kiss boot prob (problem 1)

[RaMpAgE]

Kiss machine will not get the sixth LED flash (stops after the 5th)

I have replaced 555 timer, resistor R113, checked PIA as per below.

Any other suggestions before I handball it?

Cheers


Sixth Flash Completed*:
The Fakers Guide: a sixth flash means the PIA at U11 (6821) and the U12 timer (5550 chip is good. No sixth flash means either PIA U11 (6821) or its socket is bad, or the U12 (555) timer is bad. Lack of the 6th flash (five flashes only) can also mean a problems with the zero-crossing detector. Often this is the MPU board's R113 resistor (2k or 2.2k ohm, near the J4 connector) is open. This resistor takes the 43 volt DC coil power to the zero-crossing detector circuitry and normally runs hot. Hence it may eventually go open, so check it if only 5 flashes from the LED are seen.

Techno Guide: The U9 CPU chip monitors PIA2, port CA1 (U11). If transitions from high to low are detected, the CPU decides the Display Interrupt Generator is working. If U12, a 555 timer, or any associated circuit component fails, the CPU will not flash the LED the sixth time.

[Strangeways]

If the machine is on your test bench - you wont get a 7th Flash. If the board is in the machine, you need to test the voltages out of the Power Supply Board - specifically - for the +43VDC for the coils - I think it is TP5 ? Most likely a fuse.

[Pinball Fixers]

Do you still have the original IC sockets in the board? If so, the very first thing to do is replace them!

These give more trouble than anything else on the old Bally boards.

How did you check the PIA? Did you swap the two of them to see if the fault changed?

[RaMpAgE]

If the machine is on your test bench - you wont get a 7th Flash. If the board is in the machine, you need to test the voltages out of the Power Supply Board - specifically - for the +43VDC for the coils - I think it is TP5 ? Most likely a fuse.

I dont get a sixth flash mate, so better get that before the seventh. :)

[RaMpAgE]

Do you still have the original IC sockets in the board? If so, the very first thing to do is replace them!

These give more trouble than anything else on the old Bally boards.

How did you check the PIA? Did you swap the two of them to see if the fault changed?

All of the sockets are new except U14 & U8

PIA's checked with new ones.

[Strangeways]

If the machine is on your test bench - you wont get a 7th Flash. If the board is in the machine, you need to test the voltages out of the Power Supply Board - specifically - for the +43VDC for the coils - I think it is TP5 ? Most likely a fuse.

I dont get a sixth flash mate, so better get that before the seventh. :)

Sheesh.. Sorry about that !

I recall a similar issue where one of the tracks from U11 (lower of the PIAs) was cut - must have done that at the time that I replaced the socket. Double check your work around that area.

[RaMpAgE]

Yeah going over it I have noticed very tiny amount of corrosion under the ram socket - so I'll replace that one too and check all traces.

cheers