Prop synchrophaser issues in C-130 Technical Posted July 28, 2010 This bird has had this problem come back a few times - not repeat/recur though. Basically, the props wont sync with No. 3 selected as master. Replaced valve housing, no fix. Repalced synchrophaser, no fix. Shot wires on sync rack - all are good. Shot all pins on all plugs on valve housing, tach gen, and pulse gen, and all are good. The last time this happened we found wires in the wrong spots on the terminal board on the electrical rack (TB1C, I believe). After we fixed that, it op checked good. This was a month or two ago. Now the problem has returned. Engine shop replaced the syncrophaser and now they're telling us the problem has gotten worse - it won't sync at all with either prop selected. Obviously the first thing to do is check and see if it's a bad part out of supply. But in every case we've had this issue, the system tests OK with the sync tester set. Anyone got any ideas?