Black Knight - no solenoid power

[Black Knight]

Forgive me if this is covered elsewhere - I have been searching for a while and not come up with anything suitable so thought I'd start a new thread.


Have an early Black Knight - with the older system 6 power supply.  Had the machine nearly 30 years and in all that time never had an issue that's stopped the machine for too long - usual stuff with switches, a couple of solenoids, loose connections, dry joints, etc.


I lost all solenoid operation a while ago, so switched it off and left it - a couple of years later, I thought I'd try and fix it.  Run all diagnostics and most things are fine, but just the solenoids have no power - I've tried what I usually do when I have an issue and remove and reseat all connecters and plugs.  Still nothing.  Although I haven't tested anything with a meter yet, thinking the power supply could be dodgy?  I've never replaced a cap or anything on it, so some TLC may be required.


Any thoughts or does andyone have some schematics of the system 6 power supply - and even system 7 schematics in general as I've never had any nor needed them.


Thanks in advance - BK.

[pinnies4me]

Fuse F2 is solenoid power on a Sys 6 - 2.5 amp slow blow, so probably the best starting point.

[Black Knight]

Thanks - yeah I've checked the fuses - I have blown that one before when a solenoid shorted out some years back but nothing so simple this time.  I'll have to run my meter over the board and make sure I've got voltage where it's supposed to be (or at least where I think it should be - I don't have any details on the power supply so I'll only be guessing)


Cheers - BK

[Steevsee]

Manual and schematics are available at the pinball database.
https://www.ipdb.org/machine.cgi?id=310

[Black Knight]

Manual and schematics are available at the pinball database.
https://www.ipdb.org/machine.cgi?id=310

Thanks so much - have everything I need from there now including the schematics for the system 6 PSU so I can go from there when I get a moment. 👍😊

[Strangeways]

Always check fuses out of circuit. Also check the fuse clips themselves for proper tension. Check output voltages are correct and if they are, could be a dry joint on the connector, or a daisy chained solenoid wire is loose on a coil.

[Black Knight]

Well, could have saved us all some drama if I'd bothered taking the PSU out for a closer look - the fuse holder for F2 had cracked from the board and open circuited.  Resoldered all the joints and treated it to some new caps while I was at it - We have power!  Solenoids operate fine, but have another issue which I'll take a closer look at and see if I can fix before asking for assistance - the outhole switch isn't working or the outhole solenoid isn't firing, not sure which yet, will take a look on the weekend.


Thanks for everyones help. 👍

[beaky]

i have seen quite a few of those power supplies with cracked joints on the connector pins.glad to see u have it up and running.

[Maycle]

hello i just bought a Black Knight project machine. it blows the i think its F2 fuse. its the middle one on the fuse card. if i unplug every connector on the power supply board except the 2 power input plugs it still blows that fuse. so i think its something in the power supply board ? is this right ? and if so what should i look at next ? its the earlier bk with the sys 6 boards not the sys 7 boards