After installing the Gus 3-cap mod on two MXL 991s, one of them isn’t working. I think it may be the something on or around the gate that’s the culprit. I’ve tried several different capacitors. I’ve tried resoldering the other side also.
I don’t really know how to use a digital multimeter other than for voltage. With the mic body and capsule off, the working mic reads around 30v across C3 and also C4 (which we’re also changed) and it hums pretty loud because it’s not grounded to the body.
On the non-working mic it’s like 3 or 4v across C3 or C4. When I touch a post on the gate, a 1G resistor, the lead from the FET to the gate post, or the gate cap with one of the DMM leads, it starts to hum like it should. Otherwise, it makes no noise.
Can anyone help me figure out how to fix it?
I don’t really know how to use a digital multimeter other than for voltage. With the mic body and capsule off, the working mic reads around 30v across C3 and also C4 (which we’re also changed) and it hums pretty loud because it’s not grounded to the body.
On the non-working mic it’s like 3 or 4v across C3 or C4. When I touch a post on the gate, a 1G resistor, the lead from the FET to the gate post, or the gate cap with one of the DMM leads, it starts to hum like it should. Otherwise, it makes no noise.
Can anyone help me figure out how to fix it?