Photo: pinballphotos
  1. » Forum
  2. » Tech
  3. » Tech: Early solid state
  4. » Gottlieb System 1 MPU...why is -12v turning into +12v?
(Topic ID: 234029)

Gottlieb System 1 MPU...why is -12v turning into +12v?

By Jakers

5 years ago


Topic Heartbeat

Topic Stats

  • 11 posts
  • 4 Pinsiders participating
  • Latest reply 5 years ago by TK2012
  • Topic is favorited by 1 Pinsider

You

Linked Games

Topic Gallery

View topic image gallery

IMG_8015.jpg
IMG_8012.jpg
IMG_8011 copy.jpg

You're currently viewing posts by Pinsider g-p-e.
Click here to go back to viewing the entire thread.

0
0
0
#6 5 years ago
 
GPE

G-P-E

GPE

US Omaha, NE

13y 76,800 2,778 4

Leads are reversed for the -12V.
Black lead always goes to common (ground).
Ground is connected to the positive end of the -12V cap (C17) so you need to put black lead to positive lead of C17, red lead to negative end.

0
0
0
#8 5 years ago
 
GPE

G-P-E

GPE

US Omaha, NE

13y 76,800 2,778 4

Could be bad CPU board but first verify voltages get to the display boards.
The 5VAC would be coming from the transformer and the 60VDC would be coming from the power supply board.

Promoted items from Pinside Marketplace and Pinside Shops!
$ 89.00
Electronics
Gottlieb System 1 Driver Board - LISY Development
That Old Pinball
 
$ 1.00
Pinball Machine
Roller Disco - To be Restored
Pinball Alley
 
Great pinball charity
Bringing the Joy of Pinball to American Children’s Hospitals
Project Pinball

You're currently viewing posts by Pinsider g-p-e.
Click here to go back to viewing the entire thread.

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, subscribe to Pinside+!

This page was printed from https://pinside.com/pinball/forum/topic/gottlieb-system-1-mpuwhy-is-12v-turning-into-12v?tu=g-p-e 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.