Williams Black Knight (Williams, 1980) Few questions about Black Knight and System 7

[bonedoc]

I am trying to finish up repairing my black knight, system 7 and have a few questions. Please fill in any blank spots you can. Here are my issues:

-When I turn the game on, it goes into attract mode, no errors. New power supply. Everything is receiving the right power. How do I start a game? My displays dont work, do I cant tell what is going on, but pushing the start button to the left of the coin deposit does nothing.

-My displays dont work. Getting proper voltage, but a couple of the HV drivers are BLAZING hot....I assume I just need to replace these?

-Many times, when I power the game on, it goes into attract mode anf the Multi-Ball solenoid rhythmically fires about every 2 seconds. Pushing the diagnostic button stops this, as does unplugging the switch inputs on the driver boards. Anyone seen these? Maybe a short somewhere? I read one spot where someone mentioned the game wont start and will fire this solenoid if it is not sensing the right start up conditions, like number of balls.

-My CPU has a couple DIP switch banks on the upper left. For the life of me, I cant find the use for these, and they are not in the manual. I know they are from early system 7 games. Anyone know what they are for.

Please help!

 

[faralos]

system 3 thru 6 and system 7 fixes can be found here:

http://pinball.flippers.info/system6resources.asp
I hope this helps as I know nothing at all about the actual repairing of your pin

 

[bonedoc]

Ok, I have a couple things figured out.

-The PIA for the switches is pretty jacked. It looks bad. Several of the pins are bent up and soldered back on. I tested the incoming and outgoing wires from the driver. No shorts to ground, and I cant seem to find a shorted diode. So, I ordered a new PIA.

-When I do the diagnostic test, I get error 8, which is the 5101 ROM. I dont know if this is correct. I ordered one anyway. When I shut the door, I get error 9....which is the door shut code.....maybe this is why it wont start, but I doubt it.

-I have a brand spanking new power supply. For whatever reason, the +100V is right on. However, the negative side is around -120V...is this too much for the display driver chips?

 

[spalmer]

Your bad PIA may be causing the game not to start. If the switch PIA is bad, it certainly may not be seeing the start button. It could also cause a false code 8 on the diagnostics. As for the displays, on those machines, the 100 volt goes directly to the displays and does not pass through the display driver chips. Turn off the lights and see if the displays have a faint glow in the lower left corner of each display. If so, they are getting the correct voltage and the displays themselves are likely in good shape. If the displays are glowing, run a jumper from TP4 to TP9 on the MPU board. If the displays light up you have a blanking signal problem. The bad PIA could also cause the displays not to work. The blanking signal tell the MPU board that the PIAs are working. Bad PIA, no signal. The 40 pin interconnect between the MPU and driver board on these is pretty problematic. Pin 37 of that connector is the Blanking signal. It should read somewhere around 4 volts. I restored a Black Knight a while back and have a spare rebuilt driver board (with a brand new 40 pin interconnect) that I do not need. PM me if you are interested. It might be a little easier than trying to track down multiple issues with yours. It would certainly solve your switch matrix issues. If you want to try and rebuild yours, I would be happy to call you and give you some pointers.

 

[bonedoc]

Hey, I replaced the vertical PIA on the far right and put in a refurbished display driver board. After doing this, all of my solenoids work with the solenoid test and I have displays! ....but a couple problems.

-My Player 1 and Player 2 displays are not turning on. But, if I swap the cables out with the displays that work, they do indeed work, so, all the displays are functioning, but obviously not receiving data.

-When I power on, Player 3 and 4 flashes on and off once. Then the high score display Just shows an "8". Does this make sense? Also, when I do a display test, it starts at all 9s, goes to all 8s, and then loops. Does any of this make sense?

How much do you want for your driver board?

 

[spalmer]

Makes sense. There are 2 UND7180 chips on the master display board IC1 and IC2. If these are bad, it can cause the issues you are describing. I have $80 in the driver board after it was repaired by Rob over at Lock When Lit, however I will entertain a reasonable offer for it.

 

[bonedoc]

I just tested those. I ended up doing a diode test on them. I hooked red to the ground and back to each pin. Everything looked good. Also tested the resistors...those are all good...

I noticed one weird thing. On the MPU, there are two 4700 Ohm resistor arrays. They are all pulled up to 5V. I assume the PIA activates each strobe by pulsing these output lines to the master display board by pulsing them low.

Anyway....Pins 2 and 4 of IC29 are reading about 1K. These go out to strobes 10 and 12. On IC28, pin 4 is also doing this. This is strobe number 12. I dont know how this would affect things. I assume the lower resistance would pull it up harder and make it harder to strobe low.

What is also strange....The freaking DIP switches. I have seen NOWHERE where these are explained. I believe they are also hooked into these resistor arrays.