Hi - All I was attempting a Monte Allums Tri-Gain plus mod when I ran into a problem. Part of the mod involves removing D3 and D4 then installing a switch in place of D4 which allows you to select Diode or LED distortion. I think I may have jumped the pad from D4 to J14 with some solder(I have since cleaned this up) when installing the switch. When I turned the pedal on and switched to LED, the LED went on then turned off. I have removed the switch and did not replace D3 or D4. Now it appears that I have some kind of voltage leak in the circuit where D4 used to be. It acts like there is a capacitor charging up and then as soon as the circuit is completed across the D4 pads, it immediately discharges. I can replicate this by touching the + and - D4 pads with a working LED. It comes on for a second then turns off. When I put a voltage meter across the D4 pads the voltage drops in the same way as it would when you bleed off the current from Electrolytic Caps in a tube amp before you start digging in.
I finally got it figured out. I downloaded a schematic and figured out exactly what the mod was doing (with the help of a friend who is an electronics engineer ).
Problem With Allums MT-2 Mod Tri-gain plus
Posted - 02/28/2010 : 02:54:13
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