I am wondering if your board is booting in the first place. Normally sys11 boards will give you some sort of error code presenting itself via the diagnostic led.
Hope this helps you narrowing down the issue.
System 11a, 11b, 11c Diagnostic Flashes.
These games do not have a 7 segment display. Instead there is a LED which indicates the memory chip test being preformed. To start the memory chip test, turn the game on or press the bottom CPU diagnostic switch button SW2 on the left side of the CPU board. Quickly count the CPU board LED flashes of the middle (diagnostic) LED, and compare them to the follow chart.
Flash
Display Message
Explanation
1 U25 RAM Failure U25 RAM could not be used. No other tests are performed; the game is locked here until the problem is fixed.
2 Memory Protect Failure This message means: (A) the coin door may be shut; (B) the Memory Protect switch may be stuck in the ON position; (C) the Memory Protect logic is protecting the audit memory; (D) a U25 RAM failure is occurring. Note this test assumes the coin door is OPEN since this test is initiated ONLY by pressing the CPU diagnostic switch (SW2).
3 U51 PIA Failure 6821 PIA at U51 has failed. *
4 U38 PIA Failure 6821 PIA at U38 has failed. *
5 U41 PIA Failure 6821 PIA at U41 has failed. *
6 U42 PIA Failure 6821 PIA at U42 has failed. *
7 U54 PIA Failure 6821 PIA at U54 has failed. *
8 U10 PIA Failure 6821 PIA at U10 has failed. *
9 IRQ Failure IRQ has malfunctioned. It may be missing or too slow or too fast.
10 U27 ROM Failure The ROM (or EPROM) at U27 did not pass its internal checksum. This could be a ROM failure, or its associated components and connections may be causing this problem. U26 ROM test is skipped.
11 U26 ROM Failure The ROM (or EPROM) at U26 did not pass its internal checksum.
* Alternatively, the PIA's associated connections or components are causing the PIA to appear bad.