Parts on the A5 auxiliary supply

A5 runs from 12.6 VAC and makes +12 and -12 V for the sound boards (LM7912 for the negative side) plus +5 V from an LM340T (7805). It carries an MC3403 op-amp (LM324AN or NTE987 substitute) and the two TDA2040 audio amplifiers; TDA2030s fit but give less power.

Systems

• Gottlieb System 3

Related tips

• No sound after the 12 V plug went on the speaker lead
• No sound, or weak sound
• No sound at all: check the -5 V regulator
• Both sound board LEDs dark
• The A20 auxiliary sound board
• A5, A6, A8 and A20 plug identification

Source: Repairing Gottlieb System 3 Electronic Pinball Games from 1989 to 1996, Clay Harrell (pinrepair.com)