32blownhemi Posted October 20, 2017 Share Posted October 20, 2017 Any ideas on what could be wrong? It's getting power cuz the little red power light is on. It just does nothing when I flip the on/off switch. It hasn't got that many hours on it either. I have 2 & not sure which McIntosh dealer this one came from. One was brand new in the box. The other was a show room demo which they said had very few hours on it... Got one last April the other in July or so. Any fuses? Or? Is this the right place to post this? Thank You! Bill Quote Link to comment Share on other sites More sharing options...
wvu80 Posted October 20, 2017 Share Posted October 20, 2017 I am not the Mac guy, so I'll bow out immediately and let the smart guys diagnose this after a small suggestion; can you take the cover off and do a visual inspection to see if anything is obviously wrong? Is there any smell of burned electronics? Sorry I couldn't be of more help. Quote Link to comment Share on other sites More sharing options...
derrickdj1 Posted October 20, 2017 Share Posted October 20, 2017 Are all the tubes lit up? Are you using a preamp? Have you tried a second source? This problems needs a lot more info. Quote Link to comment Share on other sites More sharing options...
32blownhemi Posted October 20, 2017 Author Share Posted October 20, 2017 Thank You! No smell at all. It looks pretty involved to take the cover off. I'll go youtube it & see if it shows how. When it's plugged in the little red light that's right beside the on/off switch is on so it's getting power. I do have a pre-amp but none of the tubes are on. Nothing shows on except the little red light that shows it's plugged in. The other day when I went to turn the amp on it wouldn't go on. I checked the power cord & it was pulled out so I put it back in. I can't remember but I don't think the power switch was on when I plugged it back in but it might have been. Could this have done something? Although I've used it several times since that happened.... Thanks, Bill Quote Link to comment Share on other sites More sharing options...
pzannucci Posted October 20, 2017 Share Posted October 20, 2017 There may be an internal circuit that shuts down if there is a tube problem. I would recommend looking on line for schematics (after you open it up and see if there are any internal fuses), and see what may be common on the power supply side between the tubes. Not much help either, sorry. Quote Link to comment Share on other sites More sharing options...
Schu Posted October 20, 2017 Share Posted October 20, 2017 Have you checked those 150$ fuses Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted October 20, 2017 Share Posted October 20, 2017 Since the amp is not that old, call either Mac dealer and explain the situation. They can lead you through the preliminary trouble shooting. if there were any sort of warranties, I would not dismantle anything or even touch the screws heads. 1 Quote Link to comment Share on other sites More sharing options...
USNRET Posted October 20, 2017 Share Posted October 20, 2017 Are you using a trigger to turn on? If so remove it and try the manual switch. Is auto off engaged? Quote Link to comment Share on other sites More sharing options...
Chris A Posted October 20, 2017 Share Posted October 20, 2017 Time to test the tubes--KT88s and the 12at7s. Or you can trade the Mac amps in and get SS which have much longer MTTF, i.e., no periodic maintenance required. Tubes have to be replaced every few thousand hours (or perhaps less), and they constantly change their operating performance over their useful lives. I believe that's an unnecessary complication those that aren't into diddling. With your set up, I think you'll be hard pressed to hear any differences between the tubes and their SS brothers (McIntosh, First Watt, etc.). The effect of tubes usually only becomes audible when the input impedance of the loudspeakers drops below about 8-10 ohms. In any case, those differences can mostly be EQed flat again using the Xilica. Chris Quote Link to comment Share on other sites More sharing options...
jimjimbo Posted October 20, 2017 Share Posted October 20, 2017 49 minutes ago, Chris A said: Or you can trade the Mac amps in and get SS Here we go again. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted October 20, 2017 Share Posted October 20, 2017 11 hours ago, 32blownhemi said: I have 2 & not sure which McIntosh dealer this one came from. One was brand new in the box. The other was a show room demo which they said had very few hours on it.. Don't you have serial number and a matching bill of sale that will show which dealer...? 1 Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted October 20, 2017 Share Posted October 20, 2017 3 hours ago, PrestonTom said: Since the amp is not that old, call either Mac dealer and explain the situation. They can lead you through the preliminary trouble shooting. if there were any sort of warranties, I would not dismantle anything or even touch the screws heads. This^^^^^ 57 minutes ago, mikebse2a3 said: Don't you have serial number and a matching bill of sale that will show which dealer...? And This^^^^^^^^ 1 Quote Link to comment Share on other sites More sharing options...
USNRET Posted October 20, 2017 Share Posted October 20, 2017 if these are MK VI version it is supposed to identify faulty tube by color of LEDs around the tube (if you have the lights commanded on) Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted October 20, 2017 Share Posted October 20, 2017 Have you done and verified everything is correct for your setup On/Off sequence..? INPUT SWITCH in correct position..? Is Sentry Monitor activated. ...? Quote Link to comment Share on other sites More sharing options...
32blownhemi Posted October 21, 2017 Author Share Posted October 21, 2017 Thank You for all the replies! Ok, found the receipt & it's the amp I bought new not the store demo one. I called em & they had me run through a procedure. Turn on the auto off switch, unplug the amp, wait 2 minutes, plug it back in, turn the auto off switch off & then turn the unit on. But it still didn't go on. I then checked the only user serviceable fuse & it was good. The guy said it probably wasn't the fuse but I checked it anyway. There's a 90 warrantee on Tubes & 3 years on the rest & he said to bring it in. Said that if only one tube is bad it might not turn on but I thought the tubes lit up a different color if they were bad (it's a Mc275 MK VI). The salesperson did say he didn't know much about tube problems but said he was surprised because they were relatively trouble free. Guess he lied, hug? Lol... I should probably consider going to SS. I don't want to be messing with stuff all the time... And I plugged the amp that doesn't work into the same electrical socket that the good amp was plugged into. And the settings on the bad amp are set the same as the good amp... I bought the amp in May so the warrantee on the tubes is up but he said not to worry about it. That he thought Macintosh would cover any bad tubes.... Thanks again! Bill 1 Quote Link to comment Share on other sites More sharing options...
pzannucci Posted October 21, 2017 Share Posted October 21, 2017 4 hours ago, 32blownhemi said: The salesperson did say he didn't know much about tube problems but said he was surprised because they were relatively trouble free. Guess he lied, hug? Lol... I should probably consider going to SS. I don't want to be messing with stuff all the time... That he thought Macintosh would cover any bad tubes.... Thanks again! Bill Relative is relative sadly. Hope it is something like a bad tube but if they are all on and glowing the same, sounds a little less likely. Quote Link to comment Share on other sites More sharing options...
Moderators Travis In Austin Posted October 21, 2017 Moderators Share Posted October 21, 2017 Post in this one Quote Link to comment Share on other sites More sharing options...
Deang Posted October 21, 2017 Share Posted October 21, 2017 You should work with McIntosh at figuring out the issue - and stay with tubes - which sound subjectively better. Quote Link to comment Share on other sites More sharing options...
32blownhemi Posted October 22, 2017 Author Share Posted October 22, 2017 19 hours ago, pzannucci said: Relative is relative sadly. Hope it is something like a bad tube but if they are all on and glowing the same, sounds a little less likely. Nothing is on except the light telling me it's plugged in. ... Quote Link to comment Share on other sites More sharing options...
32blownhemi Posted October 30, 2017 Author Share Posted October 30, 2017 So took my amp into the McIntosh dealer last Monday, he said the repair guy would pick it up on Tuesday & he'd call me either Tuesday or Wednesday to let me know what was going on. Well, Saturday rolled around & I still hadn't heard from him so I called. He knew nothing, said he'd call the guy & call me back. Yeah, you guessed it. He didn't call back... Hope this doesn't turn into a disaster... Quote Link to comment Share on other sites More sharing options...
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