Re: Tech Williams sys. 3 problem

On Jan 2, 8:42 pm, Jason Cross <jmacr...@xxxxxxx> wrote:
On Jan 2, 8:02 pm, "Popbumper1" <munsonju...@xxxxxxxxxxxxx> wrote:



Jason:

  IF the system is working correctly, you should be able to go through all
the numbers, and as soon as they "start over", quickly power down and up
again - all displays will show zeroes if you go in attract.

  If this does not work, the 5101 CMOS RAM needs replacing.

Chris

"Jason Cross" <jmacr...@xxxxxxx> wrote in message

news:9ad6e2d8-b038-4b3e-8172-a6645ce3ca01@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

I picked up a Disco Fever today.  At first it would not do anything
except GI at power on.  Both lights on the cpu stayed on.  I reset the
chips.  Now the cpu comes up, GI on, both lights come on then go out,
all displays are on.  The master displays has 01 on one side and 04 on
the other.  I can go through the numbers with the red button in the
coin door.  Game will not go into attract.  I put new batteries in and
the battery holder is brand new.  Any ideas?- Hide quoted text -

- Show quoted text -

Just went out and tried again.  I can turn it on and it goes into
audit.  If I flip it off and back on quick I can get it to come up
where all displays are zeros. The high score light is flashing on and
off with the rotation of the high score in display one.  There are
random playfield lights on, nothing sequencing or flashing all that
are on are on steady.  when I push the button to try and credit up all
goes blank and both lights on the cpu come on.

Ok Jason, you still have the memory problem either with battery power
reaching the 5101 or a 5101 problem. On IC 19 - the 5101 check the
voltage at pin 19. You need 3.9VDC minimum to hold the info in RAM.
If it looks ok, socket and replace the 5101.

Now while you have the board out of the machine, the 40 pin .156
inter-board connector between the CPU and the driver is the next
likely cause of your CPU lockup. Any flakey connection along this bus
will lockup the CPU. The recommended fix is replacing the driver
board female connector - and better yet also the male pins on the CPU
board. If you are lucky just a remove and replace operation might
provide a adequate connection for you to continue to debug the game.
You can also re-flow solder the connectors, driver board and CPU board
while the board is out. The flexing associated with removal of the
driver board causes cracked solder joints.

It appears your CPU board is OK - except for the RAM problem, driver
board is possibly OK but not a sure bet yet. The other possibility
for the CPU lockup is a weak power supply on the 5VDC causing the CPU
to go down.

Barry
.

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