mccaffrp
mccaffrp
Hello all,
I did something careless today. I've had a beautiful, brand-new-like Kenwood KA-5500 for about 10 years now and it does not get much use. Well, today I was checking bias and offset on all of my Kenwood amps and I checked the right side of this amp, it was a bit low, set it, fine. Moved on to the other channel and I connected my DVM to pin 23, fine. Then I mistakenly connected the other lead to pin 26 (should have been pin 25!) and pop! The 5A fuse blew on the power supply board. OK, I replaced it and moved my meter to the right pin and turned it back on, the protection relay did not click.The lamp lit up but then I saw smoke near the area on the main power board I was working on but could not tell which component it was. I shut the unit off. Since the relay did not click, as exepcted I had no reading on the meter. Now I have to reiterate that this unit was like brand new. I mean this thing was not even dusty inside! DC offset was at 28 ma with all original caps and I was just checking bias and offset - getting it ready to use while I recap my KA-3500. I feel like an idiot. A 57 year old who needs better glasses type of idiot. Can someone help walk me through the basic checks on the power supply and the main power board so I can find the bad components please? The manual has some basic steps but I am not exactly sure where to check the center voltage on the power amp. I looked and saw Mr. Echowars is MIA, so I hope someone else knows this amp well enough to help. I have the schematic, however I am a bit gun shy and would prefer some basic guidance from someone who knows this amp well. Thanks a million to everyone in the community!
I did something careless today. I've had a beautiful, brand-new-like Kenwood KA-5500 for about 10 years now and it does not get much use. Well, today I was checking bias and offset on all of my Kenwood amps and I checked the right side of this amp, it was a bit low, set it, fine. Moved on to the other channel and I connected my DVM to pin 23, fine. Then I mistakenly connected the other lead to pin 26 (should have been pin 25!) and pop! The 5A fuse blew on the power supply board. OK, I replaced it and moved my meter to the right pin and turned it back on, the protection relay did not click.The lamp lit up but then I saw smoke near the area on the main power board I was working on but could not tell which component it was. I shut the unit off. Since the relay did not click, as exepcted I had no reading on the meter. Now I have to reiterate that this unit was like brand new. I mean this thing was not even dusty inside! DC offset was at 28 ma with all original caps and I was just checking bias and offset - getting it ready to use while I recap my KA-3500. I feel like an idiot. A 57 year old who needs better glasses type of idiot. Can someone help walk me through the basic checks on the power supply and the main power board so I can find the bad components please? The manual has some basic steps but I am not exactly sure where to check the center voltage on the power amp. I looked and saw Mr. Echowars is MIA, so I hope someone else knows this amp well enough to help. I have the schematic, however I am a bit gun shy and would prefer some basic guidance from someone who knows this amp well. Thanks a million to everyone in the community!