After a shop-out the mystery wheel no longer turns in play or in wheel test, its opto can't be made to register in switch test, and the wheel test shows an 'H' whatever position the wheel is in. A jumper test at the MPU shows the switch input itself works.

Mystery wheel won't turn and its opto never registers: reflow the power supply headers

Cause: Cracked solder joints on the power supply board header pins were starving the wheel board of 12 V, so neither the stepper motor nor its opto worked.

Checks

• Check for 12 V at the wheel board.
• Tug each wire gently at the wheel's Molex plug; wires can break inside the crimp while looking connected.
• The wheel's stepper motor is driven by two solenoid transistors on the CPU board, so check those if power is good.

Fix

• Reflow (or repin) the header pins on the power supply board, then retest the wheel.

Systems

• Williams System 11B

Games

• Cyclone

Related tips

• Random resets, days or minutes apart: burnt power supply AC input connector
• Mystery wheel loses its place: wheel motor control board diodes or opto
• Low +5 V (below 4.9 V) from the power supply
• What the System 11 power supply board feeds
• Power supply board fuses (typical game)
• Rebuilding the +100 V section of the power supply
• Rebuilding the -100 V section of the power supply
• GI connectors left the power supply after Cyclone

Source: Pinball Repair help group!! (Facebook group)