(Topic ID: 306305)

Gottlieb System 1 Power Supply, No -12V

By Nchezey_5916

2 years ago



Topic Stats

You

Linked Games

Topic Gallery

View topic image gallery

78203967-1E14-45C6-8CAF-512A8B618D8C (resized).jpeg
AE729DD7-12BC-4DFE-AFCD-4A99F068325A (resized).jpeg

#1 2 years ago

If you’re not interested in the back story feel free to jump straight to my question at the bottom

I just purchased my first pin in non-working condition. It’s a 1978 Charlie's Angels SS. Everything seems to be original aside from a ghetto rigged power/free play switch that was installed at some point. The only other information I have on it is that the outhole coil fires and sticks on the second you flip the power switch (I have not powered it on for more than a few seconds due to this).

I decided that I would start by doing a diagnostics test to make sure everything is getting proper voltage. I began by testing the bridge rectifiers and they both tested sweet. I then moved on to the power supply board and ran into my first problem. The board says the left 2 pins should have 5v (they do), but the far right pin which is supposed to be -12v reads nothing.

Can someone please tell me what no reading on the -12v pin means? Am I going to need a new power supply or is there somewhere else I should start?

Thanks in advance!

AE729DD7-12BC-4DFE-AFCD-4A99F068325A (resized).jpegAE729DD7-12BC-4DFE-AFCD-4A99F068325A (resized).jpeg
#2 2 years ago

I always test the bottom board completely first. You already tested the bridges so that's good. Test each voltage at each side of each fuse clip before you move on the power supply

#3 2 years ago

The -12 volt regulator is the off board device next to the red lead tip.
Once the board is removed from the backplate parts can be easily replaced and solder connections inspected for cracks.

#4 2 years ago

to be able to keep testing, and not worry about the coil staying energised, you can remove a wire from the coil

#5 2 years ago
Quoted from Cheddar:

I always test the bottom board completely first. You already tested the bridges so that's good. Test each voltage at each side of each fuse clip before you move on the power supply

Good call! Voltage was consistent on both sides of all the fuses but it looks like I may have some work to do with the capacitors. I’ve only got 16.5v on wires 6 and 7 going from the capacitor to the power supply and it’s supposed to be 69v! (also got a few low readings on the larger capacitor as well but that shouldn’t be causing my power supply voltage issue)

Once I get the capacitor issue figured out I’ll see if I get my -12v at the outgoing side of the power supply.

78203967-1E14-45C6-8CAF-512A8B618D8C (resized).jpeg78203967-1E14-45C6-8CAF-512A8B618D8C (resized).jpeg
#6 2 years ago

L

#7 2 years ago
Quoted from pinballdaveh:

The -12 volt regulator is the off board device next to the red lead tip.
Once the board is removed from the backplate parts can be easily replaced and solder connections inspected for cracks.

That is very useful information, thanks. Hopefully I won’t have to get into soldering boards on my first pin I’ll give it a whirl if it comes down to it though!

#8 2 years ago
Quoted from Nchezey_5916:

That is very useful information, thanks. Hopefully I won’t have to get into soldering boards on my first pin I’ll give it a whirl if it comes down to it though!

maybe a misunderstanding......but being 'off board' doesn't mean it's not soldered to the board, it's 'off board' in the sense that it's isolated from the board onto the mounting bracket that acts as a heat sink.
there's only 3 points of solder on the power supply board so maybe a good chance to start?
the -12V regulator is the top component held to the L shaped mounting bracket with a nut and screw.

#9 2 years ago

The 5 volt and the -12 volt outputs are each protected by their own over voltage crowbar.
A zener diode and scr circuit that shorts out the output when over voltage is sensed to protect the boards from the higher voltage.

Promoted items from the Pinside Marketplace
$ 4.00
Playfield - Decals
UpKick Pinball
Decals
$ 7.50
Electronics
That Old Pinball
Electronics
$ 89.00
Electronics
That Old Pinball
Electronics
From: $ 5.95
Playfield - Protection
The Pinball Scientist
Protection
From: $ 2.99
$ 65.99
Lighting - Other
The Pinball Scientist
Other
$ 37.00
Gameroom - Decorations
The Flipper Room
Decorations
Great pinball charity
Pinball Edu

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-power-supply-no-12v 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.