DataEast 128x32 Display Controller #520-5055-00/#520-5055-01 PAL Chips.
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These two chips are custom PAL chips used on the 128x32 
dot matrix display controller board #520-5055-00 and 
#520-5055-01. A specialty PAL burner is needed to burn 
these 20 pin PAL chips.

Location U2  (file PAL16R4.U2) : TIBPAL16R4-25 CHECKSUM 50D8.
Location U16 (file PAL16L8.U16): TIBPAL16L8-15 CHECKSUM 6489.
(I used the slower -25 speed for U16 and it worked OK.)
