Fault route
ZX7-160/200 Output Diode Short No Arc Diagnostic
A secondary-output route for compact ZX7 machines where inverter power exists but arc output is missing or abnormal.
Quick Answer
If the machine powers up but no arc output appears, a secondary output diode short/open can mimic drive or transformer failure. Check the middle-board output diode group, transformer secondary, reactor and output terminals before replacing the top inverter board.
Diagnostic path
Power indicator/fan OK → drive evidence → main transformer secondary → output diode group → reactor → shunt/feedback → terminals.
Evidence table
Shorted output diode: low or collapsed output, protection or heavy load. Open diode path: missing/weak DC output. Reactor/shunt fault: unstable or weak current. Top board replacement should wait until secondary faults are excluded.