CPC ERRORS SM 74 6+L

I have Hiedelberg SM 74 6+L. Machine is not running. In CPC it is showing init test 3 error i.e. EAK_01 FDFF error. I checked all the safety switches and interchanged all eak board cards but condition still remains the same. Someone help please

 

Hi sir:
Hope you are well
Your indication fault:
Check:
Failure to production testing in I / O- HF
Test:

1) Fault of the differential inputs.

2)Upper loop test terminated with fault (it is possible that the
plug-in contacts X1E, X1A, X2E, X2A on the EAR got mixed
up).

3) Defect Timer Flip Flop.

Finally due this:

1) Perform a visual inspection : look for loose and broken wires, improperly seated connectors, loose or broken wires misset switch, missing jumpers. and so on.
Chech for obviously damaged component(components burned or discolore due to overheating);

2) Reseating Boards and components:
Edge connectors are a common souorce of problems. Power down the system and remove the PC boards. Examine the edge connector
for contamination and clean with contacts cleaner contacts. Reseat any loose components 9suc as scoketed ICs) . Reseat the
boards and power up.

3) Power supply checks:
Check the power supply for missing voltages and voltages out of spec. A digital multimieter DMM can be necessary, as
voltage specifications are quite tight: logic supplies for example: must be within + 0.5 percent of 5Vdc. All the
multiple supplies and all must be checked.

4) Board swapping:
Board swapping involves the substitutiono of a known godd board for a suspect one.

5) Clock for CPU:
Check the frecuency with frequency counter or a DMM included frecuency counter( like Fluke DMM)

6)Reset CPU:
reset cpu see the attached schematic.

 

Fix it?
Did you do the test ?