Re: Blackout switch matrix problem

An update on this.

I replaced the column's 7046 and both row 4049s. Also replaced the
PIA (with a 68B21 ). Sockets all around.

When I powered the game up, it wouldn't boot. I reseated the driver
board again, and it came up. The 40 pin connector between the
mpu and driver boards is likely marginal and needs to be replaced.

Another switch problem I had was that the game would sometimes start
a two player game when you hit the credit button once. The points
on the credit button were very tarnished and wouldn't clean up with
a business card. I replaced the blades and points, and that
solved the problem. Here's a picture of the old blades/points:

http://www.kaosol.net/~swensonj/station1/blackout/DSCN0382.JPG

I used some novus 2 to clean the point for the picture. You can see the
gold plating was pretty much gone from these points.

- Jim

===============

I'm working on a switch matrix problem on a Williams Blackout. No
switches in column 6 register. I pulled the connectors from the columns
and rows pins on the driver board and jumpered the column 6's pin to row
pins in switch test, and none register. So, it's something on the
board. Switches in other columns are working, though I haven't
gone through them all thoroughly.

I buzzed out the paths from column 6's pin to the output of the PIA,
and they're all fine:

http://www.kaosol.net/~swensonj/station1/blackout/DSCN0378.JPG

So, at this point, would the next step be to check to see if the
PIA is outputing on that pin and if the 7406 is too? Need to run
to radio shack and get a logic probe I guess.

The one thing I got confused about for a while was my Blackout manual
shows two 7406s used for the columns, while my board just has a single
7406. I guess it makes sense, since Blackout only uses columns 1-6
in the switch matrix. Do I have a system 6 driver board or something
else? Was thinking maybe it's a system 7 board?

- Jim

----

You can do a quickie check of the 7406's and 7408's as described in Clay's
guides. Goes a long way towards diagnosing switch matrix problems.

The system 3 through 7 driver boards are basically the same with minor
differences (changes in resistor values for the lamp matrix, and on system 7
some jumper wires replacing resistors in the switch inputs) so pretty much no
matter which one of the drivers you have in your Blackout, the revision isn't
what is causing your switch matrix problem.

Richard

----

The diode test definitely shows something. Readings taken with the chip
mounted on the board:

All the input legs (1,3,5,9,11,13) on the 7406 read .591. The output
legs (2,4,6,8,10,12) are around .870-.890, except for leg 8, which
reads 1.892. And that's the output leg for column 6.

- Jim
.