16198262 vs 1227730 vs 1227749

[Ludis Langens]

[Warning - lots of numbers ahead!]

A while back, I asked about the differences between the first two of
these.  Since then, I came across a bunch of '730's and one '749.  It
turns out that they are all essentially the same thing.

The circuit board in all of them is arranged the same.  The '730 circuit
boards have the part number "45C147" etched into the copper, and the
silkscreen contains the number "45B147".  The '749 has just the number
"73A667".  The 16198262 uses the number "73 667" (with a blank space in
place of a letter.)  Despite the PCB number differences, I believe they
are all a compatible layout.

Two of the '730's, at least one of which has an early 86 date code, have
a 16 pin DIP marked 45198.  In all the other 730's, and the '749 and
16198286, this DIP is marked 64992.  This 16 pin DIP is the only DIP on
the circuit board.

On the 45C147 boards, the (presumed) MPU is 16034980.  All of the
34980's I've seen have a date code from 1986 (8614 through 8648).  On
both 73*667 boards, the MPU is 16069664 and has a date code from 1987
(8721 and 8750).  See below for proof that this must be a compatible
production change.

All the other visible chips have identical numbers in all of these
ECM's.  These chips are: (160)34984, 34987, 34988, 45148, 45152, 45153,
45154, 54995, and 64606.

The '749 populates a few additional components.  Location U15 contains a
second 16034984.  It also has a second heat sunk FET and a bunch of SMD
resistors/capacitors/diodes.  However, the '749 is missing the
middlemost heat sunk quad driver.


I've found a pair of 1227748 ECM's (used with the 2.0 and 2.5 L4
TBI's.)  They share the following chips: (160)34984, 34987, 34988,
34993, 40669, 45148, 45152, 48504, 54995, 57245, and 64992.  One of
them, circuit board "46D799", contains the 16034980 MPU with a date code
of 8648.  The other, "73B490", uses a 16069564 with a date code of
8736.  Because these two ECM's are the same service number, the MPU must
be compatible.

There may be yet a third pin compatible MPU.  I've found a 1228321 ECM
which looks just like the '748's.  (It is used with the "other" 2.0
L4.)  It has the "73B490" circuit board, and all the major chips match. 
Except for the MPU, which is a 16079434, and the 16 pin DIP, a 79435.

[There, I can now dispose of my scribbled notes.]

               unsigned long BinToBCD(unsigned long i) {unsigned long t;
Ludis Langens     return i ? (t = BinToBCD(i >> 1), (t << 1) + (i & 1) + 
ludis at cruzers.com            (t + 858993459 >> 2 & 572662306) * 3) : 0;}