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.
A schematic or manual for the above equipment would help!
Jack Willco Electronics