I'm looking for a custom IC marked 528 55178 it's used in a motorola
S1344AAB Frequency Counter/Auto Tune Deviation Meter. The Motorola
part number is 51-80329A60

In the early 70's the unit was Manufactured by Systron Donner for
Motorola. Systron Donner's model number was SLN6407A-75. They also
manufactured a frequency counter model 6252 that is identical to the
counter section of the 1344AAB

The chip is a counter/latch with tri-state outputs. I was able to
Identify some input ie clock and output enable carry. But the other
inputs are unknown.




Jack
Willco Electronics