Gorf Level Display Lights (Space Rank):

Another little thing that I like about Gorf is the small panel to the right of the screen that has 6 difficulty level indicator lights. The light show your "Space Rank" which is your skill level. The lights are driven by the "display" board. The display board also drives the small lamps inside the top of the joystick and the coin counters. Each time you make it through all 5 games, you are promoted to the next level of difficulty. Each lamp in the display board lights one of the 6 squares labeled Space Cadet, Space Captain, Space Colonel, Space General, Space Warrior, Space Avenger.

Once you get to the Space Avenger level, the game doesn't get any harder. If you are proficient at this level, you can play for as long as you can stand it. If you need to take a break from the action, remember that on game 2 (Laser Attack), if you kill all of the ships except for one of the laser ships, you can then move down into the lower left corner of the screen and the laser ship will never be able to get you. You can go take a break and come back whenever you want and continue your game. You might think of this as a quirk or bug in the game. Since we're now talking about Gorf game bugs, here's another one. One game 1 (Astro Battles), sometimes if you move to the far left of the screen and shoot at nothing and allow the shot to go all the way to the top of the screen, a ship in the top row that is nowhere near your shot will die as if you had hit it. I have killed as many as 3 ships in quick succession doing this. It doesn't always work and I don't know why, but it often does work.

The display board, shown below, accepts six wedge based 12V bulbs. The bulbs are commonly known as models #161 (or #194). To replace the bulbs, the control panel must be removed as well as the metal bar above it and also the glass. Once you gain access to the bulbs, you can remove them from the front, that is if you can get a grip on them. I prefer to reach under and behind the entire assembly and remove the lamp sockets from the rear of the board. The sockets are a simple twist-lock type. Grab the back of them and twist them about 1/8'th of a turn until the contacts line up with notches in the driver board PCB and they'll pop right out.

(click images to enlarge)

Display Board Bulbs and LED Replacements:

When I replaced all of the 110 VAC marquee lamps in my Gorf cabinet with 9W compact fluorsecent bulbs, I was very pleased with the power reduction. The cabinet interior runs a lot cooler inside than it did with the old tungstens lamps. Also, since the new bulbs last so much longer, I rarely have to change them. I also like the color spectrum much better. I think that the colors of the marquees actually look a lot nicer.

I later considered that I could further improve things by replacing the display board light bulbs with modern LED lights. New LED lights use less than 1/25'th (4%) as much power as the old tungsten bulbs. They are available in different colors, are not expensive, and virtually never burn out. Since they require so little power, they place practically no stress on the drive transistors and thereby greatly improve the life expentancy of those transistors.

Here is a typical #161 light bulb (left picture) and the LED light (right picture) that replaces the bulb.

#161 tungsten bulb LED lamp

Both lamps shown together below, LED on left, #161 bulb on right. In these photos, the LED lamp shown is "amber".

The LED lamps that are presented here were purchased online from here: http://www.superbrightleds.com

WLED-W-90: cool white, 90 degree, wedge base, 12V AC/DC, $1.29 each USD

WLED-A-90: amber, 90 degree, wedge base, 12V AC/DC, $0.79 each USD.

Since tungsten light bulbs produce a light spectrum commonly known as warm white which contains a lot of red, I would prefer to use an LED lamp that has approximately the same spectrum. This would be so that the display would visually appear as close as possible to the way it looked originally with the #161 bulbs. However, the LED lamps that I found available did not include warm white so I had to choose between cool white and amber. The superbrightleds website also sells a similar model that has has a 120 degree dispersion angle. I chose the 90 degree model because I wanted the new LED lamps to direct as much light as possible forward into the glass bezel.

Since writing the above, I have discovered another source for #161 bulb replacement LEDs that are similar to those available from the superbrightleds site, however, these include both cool and warm white. Also, they have brighter LED's.
Here: CoinTaker LED #161 Lamp Replacements

To get all six of the lights to stay on at the same time, I made a custom wiring adapter and plugged it in between the game harness and the display board.


To give you a good idea of what the LEDs will look like in your Gorf machine, I have set up the lights shown in the pictures below as follows:

Top row:
cool white LEDs
Middle row:
amber LEDs
Bottom row:
original #161 light bulbs



I decided that I preferred the cool white LEDs the best, so I installed them in all 6 locations as shown below.


And finally, after removing the wiring adapter, here's what it looks like playing a game with the LED lamps.

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Midway, 1981
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Last update: July 5, 2015