Hello all.
Don't want to create too lengthy a post so I'll keep it brief.
An opportunity arose in me acquiring an A5.5 amp for what seemed a bargain price and the amp was shown to me working so I jumped at the chance. On getting the amp back home, I noticed from the screws that hold the lid on, that someone had been inside so, thought I'd have a look myself just to ensure everything was fine. Inside, everything looks fine apart from that one of the fuses were blown. The thing is, the amp still powers up fine and produces good sound from both channels. I'll try to add a photo or two shortly but I'd appreciate any input that can help me. Thank you.
Don't want to create too lengthy a post so I'll keep it brief.
An opportunity arose in me acquiring an A5.5 amp for what seemed a bargain price and the amp was shown to me working so I jumped at the chance. On getting the amp back home, I noticed from the screws that hold the lid on, that someone had been inside so, thought I'd have a look myself just to ensure everything was fine. Inside, everything looks fine apart from that one of the fuses were blown. The thing is, the amp still powers up fine and produces good sound from both channels. I'll try to add a photo or two shortly but I'd appreciate any input that can help me. Thank you.
A fuse blown means one rail in one channel is missing. Usually that leads to increased offset which should trip the dc protection There is no way an absent rail won't cause gross distortion too. Are you certain the fuse is really blown?
Yes, the fuse is certainly blown. When I lifted the lid and saw the blown fuse, I thought it may have happened during the last power off/on or something because I was certain it was working when I last heard it not long before. So, I replaced the fuse and upon power up it blew again but carried on the power up process, engaging the relay and outputting sound. I was puzzled by this but carried on listening for just a few minuted before powering down and coming here with my findings. Although I didn't crank the volume much, it was at medium volume and I couldn't hear any distortion at all. I'm wondering if any dodgy repair has been done? Maybe some bypass or something. I think I strip down and investigation is needed. Any further thoughts would be much appreciated.
Yes. I was thinking the same so, desoldered the rectifier and it is shorted between two pins. Will order a replacement. Is there a specific reason why it would have failed?
What is stange is that the bridge rectifier for the good channel is different to the bad one I'm replacing. I wonder if that side had failed in the past? The rectifier I'm replacing is a BR104 but the one in the good channel is KBPC604. Would it be better to replace with KBPC604 or stick to BR104?
I think the original part is BR104 and the other channel must have previously been replaced with KBPC604. Looking at the specs, although both are 400v, the BR104 is 10A and the KBPC604 is 6A as far as I can tell so, I would like to replace both to original spec of 10A. I'm struggling to find BR104, is there an alternative?