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Post by fingersmcginty on Mar 1, 2022 9:24:03 GMT -7
Hi all, I was having somw fun with the maz today and then suddenly i have no sound at all. The power led is active, i presume it must be a tube that's bad? I had a look at the rear of the amp and one of the power tubes isn't glowing.
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Post by fingersmcginty on Mar 1, 2022 9:25:05 GMT -7
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Post by fingersmcginty on Mar 1, 2022 9:30:42 GMT -7
I've just rep;laced the tube and the new one is glowing but still no sound. I've check ed the fuses ast the back and it looks like the 1/2A fuse is blown....would this be normal?
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Post by headshrinker (Marc) on Mar 1, 2022 10:05:37 GMT -7
Yes, the fuse blowing protected the rest of the amp. Likely either one of the power tubes went and/or the rectifier went and maybe took out a power tube. The power tubes should be replaced with matched pairs. When you get fuses, get several, as you may blow a few looking for a problem. There is a Dr Z trouble shooting video on the site somewhere. I'm sure someone else will post it for you.
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Post by nick0 on Mar 1, 2022 11:02:31 GMT -7
Yes, the fuse blowing protected the rest of the amp. Likely either one of the power tubes went and/or the rectifier went and maybe took out a power tube. The power tubes should be replaced with matched pairs. When you get fuses, get several, as you may blow a few looking for a problem. There is a Dr Z trouble shooting video on the site somewhere. I'm sure someone else will post it for you. Here you go!
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Post by Ridgeback on Mar 1, 2022 12:10:29 GMT -7
It's most likely a tube but I used to toss my cables and other small stuff into the back of my Maz combo. One time we were setting up and I couldn't get any sound out of the amp even though everything checked out. Turns out I had disconnected one of the speaker spade terminals when stashing stuff in the back of the amp. Figured it out just in time for the set but I felt pretty foolish in hindsight for not checking the speaker connections earlier. For several years after that I always soldered my speaker connections.
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Post by j4gitr (John) on Mar 1, 2022 13:47:51 GMT -7
I had a very similar experience with my Maz18. Turned out to be a rectifier causing the problem. Still follow the trouble shooting guide as presented in Nick0 post.
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Post by fingersmcginty on Mar 1, 2022 13:49:20 GMT -7
Thanks folks....I will replace the 1/2 amp fuse tomorrow and report back.
My indicator light is actually on though and the 1/2 amp fuse is blown .
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Post by fingersmcginty on Mar 1, 2022 14:26:50 GMT -7
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Post by fingersmcginty on Mar 1, 2022 16:36:07 GMT -7
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Post by Chilly Gibbons (Todd T.) on Mar 1, 2022 16:56:04 GMT -7
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Post by fingersmcginty on Mar 1, 2022 16:59:04 GMT -7
I had bought them before your comment . It's good that you're recommending them Quite expensive but hopefully they'll last.
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Post by fingersmcginty on Mar 2, 2022 9:57:31 GMT -7
OK so the amp is powering up and seems toi be fine. Would it be OK to leave the spare EL84 that i had in the amp umntil the matched pair arrive? Presume it's OK but just want to be sure.
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Post by headshrinker (Marc) on Mar 2, 2022 10:09:20 GMT -7
If it were me, I would leave it in, but keep an eye on the power tubes to make sure they don't red plate or do something else odd. I would also keep an ear on it and if things started to not sound as they should, shut it down and wait. I'm pretty brave about these sorts of things having been brought up on tube amps and having found they are quite robust about things being off from specs causing major problems.
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Post by purpletele on Mar 2, 2022 11:56:03 GMT -7
Thanks folks....I will replace the 1/2 amp fuse tomorrow and report back. My indicator light is actually on though and the 1/2 amp fuse is blown . Not sure how the light could be on it the fuse had blown. Sounds like you got around it though.
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Post by Chilly Gibbons (Todd T.) on Mar 2, 2022 12:00:56 GMT -7
If it’s not humming too bad then the spare might actually be matched close enough to the original. The issue you run into with unmatched tubes in cathode biased amps is primarily hum.
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No sound
Mar 2, 2022 12:11:58 GMT -7
via mobile
Post by fingersmcginty on Mar 2, 2022 12:11:58 GMT -7
Thanks folks....I will replace the 1/2 amp fuse tomorrow and report back. My indicator light is actually on though and the 1/2 amp fuse is blown . Not sure how the light could be on it the fuse had blown. Sounds like you got around it though. I have one of the older maz amps with 2 fuses. 500mA and a larger one ...2A I think. Its only if the larger fuse blows you won't have any power indication.
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Post by purpletele on Mar 2, 2022 17:26:20 GMT -7
Not sure how the light could be on it the fuse had blown. Sounds like you got around it though. I have one of the older maz amps with 2 fuses. 500mA and a larger one ...2A I think. Its only if the larger fuse blows you won't have any power indication. Right, I forgot about that set up. Thanks
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Post by fingersmcginty on May 18, 2022 5:38:01 GMT -7
Maz is up and running again thanks ....
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Post by daddyelmis (Greg) on May 18, 2022 7:01:52 GMT -7
was it the 500ma fuse?
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Post by fingersmcginty on May 18, 2022 14:48:40 GMT -7
it was a bad tube which sequentially blew the fuse also.....now it's time to get the cure up an running.
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