DATAMATH CALCULATOR MUSEUM
|The printed circuit board
of the original SR-50A
design makes use of a TMS0521 SCOM chip.
| Early SR-51A calculators mounted the second SCOM chip in a
piggy-back manner on the first one.
|In the last production year
of the SR-50A it uses the same PCB as the late SR-51A and SR-56 Programmable.
The new SCOM chip reads TMS0531.
|The redesigned SR-51A
sports two SCOM chips
TMS0532 and TMS0533. Please notice the empty
space for the Memory chip of the SR-56.
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© Joerg Woerner, June 7, 2005. No reprints without written permission.