(Topic ID: 194114)

Black Knight Project


By StratDoc

2 years ago



Topic Stats

  • 14 posts
  • 3 Pinsiders participating
  • Latest reply 2 years ago by StratDoc
  • Topic is favorited by 1 Pinsider

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#1 2 years ago

I picked up a really nice Black Knight Project. Boards are super clean and with some minor adjustments most everything is working with a few exceptions.

I cannot get the game to hold memory. It boots to 2500 3. I can force the game to start by opening the coin door and turning the machine off and on a couple of times. I have checked the battery holder and board and they both look really clean. No battery acid damage or bad traces that I can detect.

The second issue is the sound. The game has not sound either in diagnostic sound test or in game. Voltages on the sound board are correct. i double checked all connections and they look good.

The last issue is the coin door. I am not getting voltages to the coin door lights. I do not show continuity from the white/yellow plug connector on the driver board to the white/yellow connector in the cabinet.

#2 2 years ago

I'd guess you have a bad chip for the settings memory issue. Do you have power at the chip? If it comes to replacing it, consider putting an NVRAM kit in.

The sound issue might be the PIA on the sound board or maybe the amp is dead. See if you have an AMI branded PIA - they are notoriously bad. Do you get an audio thump when switching on? If not, consider the amp or speaker.

For the lights, if you have other GI I'd be thinking connectors, maybe bad sockets.

#3 2 years ago

I will check the power on the chip.

I do get an audio thump/buzz when starting the game.

I don't think it is the sockets because I am not detecting voltage to the sockets.

Quick update. No sound is produced from pushing the test switch on the sound board.

#4 2 years ago

Did you try adjusting the sound volume?

Take a look at the ROMS in the sound board to make sure they are secure. Check the sound ROM and CPU sockets to make sure the chips are held tight and that they are not Scanbe sockets. If they are, they should probably be replaced. Try slightly lifting the ROMs and CPU in the sockets and pushing them back down.

Do you have the smaller voice board connected to the sound board? Without that, the sound will not work at all.

#5 2 years ago

Yes, i have adjusted the volume both in the cabinet and on the board and still no sound. i will try your other suggestions tonight. When you say CPU sockets do you mean those on the sound board?

Yes, I have the smaller voice board connected to the sound board via the ribbon cable.

#6 2 years ago

Yes, I was referring to the ROM and CPU sockets on the sound board.

Make sure you have the volume on the speech board set somewhere in the middle. That is the balance between voice and sounds. If it is all the way one way or the other, you can't tell if one or both parts of the sound board are working (or not).

#7 2 years ago

The audio thump indicates you're getting power on the sound board and the amp is working. The advice on checking for Scanbe sockets is good. Like the AMI PIA chips, they are notoriously bad. Did you check the PIA brand?

If you have a logic probe or a scope, you could check both the CPU and PIA lines for activity.

#8 2 years ago

I replaced the battery holder - I had a spare that was good. This seems to have solved the memory problem - pin boots now to attract mode. However, it caused a new problem. I cannot get into diagnostic mode. The diagnostic switch is now not working. Strange because it was working prior to changing the battery holder when the pin was booting into diagnostic mode.

I haven't had a chance to check the sound issue.

#9 2 years ago

Those switches go through 2J13 on the driver board if I'm not mistaken. I think they're listed as the Special Switches and I believe they go direct to the CPU. I assume you pulled the driver and CPU boards to swap the battery holder. If so, I'd check the following things: 2J13 connector and header and the 40 pin interconnect. Look for cracked solder joints on both sides and you could lightly burnish the pins to clean them up a bit. I'd suspect the 40 pin first, especially if it hasn't been rebuilt. Those boards flex a lot when being handled and they're often old and worn out. That's typically one of the first bulletproofing steps recommended.

#10 2 years ago

Diagnostics now working. It was a connector as you suggested. I will work on the sound next.

The test switches and blanking led on the MPU don't work. Game is booting fine and enters a game fine. When I pulled the board I noticed that the IC just above the batteries had some corrosion on the legs - it is IC 24 a 7400 nand gate IC. It looks like the test and blanking go through that IC. I am wondering if that could be the problem.

#11 2 years ago

I could also use some advice on the displays. There are three displays - two player and the credit and ball display - and two missing player displays. The three displays work fine. I can purchase a full set of LED displays for what I can purchase 2 original plasma displays. What are your thoughts on keeping everything plasma versus going LED. I am leaning toward the latter.

#12 2 years ago
Quoted from StratDoc:

Diagnostics now working. It was a connector as you suggested. I will work on the sound next.
The test switches and blanking led on the MPU don't work. Game is booting fine and enters a game fine. When I pulled the board I noticed that the IC just above the batteries had some corrosion on the legs - it is IC 24 a 7400 nand gate IC. It looks like the test and blanking go through that IC. I am wondering if that could be the problem.

Certainly could be the problem. IC24 debounces the diag switch... I would use a meter to verify the switch is actually closing before replacing IC24

#13 2 years ago
Quoted from StratDoc:

I could also use some advice on the displays. There are three displays - two player and the credit and ball display - and two missing player displays. The three displays work fine. I can purchase a full set of LED displays for what I can purchase 2 original plasma displays. What are your thoughts on keeping everything plasma versus going LED. I am leaning toward the latter.

I'm a fan of the original Plasma displays but the LEDs will be far more reliable long term. You really can't tell how long the other displays will last.

You can offset the cost of the LEDs by selling your original, working plasma displays. Just take some good pictures of them running before decommissioning them.

1 week later
#14 2 years ago

I have been trouble shooting the problem of no sound.

I thought the problem was with IC10 on the sound board. Legs 22-36 pulse correctly on ic10 but legs 2-9 do not pulse and are locked eother hi or lo. I replaced ic10 with a new PIA and I still have the same issue. Legs 22-36 pulse correctly but legs 2-9 do not pulse.

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