Replaced fried 5w resistor on the magnet resistor board. (Magnet and lighting for the ‘snake’ element at the upper left side of the play field)

Cleaned rear drop targets

Applied stickers and reinstalled front drop targets and saudered an errant loose wire on the back of the second target assembly.

The drop targets are catching ever so slightly on the bumper rubber behind them, i think this can probably be fixed by cheating/ bending the posts that hold the bumper back just a hair……

Started sorting out lights. Tested bulbs in ABC and pit 5000-50,000. Cleaned the bulbs and lenses, which were filthy.

Some bulbs did not come on. Traced problem to plug for connector 2J5, lamp column drive. Needs to be replaced.

General cleaning of the play surface and plastic overlays. Changed out most of the rubber rings. The upper left corner of the board still needs rings swapped out (remainder of ring kit on machine).

Repinned and replaced connector 10J4, sound board remote volume. Didn’t help.

Debugging the sound board:

• fuses are good
• input power is good
• on-board regulator and voltage converter is good; test points all have approximately correct voltages
• checking the speaker output with the oscilloscope shows nothing
• same for the output of IC1

Reading further, the sound board signal gets sent to the speech board for mixing with speech and then comes back for output.

Continued!

Experimenting more, the sound sometimes works and sometimes doesn’t.

By going through the diagnostics in the Williams 1980 Solid State reference manual, it appears that the problem is on the speech board. Symptoms:

• if I jump the negative pole of C29 to 10J4 pin 1 and press the self-test, I get one cycle of electronic sounds
• It says that the likely problem is address or data connection to the speech module, or that IC6 is faulty
• Checking Table 13, which is for a slightly different problem, it says to check for data activity on sound board IC 10 pin 39 and speech module IC1 pin 12 or 13 (depending on version). Neither of those pins have activity.
• I checked the data and address lines on IC6 on the sound board and they all seem ok, so that’s getting
• Swapping IC10 from Blackout solved the problem. Both speech and sound work. So I’ll order the part.