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Post by bluegrif on Oct 17, 2006 21:09:08 GMT -7
OK. I just bought a mint condition, used Maz 18 JR NR. It sounds great and functions absolutely perfectly until I put it on Standby and then switch it back to On. At which point I get nothing. A quick check showed it had blown the little 1/2 amp fuse. After powering down, then replacing the fuse, it again works fine, until I put it on Standby. Then once again, when I power on, nothing. Again if I power down and replace the fuse, it works fine. Since it works perfectly otherwise I can't imagine what the problem is. I'd really like to use this next gig. Is this going to need service? Or am I missing something?
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Post by johnnyl on Oct 17, 2006 21:40:14 GMT -7
Watch the power tubes when you switch it to standby next time. If you see an arc before the fuse blows then you probably have a bad power tube. If you've got an extra set of EL84's laying around you're all fixed.
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Post by bluegrif on Oct 17, 2006 22:57:05 GMT -7
Watch the power tubes when you switch it to standby next time. If you see an arc before the fuse blows then you probably have a bad power tube. If you've got an extra set of EL84's laying around you're all fixed. Thanks Johnny, but I tried replacing the power tubes with a pair I know to be good. Unfortunately, I don't have another 5AR4 Rectifier or I'd try replacing that. BTW, I can't believe I said 1/2 watt not 1/2 amp fuse.
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Post by yinielin on Oct 18, 2006 5:19:10 GMT -7
Mine did this and it was the rectifier tube.
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Post by Lefty on Oct 18, 2006 5:52:23 GMT -7
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Post by bluegrif on Oct 18, 2006 9:19:08 GMT -7
Thanks to all. Since I've replaced the EL84s, it does seem the consesus is it's the rectifier. I'll order one right away. Too bad it doesn't use the 5U4G, I have a spare one of those.
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Post by cheycaster on Jan 25, 2007 22:14:13 GMT -7
lemmee know if that fixed your amp as my NR Jr. is doing the same exact thing.
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Post by Seńor Verde on Jan 27, 2007 13:37:27 GMT -7
My Maz 18 Sovtek rectifier went bad last night and it blew the 2 amp fuse, before we even started paying. Fortunately, I carry a Weber Copper Cap, spare tubes and fuses. I put the Copper Cap in, a new fuse and played the gig. Tonight I will put a JJ rectifier and new output tubes in and see how that goes.
I hope yours is just the rectifier. Good luck.
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Post by deltone on Jan 27, 2007 20:03:13 GMT -7
Well, shoot. Same thing happened to me tonight (kind of weird that it's happened to a number of us in the same time frame). Switched to standby to change guitars and when I took it off of standby I lost the whole amp and never got it back on. After a quick check it appears the 1/2 amp fuse was blown and possibly the 2 amp fuse as well. I'm now fearin' a new rectificer tube is in order but I have none (that'll teach me). I'm fixin' to make a run to WallyWorld in hopes that they carry the fuses. How much for a good rectifier tube?
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Post by bluzsteel on Jan 28, 2007 11:36:21 GMT -7
Mine did this and it was the rectifier tube. +1
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Post by deltone on Jan 28, 2007 21:56:06 GMT -7
Well, don't waste your time at WallyWorld looking for fuses. They didn't have anything below a 10 amp fuse. So, tomorrow I'll be heading to radio shack. Anybody have any other suggestions on where to score low amp fuses?
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Post by heynewguy (Ol’ Bill) on Jan 29, 2007 4:22:46 GMT -7
I got all my fuses at Lowe's.
new
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Post by deltone on Jan 29, 2007 9:56:33 GMT -7
Lefty wrote: "Si, it would be the rectifier causing a surge to blow the fuse. Get a NOS 5AR4/GZ34 www.kcanostubes.com/content/estore_details.asp?category=28&product=149 from KCA. You'll never have to worry about the rectifier again...well at least for a long time. " If a good rectifier tube should last for a long time (some say for the life of the amp), I'm curious as to why we are blowing this tube? My amp is less than a year old. I assume Mike Z. puts a high quality tube in initially.
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Post by Lefty on Jan 29, 2007 12:42:16 GMT -7
Mike does put in a good current production rectifier tube, but it's still not up to NOS specs. With all the bumping around with shipping, and if you bought it used who knows how many hours are on it, it's quite hard to control the longevity of tubes after they have left the shop.
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