Black Knight
Williams, 1980I have been working through a number of issues on a Black knight. The latest issue I have encountered is the F2 fuse blowing once a game starts and connector 2J9 is connected. When this connector is disconnected the fuse does not blow and I can play a full game
Looking at the manual it looks to control mainly magnet relays, coin door lock out and bell.
I am not sure where to start looking with this, any advice on where to start on this one is greatly appreciated.
if you have enough fuses.
Take each coil out of circuit until you find the issue.
Of course it could be the transistor related to that coil.
Or check the ohms on the coil see if which one could be shorted out.
Remove J2-9
With the game off, measure the resistance between the coil side lug of the F2 fuse holder on the power board and each of the pins in the J2-9 connector. Red lead on the fuse holder or you will forward bias the coil diodes and get close to zero ohms on all the pins. This is an easy way to measure the resistance of the wiring and the various coils. If you find one that is less than 5 ohms, you know where to start looking for either a bad coil, bad diode, or shorted wiring.
Pin 1 Q35 - Special Relay
Pin 2 Q37 - Nothing
Pin 3 Q39 - Nothing
Pin 4 Q41 - Nothing
Pin 5 Q43 - Bell
Pin 6 Q45 - Coin Lockout
Pin 7 Q33 - Right Magnet Relay
Pin 8 - Key
Pin 9 Q31 - Left Magnet Relay
Quoted from Schwaggs:Remove J2-9
With the game off, measure the resistance to the coil side lug of the F2 fuse holder on the power board for each of the pins in the J2-9 connector. This is an easy way to measure the resistance of the wiring and the various coils. If you find one that is less than 5 ohms, you know where to start looking for either a bad coil, bad diode, or shorted wiring.
Pin 1 Q35 - Special Relay
Pin 2 Q37 - Nothing
Pin 3 Q39 - Nothing
Pin 4 Q41 - Nothing
Pin 5 Q43 - Bell
Pin 6 Q45 - Coin Lockout
Pin 7 Q33 - Right Magnet Relay
Pin 8 - Key
Pin 9 Q31 - Left Magnet Relay
Thanks for sharing this process, this looks a much quicker and easier way to diagnose this type of issue.
Found the issue, this one has a issue with the Bell coil.
Quoted from martymart:Thanks for sharing this process, this looks a much quicker and easier way to diagnose this type of issue.
Found the issue, this one has a issue with the Bell coil.
Excellent! Let us know what ends up to be the root cause of the problem!
Thank you everyone for your help so far.
I have now resolved the F2 fuse issue. I found that the bell solenoid was faulty. I replaced it with a new one and now I can play a fully functional game.
However I played around 5 games and then had what looked to be a reset. After that I lost all the displays. I have checked all the fuses and made sure all the cables were seated properly. All of these look ok.
Any ideas on where to look next to fix this next problem.
Thanks in advance.
Quoted from martymart:Thank you everyone for your help so far.
I have now resolved the F2 fuse issue. I found that the bell solenoid was faulty. I replaced it with a new one and now I can play a fully functional game.
However I played around 5 games and then had what looked to be a reset. After that I lost all the displays. I have checked all the fuses and made sure all the cables were seated properly. All of these look ok.
Any ideas on where to look next to fix this next problem.
Thanks in advance.
Have the 40 pin male and female connectors been replaced? A must if it hasn't.
Quoted from chad:Have the 40 pin male and female connectors been replaced? A must if it hasn't.
Agree. Plus reflowing solder to all the header pins on all the boards (often have cold solder joints) and checking the ROM sockets (often worn out after all these years).
Replaced the header pins on the CPU board and at this stage everything looks to be holding up ok for the moment. It looked like a heap of cold and cracked solder joints.
Hopefully can now close this one out.
Thank you everyone for your help.
Did you have to remove the coil to test it?
Quoted from martymart:Thanks for sharing this process, this looks a much quicker and easier way to diagnose this type of issue.
Found the issue, this one has a issue with the Bell coil.
Where do you find this information what each pin does?
Quoted from Schwaggs:Remove J2-9
With the game off, measure the resistance between the coil side lug of the F2 fuse holder on the power board and each of the pins in the J2-9 connector. Red lead on the fuse holder or you will forward bias the coil diodes and get close to zero ohms on all the pins. This is an easy way to measure the resistance of the wiring and the various coils. If you find one that is less than 5 ohms, you know where to start looking for either a bad coil, bad diode, or shorted wiring.
Pin 1 Q35 - Special Relay
Pin 2 Q37 - Nothing
Pin 3 Q39 - Nothing
Pin 4 Q41 - Nothing
Pin 5 Q43 - Bell
Pin 6 Q45 - Coin Lockout
Pin 7 Q33 - Right Magnet Relay
Pin 8 - Key
Pin 9 Q31 - Left Magnet Relay
Quoted from SomeCaliGuy:Where do you find this information what each pin does?
This info is in the schematics for the game. You can download them from IPDB.
I'm looking at the schemtic, but I don't see where it says what each pin controls. I'm looking at page 16, 20, and 29 but I do not see it. What do the 9 pins do on 2J11?
Quoted from Schwaggs:This info is in the schematics for the game. You can download them from IPDB.
https://www.ipdb.org/machine.cgi?id=310
Quoted from SomeCaliGuy:I'm looking at the schemtic, but I don't see where it says what each pin controls. I'm looking at page 16, 20, and 29 but I do not see it. What do the 9 pins do on 2J11?
Check the top of this page--the info you're looking for is there:
Screenshot_20211121-120513.pngWanna join the discussion? Please sign in to reply to this topic.
Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!
This page was printed from https://pinside.com/pinball/forum/topic/black-knight-connector-2j9-blows-f2-fuse?hl=martymart and we tried optimising it for printing. Some page elements may have been deliberately hidden.
Scan the QR code on the left to jump to the URL this document was printed from.
Goodrich, MI