edgibbs

Hey All :) Again, another round of big thanks to uedat125!!! I'm back to contribute my help and pay it forward too :) I finally got my M9 repaired last Thursday after work on my workbench there. I took me about four hours bench-time over a handful of days since my last post to weed out what was all wrong inside of my M9. My original problem was that the unit looked and acted fine but there was no throughput audio when any effect was enabled - only bypass audio when the true-bypass option was selected in the setup menus. So what happened was some sort of large signal or impulse came in through the Left (Mono) guitar input which shorted U9 TL074 which then took out the -12Vdc rail U19 NJM2374A regulator & D25 BAT54 schottky-diode, the +12Vdc rail D23 BAT54 schottky-diode, the CODEC IC U17 CS42432 which shorted out it's +5VA IC U20 LM7805. So, whatever the errant signal/impulse was, it poked quickly through to the CODEC IC a.k.a., analog-to-digital and digital-to-analog converter IC and knocking out the associated power regulator circuitry. I bought all of the repair parts through Mouser.com :) Google: "line 6 M9 schematic" :) Enjoy, Dan Gibbs :)

A Correction to the D23 part identification by uedat125 - D23 is a BAT54 Schottky Diode, Not a 2SC1623 Transistor :) Hello to All and a hearty THANK YOU to uedat125!!! uedat125 is potentially saving me $100-200!!! His sharing of this info is a gift from God through uedat125. As with uedat125s unit, everything functions but there is no effected-audio coming through at all. I reflashed the unit with V2.04.00 firmware yesterday afternoon and there was no change - I was hoping that would fix it and it did not. Last night, I did a google-search for "Line6 M9 mainboard" and ran across this post. I just took my M9 apart again and I can see that D23 is burnt and possibly R120 as it looks to have smoke residue on it although I haven't grabbed my meter and verified that yet. I found the schematic for this unit and it says that D23 is a BAT54 schottky diode with SMT marking of L4. I looked up the part number that uedat125 found and it too is marked L4 for the lower Hfe version...he chose the L6 medium-Hfe version of the transistor as I can see that in the second photo. The proper SMD marking should be L4P as shown in On Semi, Vishay, and International-Rectifier datasheets but, some manufacturers are only putting L4 on the diodes which caused uedat125 to think that it is a transistor. I have attached a photo-snip of the schematic showing D23 in the upper right. Again, a great-many THANK-YOUS to uedat125 for sharing his repair-finding on this, Dan Gibbs :)