JODY
Active member
From the power cable that plugs into the power board to the TIP120/102 it measures 4 ohms, the same as the coil by itself so I assume all is well now on the playfield. I'm pulling the boards to replace the 7408 and TIP102.
Black Knight Board Problem - Drop Target Coil
- Thread starter JODY
- Start date
JODY
Active member
The drop target is working great now. Thanks for everyone's help.
Some new issues though.
Some new issues though.
Last edited:
JODY
Active member
Upon turning the machine on after reinstalling the boards it went into audit mode instead of attract mode. I had read this was bad.
Following information on this site
http://www.pinrepair.com/sys37/index2.htm#factory
was able to start a game by cycling through test mode 50 twice.
Before I bought the machine, someone had put an external battery holder in it and installed 4 batteries instead of 3 and a diode / wire. I had removed one battery and installed a diode while working on the board. Tested the + and - pins on the memory chip and the voltage appeared fine so thought maybe the memory chip had gone bad. After messing around for awhile running the cpu board diagnostics and looking at other things went back to test the pins on the memory chip again. They had no voltage this time. No voltage at test pin 7. Traced it to a bad connection where the + battery lead was soldered to one of the old battery terminals. The battery terminal was very corroded and only one strand of wire of the + battery lead was not broke. Restripped the wire and soldered it directly to the board.
Game still came up in audit mode. Pressed the CPU diagnostics button on the CPU board and it went into attract mode. Turned the game off. Waited awhile. Turned it back on and it went into attract mode. This issue is fixed.
The only remaining issue is the back left flipper no longer works. It also worked prior to removing the boards. No disconnected wires. Haven't looked at it further yet.
Following information on this site
http://www.pinrepair.com/sys37/index2.htm#factory
was able to start a game by cycling through test mode 50 twice.
Before I bought the machine, someone had put an external battery holder in it and installed 4 batteries instead of 3 and a diode / wire. I had removed one battery and installed a diode while working on the board. Tested the + and - pins on the memory chip and the voltage appeared fine so thought maybe the memory chip had gone bad. After messing around for awhile running the cpu board diagnostics and looking at other things went back to test the pins on the memory chip again. They had no voltage this time. No voltage at test pin 7. Traced it to a bad connection where the + battery lead was soldered to one of the old battery terminals. The battery terminal was very corroded and only one strand of wire of the + battery lead was not broke. Restripped the wire and soldered it directly to the board.
Game still came up in audit mode. Pressed the CPU diagnostics button on the CPU board and it went into attract mode. Turned the game off. Waited awhile. Turned it back on and it went into attract mode. This issue is fixed.
The only remaining issue is the back left flipper no longer works. It also worked prior to removing the boards. No disconnected wires. Haven't looked at it further yet.
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Jimjaycee
Member
You probably have hairline cracks on the pin connectors for your flippers on the driver board.
Just reflow the solder on the pins and hopefully the issue will be solved.
Just reflow the solder on the pins and hopefully the issue will be solved.
Lindsey
Well-known member
If that were the case I would expect both flippers in the pair to not work. There are 2 sets of contacts inside the flipper relay. Each set provides the ground path for one side of the flippers (one set of contacts for the left pair, one for the right pair).
The positive side of the circuit is a different story. If you look at the schematics you will see individual positive wires for each flipper. I would start by checking for positive solenoid voltage and ground at the flipper. If one is missing trace it back to where the problem lies. If they're both present your coil has gone open most likely due to the small wire breaking at a solder lug. Note that you will only have ground at the flipper when the flipper relay is energized and the cabinet switch is pressed (playing a game).
Flipper circuits are really not that complicated. I'm sure you'll figure it out.
JODY
Active member
Found the problem with the top left flipper. Voltage to the flipper was 0. Started looking for wire problems under the playfield. Only thing that looked suspect was the blue wire that runs from the upper flipper to the lower. It didn't look great where it attaches to the lower flipper Pulled at it and it appeared to be fastened by melted insulation and only one or two strands of wire.
Cut it off, restripped, and soldered. Flipper works great.
Couldn't resist playing a few games even though it needs new rubbers, cleaning, replacement of several flippers due to cracks in the plastic, and a wax job. This game is funner than I thought with the timed drop targets and having to monitor both upper and lower playfields during multi-ball when balls are on both playfield levels.
I'll have to keep my eyes out for more bad wire connections. It looks like whoever repaired it in the past loved to drip solder wires. I've had to reflow many solder connections under the playfield and in the process of fixing the issues in this thread resolder two other wires that fell off.
Cut it off, restripped, and soldered. Flipper works great.
Couldn't resist playing a few games even though it needs new rubbers, cleaning, replacement of several flippers due to cracks in the plastic, and a wax job. This game is funner than I thought with the timed drop targets and having to monitor both upper and lower playfields during multi-ball when balls are on both playfield levels.
I'll have to keep my eyes out for more bad wire connections. It looks like whoever repaired it in the past loved to drip solder wires. I've had to reflow many solder connections under the playfield and in the process of fixing the issues in this thread resolder two other wires that fell off.
