Hi all, My Panasonic SA-AK600 started displaying the dreaded F61 fault code recently and like most of you I starting looking on the internet for an explanation. I found that many had mentioned the power amplifier / power transformer so I started investigating that possibility first. I found two part numbers STK470-050A and STK470-090. My system has High wattage output and used the larger IC - STK470-090. This part has been replaced with part number C5BA00000105 but when the part arived it had the number STK470-090B stamped on it. I purchased this IC online from Best Buy - but CompUSA also had the same part - my guess from the same warehouse. Note here - this IC is soldered to the printed circuit board (PCB) so unless you are mechanically competent I would not recommend trying to repair this system. You will also need a soldering iron, very small diameter solder, and a solder remover in order to remove the old IC. Also the back of the IC is covered is dielectric grease for cooling and signal noise reduction. Also should note here that the part showed no sign of being broken so I took a chance that this was the problem. From what I have read there can be other things wrong with the system - so there is no guarantee changing this IC will fix your system. Turns out that this IC is the most common problem with panasonic stereo systems. Also, I was unable to find any technical description of what this IC does or what the outputs are so I was unable to verify just what it does or how to verify it was broken. I also thought heat was the culprit and thought maybe the fan was out. However, I found that the fan is on a thermal circuit and wont come on until the unit reaches a certain temp. My fan seamed to be working OK but those of you with noisy fans might need to look there first. The IC is soddered from the bottom side of the PCB so I had to disassemble the entire stereo to get the PCB out to perform the repair. Fortunately the design of how this system fits together was pretty slick and taking it apart was not too bad. Basically I removed the old IC - CAREFULLY (using very little solder) I soldered in the new IC - re-installed the PCB and reassembled the case. I double checked all the connections then powered on the system and the dreaded F61 was gone! Systems been working for a week now. Total cost 25$ for the IC which included shipping. I ordered from Best Buy and it took less then a week to arrive. I did have to buy a solder remover from Radio Shack and some small diameter solder for another $12 so I'm out $37.00 bucks. I hope this helps those of you with similar stereo systems. I've also seen DVD players with same code but I have not been able to determine if the problems are the same. The part number I used didn't cross reference any DVD systems. My guess however is there is a common link. I think heat is the biggest cause of these problems. These IC's cant take the heat and eventually fail and like one post said these IC's are the biggest heat sink in the system. Your mission - should you except it - is to repair your own F61 fault. Good luck and Go - for - It. What have to got to loose? Even if you fail - you will learn from the experience and folks - knowledge is power!

i have the same problem with an old technics hifi system: one second after powering on it shuts down with error F61. where's the problem? what's wrong?