How to interpret the result of the switch test in Rack 'Em Up ?

After pushing the test button in the coin door until the display reaches 18, which is the switch test, seeing the following:
The display shows "18 00" and after a long pause displays "18 01". This continues, slowly counting every switch until finally 18 73 is displayed and then it stops there. Looked in the manual and that switch is a 10 point switch near the upper left sling. Checked that switch under the playfield and it doesn't appear stuck on. Checked the rest of the playfield switches, coin switches, trough switch and they all look good and not stuck. During the switch test, closing any switch seems to have no effect on what's being shown in display. Have repeated this switch test several times and it always does the same thing.

Based on the above it seems to be that MPU is seeing every switch as stuck closed? Struggling here and need help how to interpret this result? The manual doesn't give a detailed explanation of what's supposed to happen in a good switch test.

Background:
This Rack 'Em Up was mostly working within the last year or so. The only thing not working at that time was a few controlled lamps on the playfield never turn on.
Current situation is that the start button won't start a game. It will add credits though using the coin switch.
There are 2 playfield fuses (rightmost 2) blown when tested using voltmeter.
Things that have been done recently to troubleshoot: Have reseated the 2 connectors on the lower left of MPU coming from the cabinet wires which allowed the coin switch to start working. Ran a solenoid test and found no playfield solenoids firing, leading to checking the playfield fuses. Have not yet changed any of those fuses. Playfield fuse issue should have no relation to the switch problem, or does it?
MPU is original and has no signs of corrosion.

Problem solved by replacing the fish paper. It was blowing chips on the mpu related to the switch matrix so those had to be replaced.