Hmmm... I used to have a Gtb. Airport once
how about a few photos ?

I'm going to move this into the EM hangout sub forum if you dont mind,
it should make it faster / easier to find by the EM crew we have now

Sounds like a short circuit somewhere caused by broken insulation rubbing against something causing that or two wired terminals touching , bad bulb ,possible short caused by playfield action when hitting a target ,bumper ,rollover,ect. that has a shorted path.

Lets narrow it down.

What circuit is controlled by this fuse ?

Maybe the jones plug is in wrong? causing the weird issues.

Mabe a shorted bell/chime coil or score reel coil?

Check for screws under the Jones plugs. Gets me every time

-Jeff

First thing I thought of. My "Jungle" did that to me.

Best of luck.

Short circuits are hard to find. You have done a great job narrowing it down. I would suggest you narrow it further.

First, you should make one of these, as it will save you time, money and aggravation:
http://www.pinwiki.com/wiki/index.php?title=EM_Repair#Electrical_short_troubleshooting_Fuse_helper

Next, pull out your schematic and look up the 100 relay on the LEFT hand side. It is likely labeled L.

It will probably say something like: 9E L A-9735 AG 6A 100 Point Relay.

9E = location on schematic of the coil
L = shorthand schematic label
A-9735 = coil part number
AG = relay "type"
6A = 5 Normally Open switch stacks. There are 6 things this relay does. You need to find them ALL.

Now, either go back and find all the switch pairs on the schematic or just dive in. I would prefer to find the switch pairs. The following are from a Gottlieb Mini Cycle of the same era.
1. Lock in on the relay
2. Chime
3. To the high score circuitry
4. To the first and second hundreds unit
5. 0-9 match unit
6. To the thousands (K relay)

Now, start eliminating circuits. Maybe slip some paper in between the switches or desolder. Keep going until the circuit breaker no longer breaks.

Now you know what circuit you are on, and your detective work is reduced by a factor of 6.

Good Luck.

Todd
Team EM

Main?
If its the first fuse main then the power cord (cheap to replace) could have an internal short or the wall plug socket is Fubar.

Best bet get a meter w/a beeper type option for continuity and start checking & moving the wires around to see if it triggers ,+ck sockets, +ck 4 bad bulbs too.

Airports a tough game to roll
-good luck with it