(Topic ID: 218025)

Freddy, GI in backbox issue, strange one!

By PghPinballRescue

6 years ago



Topic Stats

  • 9 posts
  • 5 Pinsiders participating
  • Latest reply 8 months ago by Sonic
  • Topic is favorited by 2 Pinsiders

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#1 6 years ago

I have a client who bought a Freddy, Nightmare on Elm Street pin recently.
Gottlieb System 3, if I recall correctly.

The GI in the head went out, so I was called to fix it.
It was very hot in his house, so I was a little rushed to get it diagnosed, and I am sure I overlooked something, but here are the steps I took:

DMM set to AC, and I was getting 3V from GND to the socket (normal since I was measuring from ground).
Checked the fuses, checked the connectors, checked the grounds, everything appears to be perfect.
Checked the GI relay (relay A if I recall) and I have proper voltages theres.
Checked the voltage at the backbox connector on the door, voltage checks OK.
Flashers in the backbox work (I know they are on another circuit).
I then pulled every bulb out of the backbox, and put a single LED in, and it worked fine, so I loaded up the backbox with LEDs, and they were nice and bright.
I charged the client and went home.
He called me a day later and said they were out again.

So, any ideas on what to check from here?

The GI in the rest of the machine is just fine, its ONLY the backbox.

#2 6 years ago
Quoted from PghPinballRescue:

Checked the GI relay (relay A if I recall) and I have proper voltages theres.

The GI in the rest of the machine is just fine, its ONLY the backbox.

I would double check anything and everything to do with that GI relay first (relay, soldering, connectors):
No Backbox General Illumination.
If the backbox General Illumination is missing, of course first check the A12 transformer panel fuse F8. If this fuse is Ok, then check the backbox GI (A) relay. The "A" relay has a single normally closed switch which completes the power path to the backbox GI. Sometimes the A relay switch can get mis-adjusted and cause the backbox GI to never work.
http://www.pinrepair.com/sys3/#gi

#3 6 years ago
Quoted from wayout440:

I would double check anything and everything to do with that GI relay first (relay, soldering, connectors):
No Backbox General Illumination.
If the backbox General Illumination is missing, of course first check the A12 transformer panel fuse F8. If this fuse is Ok, then check the backbox GI (A) relay. The "A" relay has a single normally closed switch which completes the power path to the backbox GI. Sometimes the A relay switch can get mis-adjusted and cause the backbox GI to never work.
http://www.pinrepair.com/sys3/#gi

I will check the relay again with a much closer look. I had to temporarily lock the relay on with a wedge because in attract mode the relay is off more than it is on. Very annoying when trying to diagnose a voltage issue.

Fuse F8 is good. The client had even checked it before I showed up. I pulled it and checked it, it passed.

#4 6 years ago

I seem to recall that I had one or two bad GI bulbs causing all them to be out in the backbox when mine was out. If that is the case, then they are all in series. Then again, might had been adjustment to the 'A' relay that did it.

#5 6 years ago
Quoted from PinballManiac40:

I seem to recall that I had one or two bad GI bulbs causing all them to be out in the backbox when mine was out. If that is the case, then they are all in series. Then again, might had been adjustment to the 'A' relay that did it.

Socket problems are also a common problem, so yes - one defective bulb can do,it as well

Unfortunately it appears that Gottlieb was using organic flux when they were building the system 3 machines. The problem with this flux is it can be conductive (this info came from an ex-Gottlieb designer). For example when Stargate came out there were reports that 1/3 of all machines that out of the box had some kind of light problem. After locating the socket that was causing the problem it could be easily moved around and cracking type of noise heard, indicating a short..

#6 6 years ago
Quoted from wayout440:

Socket problems are also a common problem, so yes - one defective bulb can do,it as well
Unfortunately it appears that Gottlieb was using organic flux when they were building the system 3 machines. The problem with this flux is it can be conductive (this info came from an ex-Gottlieb designer). For example when Stargate came out there were reports that 1/3 of all machines that out of the box had some kind of light problem. After locating the socket that was causing the problem it could be easily moved around and cracking type of noise heard, indicating a short..

Well over 2 years ago when I fixed my Freddy backbox GI light issue and I just happened to see a couple of bulbs that turned black but I happened to had messed with the relay adjustment the same day too. Luckily, my Stargate hadn't had any GI issues since I had it for about 7 years now.

#7 6 years ago

The contacts on that A GI relay are highly suspect. Put a jump wire on it for test (short across the terminals for the backbox lighting) and see if they come on. If so, the contacts need to be cleaned or adjusted. I had a Freddy do that, the contacts were misaligned but appeared to be touching. It was intermittent until I worked no the contacts. Now Freddy has backbox lights. I am afraid of the dark.

3 weeks later
#8 6 years ago

Solved!!!!

Problem was not with the relay. Jumped the switch contacts and the voltage was still low, and the lights still did not light. I was very optimistic though!

The problem was a the single white wire leading off of the connector in the backbox to the back of the light board. There's a set of 3 ring terminals that screw into the wood on the back of the board.

The input wire was a tiny bit burnt and acting like a resistor. I cut the terminal off, wired a newer gooder one in its place a BINGO BANGO, we're in business!

Thanks to everyone for your input and suggestions.

5 years later
#9 8 months ago
Quoted from PghPinballRescue:

Solved!!!!
Problem was not with the relay. Jumped the switch contacts and the voltage was still low, and the lights still did not light. I was very optimistic though!
The problem was a the single white wire leading off of the connector in the backbox to the back of the light board. There's a set of 3 ring terminals that screw into the wood on the back of the board.
The input wire was a tiny bit burnt and acting like a resistor. I cut the terminal off, wired a newer gooder one in its place a BINGO BANGO, we're in business!
Thanks to everyone for your input and suggestions.

For what it is worth - I just had the same problem - half the backbox GI in my Freddy was very dim or barely working, and since half - I knew the fuse or relay couldn't be the problem...simply tightened the very loose ring terminal (which was right after the last bright bulb in the string) and back to normal!

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