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Post by Paul (TRANE) on Jul 28, 2008 6:33:17 GMT -7
Greetings,
Well my band played an outdoor gig last night and my amp shut down about halfway through the first set. I did a quick check and the mains fuse was blown. Used a back up amplification method for the rest of the night.
When I got the amp home I did some troubleshooting. I pulled the chassis and checked the screen grid resistors and the like and all seemed to be well internally. So I replaced the mains fuse and the amp powered up, until I turned the standby switch to on. At that point the amp made a buzzy sound and then just died.
After scratching my head a few minutes I changed out the power tubes, rectifier and the mains fuse again. Amp powered up and had no issues when taken out of standby. So, then I decided to see if the rectifier could have been the issue. Took the new rectifier out and put in the one from the gig and the amp works just fine. Putting the power tubes from the gig back in causes the amp to blow the mains fuse again.
The GT-KT 66C tubes are only a month old so I will be sending a note over to GT about them. Not sure what caused them to go out but that is how tubes can be some times.
So did I miss anything in my trouble shooting? Seems like it was the power tubes. Let me know if there is anything else I should do trouble shooting wise....or other.
Thanks
Paul G.
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Post by dixiechicken on Jul 28, 2008 14:25:02 GMT -7
DC here! To me it seems as one or maybe both powertubes are the culprit. Post the question to Myles - just in case. Cheers: Diciechicken!
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Post by Deleted on Jul 28, 2008 18:44:28 GMT -7
DC here! To me it seems as one ot maybe both powertubes are the culprit. Post the question to Myles - just in case. Cheers: Diciechicken! +1 Didn't you just put those in to replace the Gold Lions that went bad on ya'? Might be something else going on. You might want to check with Mike Z also. Just out of curiosity, do you bias hotter than 40mA?
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Post by Paul (TRANE) on Jul 29, 2008 6:48:15 GMT -7
I was wondering about something internal. I went through the usual suspects for such issues and did not find any problems with the inside. Seems to be quite the bullet proof design.
As for bias I usually wind up right around 38mA. I do not like the sound any higher than that. These were only in the amp for about 30 days total.
As for the Gold Lion tubes that I did have in there before I was told there was a manufacturing issue with the tubes from the date code I had in there originally. So that would explain the Gold Lions. The GT-KT66C tubes...not sure....hopefully will not happen again. Right now I have a set of Gold Lions in from 08 01 which is a good date code from all reports thus far.
Actually played the amp last night and it did wonderfully. Sounds like a million bucks again. Keeping an eye on it though..... tubes are not perfect.
Paul G.
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Post by Deleted on Jul 29, 2008 17:29:51 GMT -7
Are the GT's still uder warranty? If so that's good.
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Post by Deleted on Jul 29, 2008 17:30:39 GMT -7
Hopefully everything will be fine with the new tubes.
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Post by Paul (TRANE) on Jul 29, 2008 18:15:41 GMT -7
Yep they are under warranty. I contacted GT and Myles and Rick have been really helpful. I have an RA number and will be shipping them back soon. Have to get time to get to UPS and ship them to GT.
I think that all should be well with this set based on all I have seen thus far.
Paul G.
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Post by Deleted on Jul 30, 2008 15:27:40 GMT -7
Yep they are under warranty. I contacted GT and Myles and Rick have been really helpful. I have an RA number and will be shipping them back soon. Have to get time to get to UPS and ship them to GT. I think that all should be well with this set based on all I have seen thus far. Paul G. That's good news
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