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I have a Mission 5E3 kit that was working great last night (and I was playing it pretty hard). Today, I fired it up, played a few notes and after a few seconds -- nothing. The power tubes are still glowing, and I checked the heaters and the voltage is correct. But there is no B+ to be found anywhere, maybe 1 V. I'm figuring the rectifier just blew, correct?
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Im no expert but it sounds likely. Check for AC before the rectifier. If it?s there then you?ve found your problem -
AC is fine. 343 V on each of the Hi-V leads, 6.7 V across the filaments. Pilot lamp works fine. Any ideas on what would cause a rectifier to blow before the fuse?Comment
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Okay, I figured it out. I had the power cord tied to pin 1, which I thought was unused (lug 3 on the socket had broken off). I guess it's not. I moved the power cord to pin 7 and everything works fine now.Comment
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I think that pins 1,3,5, and 7 aren't used on that socket...Comment
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There is no reason why using lug 1 would not work as well as 3, 5 or 7.Originally posted by GBStratman View Post
As mentioned above, there is no element of the 5Y3GT connected to lugs or pins 1, 3 5 and 7 so any would work fine as a terminal tie point.
Here the bad news, if there was always filament heat, you didn't fix anything by moving the power cord wire from 1 to 7.
I suspect it is merely a bad solder joint somewhere (mostly lug 8 or 2 of the rectifier socket) and moving the chassis and wires around has temporarily fixed it.Comment
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Thanks, Bruce. I think you're right, because it's still doing it, although it only happens when I turn the amp on. If I wiggle the rectifier tube a little in its socket, it comes on and then stays on. I'm not sure if it's a bad solder joint or bad contact between the socket and the tube pins. I'll try reflowing the solder, and if that doesn't work, replace the socket.Originally posted by Bruce / Mission Amps View PostComment
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