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So the "high" channel on my mig100 isn't working. The "lo" channel works fine, but on the high channel there is hardly any sound. Narrowing it down, it looks like it is probably one of the capacitors around the socket for the preamp tube that makes another gain stage. I am going to try replacing them, but if anyone has any other suggestions or has had this problem before, i'd love any input. Also, if anyone has a schematic for the 100 they could send me it would be great. I've just been going by the schematics for the 50 and the 100h.
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I'm too lazy to look up the drawings. is this one of the models where the high gain jack goes through an extra gain stage? The low gain jack has cutout contacts, and when you are NOT plugged into ut, those contacts carry the signal through from the output of the first high gain stage. Check the low gain input jack.Education is what you're left with after you have forgotten what you have learned. -
yes, the high gain jack goes through an extra gain stage, but i'm not sure i understand what you're saying. does the high gain stage have similar cutout contacts?Comment
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No. It is like an effects loop sorta. The high gain jack is normal, like any amp. It feeds into the first gain stage. The output from the furst gain stage then goes to the low gain jack cutout contact. If nothing is plugged into the low jack, then the tip contact and the cutout contact are together and they complete the circuit, and the signal continues on into the low gain stages and the rest of the amp.
The cutout contact is the extra one on an input jack. It is the one that grounds the tip contact when the jack is empty in the Fenders. Look at the standard open frame jack like on most Fenders. There is a large J shaped piece that touches the tip of the plug. Then there is the extra blade next to it. The J and the extra blade are touching, until you plug into the jack. Plugging in moves the J thing over a little and it no longer touches the extra blade. That extra blade is the cutout contact. When the jack is empty, those two must touch AND make reliable electrical contact. If they don't the signal won't flow through.
The high gain input adds the extra stage. All it does it add it in in front of the whole rest of the amp. It does this right at the low gain input.
Push on the contacts on the low gain jack and see if the sound returns when you do. That would verify my theory.Education is what you're left with after you have forgotten what you have learned.Comment
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so it looks like something was at one point soldered to the connection, so even when the jack is closed, the circuit is not. if anyone has a schematic that would be really really helpful.Comment
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