eubassix Posted October 4, 2023 Share Posted October 4, 2023 (edited) no previous issues with this. Not used for a while but yesterday evening played (home) at low volume for about 20 minutes .... and then nothing. Not powering up. I’ve changed the kettle lead with no change. The fan wasn't on but can't recall if this is permanent or kicks-in when required (?) - but no apparent heat (or 'smell'). I checked the 2 internal (glass) fuses and both OK (... was hoping this might be the simple fix)............ Any thoughts / ideas ?...... Edited October 4, 2023 by eubassix details Quote Link to comment Share on other sites More sharing options...
BassBunny Posted October 4, 2023 Share Posted October 4, 2023 Could it be the main input fuse on the back of the amp? Housed just underneath the mains socket. Quote Link to comment Share on other sites More sharing options...
eubassix Posted October 4, 2023 Author Share Posted October 4, 2023 40 minutes ago, BassBunny said: Could it be the main input fuse on the back of the amp? Housed just underneath the mains socket. Thnks BB :- 1. 'Discovered' a “hidden” fuse in the power input which has clearly blown. Replaced it ............... 2.This does seem to be the problem. I’ve replaced the 250v fuse in the power input and this has blown again. Quote Link to comment Share on other sites More sharing options...
sandy_r Posted October 4, 2023 Share Posted October 4, 2023 3 hours ago, eubassix said: Thnks BB :- 1. 'Discovered' a “hidden” fuse in the power input which has clearly blown. Replaced it ............... 2.This does seem to be the problem. I’ve replaced the 250v fuse in the power input and this has blown again. did you replace the blown fuse with a 250V 3A Slo Blo fuse? Quote Link to comment Share on other sites More sharing options...
BassBunny Posted October 4, 2023 Share Posted October 4, 2023 6 hours ago, sandy_r said: did you replace the blown fuse with a 250V 3A Slo Blo fuse? Should be a 4A Slo Blo apparently, although I don't think it would make much difference using a 3A. Good shot of the rear of the amp in this F/S ad. Quote Link to comment Share on other sites More sharing options...
sandy_r Posted October 5, 2023 Share Posted October 5, 2023 (edited) 16 hours ago, sandy_r said: did you replace the blown fuse with a 250V 3A Slo Blo fuse? 9 hours ago, BassBunny said: Should be a 4A Slo Blo apparently... Not necessarily, it seems! ...but @eubassix can confirm that they've used the same rating&type of fuse shown on their amp rearplate Edited October 5, 2023 by sandy_r Quote Link to comment Share on other sites More sharing options...
eubassix Posted October 5, 2023 Author Share Posted October 5, 2023 ... thanks for the suggestions/help: ordered some new / corrct fuses. Hopefully this will sort the issue; but - worst case scenario - what might be the issue IF the fuse(s) continue to blow ? Quote Link to comment Share on other sites More sharing options...
BassBunny Posted October 5, 2023 Share Posted October 5, 2023 @sandy_r How strange. Same amp, different stickers. Wonder what the story is behind that? I don't think EA exist anymore so not possible to find out. @eubassix If it keeps blowing, I would suspect a power supply problem. A blown component or mains transformer problem. I don't know if the schematics are available but I would involve a decent amp tech. Quote Link to comment Share on other sites More sharing options...
sandy_r Posted October 5, 2023 Share Posted October 5, 2023 (edited) 20 minutes ago, eubassix said: ... thanks for the suggestions/help: ordered some new / corrct fuses. Hopefully this will sort the issue; but - worst case scenario - what might be the issue IF the fuse(s) continue to blow ? Unfortunately this is a 'how long is a piece of string' type question Blowing a 3 or 4 amp Slo Blo fuse (originally?) is a reasonably robust short-circuit (ie the fuse blew before, say, a sliver of solder evaporated) If you feel confident doing so, you could open the case and try and inspect the components and underside of circuit board and report back any signs of carbon, heat effects, bulging electrolytic caps, etc. This should give some idea of the failure mode and possibly influence decisions for professional repair/retirement of amp Otherwise just take it to a reputable repair tech and get an estimate Edited October 5, 2023 by sandy_r Quote Link to comment Share on other sites More sharing options...
sandy_r Posted October 5, 2023 Share Posted October 5, 2023 ...for completeness... if the amp powers on (and stays on as needed!), after you've replaced the main fuse with the plate-rated item, then it's likely that the amp is healthy - manufacturers use Slo Blo type fuses (of the required rating) to enable the amp to cope with 'Inrush Current' to the PSU. This is a one-off power surge which occurs when the power supply caps first start charging up to operating voltage and is fairly instantaneous, hence a relatively slow-acting fuse won't respond, whilst a permanent fault will endure and blow the fuse So why did the original fuse blow? - old/incorrect fuse finally expired; - actual/marginal fault condition developing (would need further checking) hth Quote Link to comment Share on other sites More sharing options...
eubassix Posted October 5, 2023 Author Share Posted October 5, 2023 Thanks sandy_r - the responses from yourself and BassBunny are really helpful / informative. I'll update with developments asap. 1 Quote Link to comment Share on other sites More sharing options...
Skinner Posted January 4 Share Posted January 4 I had an iamp 800 about 7 years ago, it suffered a massive drop in output/volume, took it for repair, the guy said it had been worked on in the past, sorted it, but I wasn't confident that it would be reliable long term. Quote Link to comment Share on other sites More sharing options...
pete.young Posted January 4 Share Posted January 4 Missed this thread originally. My one has a 3A sticker and appears to be older than the one in the for-sale thread so I guess they uprated the fuse for later designs. The fan should come on as soon as the amp powers up. Quote Link to comment Share on other sites More sharing options...
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