mxzx
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Posts: 5
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Post by mxzx on May 11, 2017 10:58:11 GMT -7
We use an M12 at church and during rehearsal it died. Turned out fuse blew. Replaced fuse and still nothing. Ordered new tubes and did the troubleshooting as suggested on the Dr Z website and still nothing, no hiss, sound nothing.
It will occasionally blow fuse on initial power up, seems to be related to V2. When tube is pulled won't blow fuse as often.
I have checked and substituted cabs, cables, speaker, guitars, etc so it isn't any of that stuff?
I have worked on my Marshalls, but the Z is kinda new to me.
Any ideas of what to test, where to look? Everything on the inside looks as it should, no blown resistors, caps, etc.
Thanks!
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Post by bgkyt1 on May 11, 2017 12:26:33 GMT -7
does it blow on initial power up when the amp is on standby, or only when you go off standby? did you try a different rectifier tube?
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Post by DRZ on May 11, 2017 13:07:18 GMT -7
I agree with bgkyt1 . If it blows a fuse on power up 99% of the time it is the rectifier. Change the rectifier, I think the V 2 thing is a coincidence.
Z
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mxzx
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Posts: 5
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Post by mxzx on May 12, 2017 6:03:36 GMT -7
Initially it blew while playing, but now if it blows it is on initial power up. Never while switching from standby to play.
I changed the rectifier tube, and it still does it.
When the fuse holds, and during the test procedure for the rectifier tube; it looks normal powered up, no red plating, etc.
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Post by DRZ on May 12, 2017 7:44:51 GMT -7
Initially it blew while playing, but now if it blows it is on initial power up. Never while switching from standby to play. I changed the rectifier tube, and it still does it. When the fuse holds, and during the test procedure for the rectifier tube; it looks normal powered up, no red plating, etc. I'm a bit confused my the different symptoms that cause the fuse to blow. First you said it was on power up, now never on power up. Looks like it will need to be sent back to the factory for repair. Contact repairs@drzamps.com ask do for a RA form. Z
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mxzx
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Posts: 5
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Post by mxzx on May 12, 2017 7:58:00 GMT -7
No, if it is going to blow, it is on initial power up except the first time it blew while playing. It is also random, I just did some more troubleshooting and cycled the power 5 times or so and fuse held with all tubes in.
The standby switch has never caused a blown fuse.
There is no sound output of any type.
I did find the resistor across the input jack broken off at one solder joint, but that obviously isn't the problem.
Is there a chart that I can use to go through and test voltages, etc? We really hate to loose the amp for the time it takes to get it in and out of shop.
Thanks
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Post by benttop (Steve) on May 13, 2017 5:38:16 GMT -7
No, if it is going to blow, it is on initial power up except the first time it blew while playing. It is also random, I just did some more troubleshooting and cycled the power 5 times or so and fuse held with all tubes in. The standby switch has never caused a blown fuse. There is no sound output of any type. I did find the resistor across the input jack broken off at one solder joint, but that obviously isn't the problem. Is there a chart that I can use to go through and test voltages, etc? We really hate to loose the amp for the time it takes to get it in and out of shop. Thanks Fix the resistor and test again. You may be experiencing two different issues that confuse the diagnosis.
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mxzx
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Posts: 5
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Post by mxzx on May 13, 2017 19:52:18 GMT -7
I did fix the resistor. It will turn on and run now but still no output, I know the resistor has nothing to do with the fuse blowing.
I plan on using another M12 the church has to swap tubes to make sure that isn't it, then it will go back for service. I believe the warranty is 5 years, which this amp isn't that old.
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Post by DRZ on May 14, 2017 2:41:27 GMT -7
I did fix the resistor. It will turn on and run now but still no output, I know the resistor has nothing to do with the fuse blowing. I plan on using another M12 the church has to swap tubes to make sure that isn't it, then it will go back for service. I believe the warranty is 5 years, which this amp isn't that old. The factory warranty on a new dealer purchased registered M 12 is 3 years, 90 days on tubes. What is the serial # , and were did you purchase it ?
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mxzx
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Posts: 5
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Post by mxzx on May 14, 2017 20:04:45 GMT -7
Serial Z33287 Date of manufacture 1/15.
It was bought new, just not sure where.
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Post by simpleton on May 14, 2017 21:52:19 GMT -7
Serial Z33287 Date of manufacture 1/15. It was bought new, just not sure where. I had a repair sent into the Z shop...they had the repair done in a day and sent out the next. The shipping there and back took the longest.
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