replaced the capacitors to no avail. It still hums. Did you find a solution?

My KSP 300 developed a 60Hz hum. The speakers still put out sound. I diagnosed it to the subwoofer by disconnecting everything but power. The power cord is isolated from ground. I plugged it into the same outlet as the other speaker and it still hums. I sent an email to customer service and they ignored some of my questions and told me where to send it for repair at a flat rate of $240.00 and that they couldn't provide any parts. There are some decent plate amps on the market to replace these with for around $100.00 so $240.00 is out of the question. I would like to keep these original if I can. I decided to take a gamble and replace the 4700uf/63V capacitors thinking they were the likely problem. The caps had indeed leaked quite a bit. Replacing them with high quality caps didn't solve the hum problem. I notice that there's another set of wires from the xformer to the other board. I haven't looked yet but it too must have a power supply complete with decoupling caps. Before I go further it would be nice to have a set of schematics and info from others who have fixed this problem. Has anyone out there fixed the hum problem? How? Has anyone replaced the amps with a different plate amp? Which? Where can I get a schematic?