Leave the big lamp filter capacitor unless it is leaking
The large backbox lamp matrix capacitor is hard to find. Only replace it if it leaks or bulges, or if F3 and the lamp bridge are good and the lamps still misbehave; measure the transformer AC output before blaming it.
Systems
Related tips
- Replace the +5/+12 V logic filter capacitor
- Spare diodes, capacitors and resistors for System 3-7
- Judging the logic filter cap by AC ripple
- Display supply low (under 90 V) after the resistors are changed
- Cross the legs when MJE15030/15031 replace SDS201/SDS202
- High-voltage supply rebuild parts, System 3 to 11C
- Fitting the high-voltage kit
- Early Black Knights use the System 6 power supply
Source: Repairing Williams System 3 to System 7 Pinball 1977 to 1984, Part Three, Clay Harrell (pinrepair.com)