Mist multiball opto bases: the screws are 4-40 x 5/8 machine screws
The long Mist multiball opto bases are held by machine screws into a threaded plate under the playfield, not by wood screws as the parts list suggests. The right size is 4-40 x 5/8 inch, which any hardware store stocks if the originals go missing during a teardown.
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Games
Related tips
- Mist multiball long opto board dead: check L1 and the MPS-A77 transistor
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- Checking an under-playfield opto board for bad LM339s
Source: Pinball Repair help group!! (Facebook group)