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Post by Norrin Radd on Apr 28, 2017 13:57:04 GMT -7
When I am playing it (issue started just a couple days ago) it will play just fine for a while and then the volume will drop by about 80% and sometimes sputter and then come back to full volume and then repeat. It is intermittent but becoming more frequent.
Am I looking at a power tube issue? Pre-amp tube? Rectifier? Something else?
Yes - the current tubes in there are ALL old. They have all been in there at least 2-3 years (except for the EL84s, which are about 18 months old.)
Any suggestions on which tube/s might be the issue? Where to start replacing first?
Good news is I have replacements for all of them except the EL84s, but I can get those rather easily. I'm just really looking for where to start - which is the most likely suspect? And then the next? etc... I don't want to yank the whole bunch at once if I don't have to. That seems wasteful.
Thanks!
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Post by digs57 on Apr 28, 2017 15:01:10 GMT -7
try v1 first...
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Post by doctorice on Apr 28, 2017 15:06:32 GMT -7
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Post by headshrinker (Marc) on Apr 28, 2017 15:38:09 GMT -7
Drops in volume and then returns to normal could be that the input jacks or send and return jacks for the effects loop, if it has one, have become oxidized. Spray them with deoxit or something similar, being sure to get the little contact if it has a shorting switch on it. If you put a shielded cable between the input and output jacks for the effects loop and it goes away, it's likely there. If it has two inputs and you only regularly use one, go into the other one, if it goes away it's likely the one you are in.
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Post by DRZ on Apr 29, 2017 3:14:48 GMT -7
Drops in volume and then returns to normal could be that the input jacks or send and return jacks for the effects loop, if it has one, have become oxidized. Spray them with deoxit or something similar, being sure to get the little contact if it has a shorting switch on it. If you put a shielded cable between the input and output jacks for the effects loop and it goes away, it's likely there. If it has two inputs and you only regularly use one, go into the other one, if it goes away it's likely the one you are in. +1000 , good call as always Marc. Z
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Post by Norrin Radd on Apr 29, 2017 4:03:47 GMT -7
Thanks for the all the advice everyone. I will be troubleshooting this afternoon, contact cleaner in hand!
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Post by Norrin Radd on May 3, 2017 15:00:17 GMT -7
Drops in volume and then returns to normal could be that the input jacks or send and return jacks for the effects loop, if it has one, have become oxidized. Spray them with deoxit or something similar, being sure to get the little contact if it has a shorting switch on it. If you put a shielded cable between the input and output jacks for the effects loop and it goes away, it's likely there. If it has two inputs and you only regularly use one, go into the other one, if it goes away it's likely the one you are in. +1000 , good call as always Marc. Z Both correct! This was absolutely 100% the right answer. Thank you Marc! I got to really put her through her paces today and test out. I had used contact cleaner on all the jacks on the amp - all of 'em. That was the only thing I did and I cannot reproduce the problem no matter how hard I try or push the amp (if it had an 11 on it, I would have hit it today. ) I also only ever use the Hi input so am suspecting that may have been the culprit. Regardless, it certainly didn't hurt to clean out all the jacks in any case. Thanks for the advice, Marc - much appreciated!
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Post by tronus on Jun 4, 2017 14:59:50 GMT -7
Can the Send/Return jacks cause this intermittent cut out without anything plugged into them?
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Post by BritInvasion on Jun 4, 2017 19:11:12 GMT -7
Can the Send/Return jacks cause this intermittent cut out without anything plugged into them? Yes it can.
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