Coytee Posted January 8, 2005 Share Posted January 8, 2005 Getting ready to work around house, prepared to turn some background music on... Jolida 502-B, plugged into a power strip along with cd player. Reached down, turned strip on per usual, as Jolida was warming up, I heard the typical "hum" that it briefly gives. All the sudden, the hum changed somehow, was so short, I didn't really have time to digest it. I then noticed the far left power tube (6550) had for a short duration, a bright flair inside of it. The flair went out and the amp died. Not even the power light is on (??) I presumed I blew a fuse, didn't see a fuse anywhere. I got the manual out and it CLEARLY shows a fuse right next to where the power cord goes into the rear right corner. Guess what? my unit does NOT have a fuse in that location. The manual does NOT show an extra ground connector. guess what, my amp HAS that ground connector. Sooooooooooooooo, no power light, I pulled each tube (ALL of them) out & looked for a burn spot, rattled gently for broken filiment (like light bulb...does that work by the way?) Nothing, dead, nada. Can I somehow test a tube with multi meter? Interestingly enough, just other evening I was looking at the far RIGHT tube and noticed what I thought to be a red glowing dot on the very top of the inside structure. It seemed to have a higher glow there than the other three. how are these things setup? My guess is/was the two left tubes are left channel, the two right tubes are right. Or, is it outside tubes 1 channel and inside tubes, other channel? Anyways, given today is saturday, I realize I'm toast until Monday. I'll call the vendor up, including Jolida & see what they all have to say. Can a blown tube kill the POWER light, or is something more ominous going on here? Quote Link to comment Share on other sites More sharing options...
Colin Posted January 8, 2005 Share Posted January 8, 2005 power strip or surge protector? sounds like power supply took a hit... Quote Link to comment Share on other sites More sharing options...
rtaylor Posted January 8, 2005 Share Posted January 8, 2005 Not being familiar with your amp all I can advise to do is unplug it and open it up to find the fuse that blew. Make sure you only put one hand in there at a time and don't be touchin' anything else besides the fuse,IMPORTANT. That said you'd probably be best off finding a technician to look it over. Sometimes it seems to me that one or more of my tubes glows a little more than the other but if your tube did flash either it or a resistor or capacitor has given up the ghost. Do you know of anyone in your area you can trust to look at it? If not maybe one of the more tech guys here can help you,,Sorry for your troubles,Randy Quote Link to comment Share on other sites More sharing options...
Coytee Posted January 8, 2005 Author Share Posted January 8, 2005 heck (cleaned up that word ) for something about 8 weeks old, I'll let the manufacturer take care of it. I'll be happy to be their hands and do what they tell me to do, probably via fax so as to not let them later say I did it on my own... that said, I realize it will probably have to be sent back to them. I'm usually hesitant on opening anything up while under warranty. After warranty is over, watch out though Hate to hear speculation on the power supply (oh, the power strip is fine, as per evidence of cd still working). I'd much rather it be just a defective tube. Sheesh... bring back my 25 year old Yamaha and sibilance... Quote Link to comment Share on other sites More sharing options...
rtaylor Posted January 8, 2005 Share Posted January 8, 2005 AAACK,,no not the SS again. LOL Yes, the manufacturer is the one to talk to. Sorry. You did check the power to the amp? So the problem is not your power strips. Quote Link to comment Share on other sites More sharing options...
Colin Posted January 8, 2005 Share Posted January 8, 2005 failure with tube amps is rare, more like things go bad slowly, sorry... Quote Link to comment Share on other sites More sharing options...
oscarsear Posted January 8, 2005 Share Posted January 8, 2005 You'll need to get a return goods authorization # direct from Jolida. I returned a 502B shortly after purchase due to excess noise. Good Luck. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted January 8, 2005 Share Posted January 8, 2005 ---------------- On 1/8/2005 4:30:49 PM Colin wrote: failure with tube amps is rare, more like things go bad slowly, sorry... ---------------- Maybe but so are white Christmas's in South Texas, they happen! Not a fun thing to happen to your new amp Coyotee. Sounds like you had a loose or warped grid in that tube. It shorted and blew the fuse. Did you mark the tube that arced so that you never try it again? Did it come from a local dealer? I'd be back there today! At least to get some new tubes from another amp and a new fuse. Somewhere there is a fuse. If not they would never be able to get UL or Canadian approval. Rick Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted January 8, 2005 Share Posted January 8, 2005 Richard said: I presumed I blew a fuse, didn't see a fuse anywhere. I got the manual out and it CLEARLY shows a fuse right next to where the power cord goes into the rear right corner. Guess what? my unit does NOT have a fuse in that location. The manual does NOT show an extra ground connector. guess what, my amp HAS that ground connector. All the sudden, the hum changed somehow, was so short, I didn't really have time to digest it. I then noticed the far left power tube (6550) had for a short duration, a bright flair inside of it. Interestingly enough, just other evening I was looking at the far RIGHT tube and noticed what I thought to be a red glowing dot on the very top of the inside structure. It seemed to have a higher glow there than the other three. ------------------------------------------------ Richard I'm not sure in your case but some equipment has the main power fuse holder as an integral part of the AC socket on the back of the unit that you plug the AC cord into so you might want to look real close at it. Like others have said the tube with the bright flair probably has a short in it which might not show up unless under a load but anytime you see a "arching flash" in a tube it should be replaced before it has time to damage other circuity. If your tubes getter(this is how they burn off any residule gas when the tube was made and leaves a dark or silvery area on the glass envelope) is located toward the top then looking through it toward the filament structure of the tube you might notice a difference in brightness due to the variation in the getter deposits left on the different tubes and isn't a sign of any problems with the tube. But if you see any Arching/Flashing light in a tube then it should immediatly be replaced as soon as possible. mike Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted January 8, 2005 Share Posted January 8, 2005 your tube socket probably arced over ... check them, and the screem resistors, before you try to power up again ... and buy some new tubes on a regular basis don't forget to check/ set the bias .... Quote Link to comment Share on other sites More sharing options...
Coytee Posted January 9, 2005 Author Share Posted January 9, 2005 Update: (call me bold or stupid) First off, 3d, thanks for the comment about fuse. I'd concluded it was on the INSIDE of the case, and because of warranty stuff, wasn't going to open it. You are right, it was integral with the plug, I'd never seen it had it not been suggested to look for it there. ok, the fuse was TOAST!!! I mean entirely blackened glass tube. Fortunately, this had a spare!! Popped the spare in and had the big debate... Do I, or don't I? Well, I DID and it "seems" to be working just fine. So, can a blowing fuse, cause a tube to glow a bit during that process or by definitino, by seeing that glow in tube, do I FOR SURE, have a problem? Anyways, I turned it off and learned something else. I had the volume up a bit (to very quiet level) and turned it off... well, unlike my SS stuff, this didn't turn "off" at the flick of the switch, it sort of coasted off and faded away as it died. Not sure if tubes are supposed to do that or not, but that's what happened. Any thoughts? Quote Link to comment Share on other sites More sharing options...
fairchild260 Posted January 9, 2005 Share Posted January 9, 2005 I had the volume up a bit (to very quiet level) and turned it off... well, unlike my SS stuff, this didn't turn "off" at the flick of the switch, it sort of coasted off and faded away as it died. Not sure if tubes are supposed to do that or not, but that's what happened. Any thoughts? this is normal at least for all my tube amps its just the filter caps bleeding off (or discharging) chris Quote Link to comment Share on other sites More sharing options...
lynnm Posted January 9, 2005 Share Posted January 9, 2005 Changing the fuse did not fix your problem and you still need to contact Jolida. I do not recommend powering up that amp until you have them repair it. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted January 9, 2005 Share Posted January 9, 2005 Coytee said: So, can a blowing fuse, cause a tube to glow a bit during that process or by definitino, by seeing that glow in tube, do I FOR SURE, have a problem? Anyways, I turned it off and learned something else. I had the volume up a bit (to very quiet level) and turned it off... well, unlike my SS stuff, this didn't turn "off" at the flick of the switch, it sort of coasted off and faded away as it died. Not sure if tubes are supposed to do that or not, but that's what happened. --------------------------------- Coytee my guess is if you saw a flash in one of the 6550 output tubes then you probably have an intermittent short in that tube which will eventually show up again.Since your fuse blew so hard(blackened glass as opposed to just a slightly open fuse element indicates to me a heavey overcurrent draw(short)not just a failure of the fuse.I personnely would want to replace that tube or that pair if they are matched. Also the sound slowly dying away is just the power supply discharging its energy storage and is completely normal. mike Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted January 9, 2005 Share Posted January 9, 2005 it sure sounds like a tube broke down under load .. the black fuse shows a heavey short did you CHECK the tube sockets ?? it's gonna happen again it can toast your output transformer warranty ain't gonna cover damage caused by tube failure and no maintainence this isn't SS plug in and forget it stuff..... Quote Link to comment Share on other sites More sharing options...
Coytee Posted January 9, 2005 Author Share Posted January 9, 2005 Ok, I'm back, been working on installing my fireplace in the bedroom all day. yes, had it about 3/4 done and then a much better way hit me, so I took it alllllllll apart. Ok, I'd not read your warnings prior to this and this is what's happened today nothing ! I turned it on earlier and worked "fine" so it's been on all day playing background music. I have read what's been said about the hard blow (I'm not gonna go there ) and the intermittent short. I'll call Jolida tomorrow and see what they tell me. It's been working/sounding fine all day, guess I'll go now & shut it down before I need to call the volunteer fire department out here again. (don't ask me about the 5 acre fire I had not once, but TWICE... Two weekends in row... the second week, I called the fire department, dude answered I said "Joe, are you one of the 23 guys that was out on that fire on Coytee Road last weekend??" "yep" he said "Well Joe, I need ya again") I'm now known as the local pyromaniac No one messes with me though for fear of... Quote Link to comment Share on other sites More sharing options...
Coytee Posted January 9, 2005 Author Share Posted January 9, 2005 Ok, I'm back, been working on installing my fireplace in the bedroom all day. yes, had it about 3/4 done and then a much better way hit me, so I took it alllllllll apart. Ok, I'd not read your warnings prior to this and this is what's happened today nothing ! I turned it on earlier and worked "fine" so it's been on all day playing background music. I have read what's been said about the hard blow (I'm not gonna go there ) and the intermittent short. I'll call Jolida tomorrow and see what they tell me. It's been working/sounding fine all day, guess I'll go now & shut it down before I need to call the volunteer fire department out here again. (don't ask me about the 5 acre fire I had not once, but TWICE... Two weekends in row... the second week, I called the fire department, dude answered I said "Joe, are you one of the 23 guys that was out on that fire on Coytee Road last weekend??" "yep" he said "Well Joe, I need ya again") I'm now known as the local pyromaniac No one messes with me though for fear of... Quote Link to comment Share on other sites More sharing options...
Coytee Posted January 9, 2005 Author Share Posted January 9, 2005 OH, and I DID pull the tubes & look at the socket, they all looked absolutely fine. Quote Link to comment Share on other sites More sharing options...
Duke Spinner Posted January 9, 2005 Share Posted January 9, 2005 Great ! .. then ... it's just a bad tube ! Quote Link to comment Share on other sites More sharing options...
3dzapper Posted January 9, 2005 Share Posted January 9, 2005 "Ok, I'm back, been working on installing my fireplace in the bedroom all day. I'm now known as the local pyromaniac" Playing with fire? Pun intended! Rick Quote Link to comment Share on other sites More sharing options...
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