Aboutcleggsan Expertise Consumer Electronics of all kinds. Audio, esoteric audio systems and components, video, tv. Digital equipment for consumer use. Ham radio and automotive electronics. Note: I give advice on tv repair based on general consumer electronics engineering experience but I am not engaged in actual repair of sets. MAKE SURE YOU GIVE THE MAKE AND MODEL NUMBER AND AGE OF THE SET.
Experience Electrical Engineering; recording, broadcasting, design, international standards, tv and radio theory and practice.
Organizations FELLOW of AES (Audio Engineering Society)
Senior Life Member of IEEE (Institute of Electronic and Electrical Engineers)
International Consulting Organization
Publications IEEE Spectrum
Various Consumer Electronic publications
Education/Credentials BSEE
MSCS
MBA
Awards and Honors Famous Engineer for Digital Audio
Question Hi just got this receivers off eBay, it is pretty good but one thing. The right channel does not produce sound at the proper level. its like it is muffled or something I have to turn the balance all the way over to the right channel to hear it, and turn the volume up about half way. I know the speakers are good, and they are hooked up properly. They are Polk RT-1000P's so they can handle what ever I hook them up too. Please help fix this problem as I can not afford to get another receiver new or I just would have got a new 7.1. Any advice or suggestions will help or a ruff estimate of what a repair would cost if I have to take it in. Also I did open it up and check all wire connections and they seem to all be in place and snug. Didn't touch anything else but the channel capacitors just checked for looseness in them was all haven't taken actual main board out not really advanced enough for all that my self, but my uncle is so if I can find out the problem he might be able to fix it. Thanks again.
Answer The first thing you must do is determine if the problem is internal or external.
EXTERNAL TEST: Disonnect both speakers. Connect the speaker on the good channel to the bad channel. Listen. Verify that the good speaker sounds poorly on the bad channel, thus proving the problem is internal to the amplifier.
INTERNAL TEST: Using the bad channel only (disconnect the speaker on the good channel) turn the volume down to minimum. Then with music signal playing, advance the volume control up very slowly just to the point of where you can begin to hear the music from the speakers. Listen a very low level, then advance it further and further. If the music is very distorted and then gets less distorted as you advance the volume level, then you have an off bias on the output stage of that amp and it will require replacement of the bias resistor in the emitter circuit, for example. If the distortion or muffled sound, as you call it, remains constant at all levels of the audio, then you probably have an IC issue or a predriver failure. Especially, if you can get full volume, only it is muffled and down in level, then this would be the case.
If you find one of the Polk speaker sounding poorly you may need to send it back to Polk for repairs.
I don't advise buying products of this kind over eBay for the simple reason that a large percentage of them are defective in some way and the owners use eBay because some one buying it in person or if it were traded in to the retail store, the defect would be easily uncovered.
For audio electronics, the rule should be never to buy it unless you can personally listen test it and make sure it is working to your total satisfaction before plunking down the money! Harsh rule, but the only safe way in todays technical world.
