Intermittent black squares printing from Pioneers to 82240B

[Dave Britten]

Alright, did some more tests. The 27S is the only one exhibiting the character dropping, and only with the B.

Some dates inferred from serial numbers:

27S - 1988
17BII - 1992
19BII - 1993

82240A - 1989
82240B - 2002 (Am I reading that right? It's ID25200071.)

That's some big enough gaps that I could conceivably see the timings and tolerances having changed since the 1st-gen Pioneers.