(Topic ID: 200206)

Black knight power supply cap

By Pinfected

4 years ago



Topic Stats

  • 7 posts
  • 3 Pinsiders participating
  • Latest reply 4 years ago by G-P-E
  • Topic is favorited by 1 Pinsider

You

Linked Games

#1 4 years ago

I am getting ready to replace the large capacitor in my black knight’s power supply. I have a brand new 35v 27000 mfd capacitor available. Can I safely use it or is it rated too high. The current one is 20V 18000 mfd. I do not want to stress any of the other components on the board so if I need to order a new cap I will. Thanks in advance for any help. Mike

#2 4 years ago

Going higher on the voltage rating is not an issue, whatsoever.

Going that much higher on the capacitance is not a good idea for most circuits but since in this circuit, it is simply a filter capacitor, you should be just fine.

#3 4 years ago

Thank you Schwaggs. Hopefully this will solve the game crashes I’m experiencing. Cap looks pretty old. I’ve already replaced the inter board connector. If this doesn’t solve the problem I’Lloyd’s have to look at game rom sockets next.

#4 4 years ago

Good luck! Don't forget to look for cold solder joints on all the header pins. Reflow the solder on all header pins and replace any header pins that look like they overheated.

#5 4 years ago

100% working after replacing the cap. Good reminder about the cold solder joints. I have found a surprising number of issued by were solved by reflowing the solder joints on header pins: from display, sound, switch matrix and power issues. Thanks again for your help. The Black Knight rides again!

#6 4 years ago
Quoted from Pinfected:

100% working after replacing the cap. Good reminder about the cold solder joints. I have found a surprising number of issued by were solved by reflowing the solder joints on header pins: from display, sound, switch matrix and power issues. Thanks again for your help. The Black Knight rides again!

Very cool! Congrats on the fix!

#7 4 years ago

The problem with going to a huge capacitor value (18000 is huge, 27000 is huge-er) -- they result in enormous but brief current spikes through the bridge rectifier diodes at a rate of 60/sec. Make sure you have beefy diodes/bridge rectifiers in there when using these large caps.

Promoted items from the Pinside Marketplace
$ 45.95
Eproms
Pinballrom
$ 129.00
Cabinet Parts
Bob's Pinball Stuff
$ 44.99
Cabinet - Shooter Rods
Pinball Shark
$ 89.95
Cabinet - Shooter Rods
Super Skill Shot Shop
$ 17.00
$ 125.00
Cabinet - Toppers
Sparky Pinball
From: $ 77.00
Tools
Pincoder Store
$ 959.00
$ 599.95
Lighting - Led
Pin Stadium Pinball Mods
From: $ 18.00
Apparel - Men
Pinside Shop

Reply

Wanna join the discussion? Please sign in to reply to this topic.

Hey there! Welcome to Pinside!

Donate to Pinside

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, become a Pinside+ member!