Guide To Gottlieb EM Score Reels – Cleaning and Fixing
Prior to starting, please read the introduction and parts needed page.
Understanding the Switches
Note that the open / close state of these switches changes from generation to generation of the reel. The following description is for the 2nd and 3rd (last) generation of the Gottlieb Dragon reel.
Each Gottlieb score reel has several switches, each one crucial to the operation of the pin. Failure of any switch in any reel can prevent the machine from entering game play.
- This tells the game that the reel is reset. If this does not work, the game will never start. The scoring reel in the cabinet will keep spinning. Also called the ‘zero switch‘.
- These switches make contact from 1 – 9. If these do not make contact, the score wheel will not move during the startup sequence. This is sometimes called the ‘runout’ switch.
- This switch makes contact on 9 and tells the pin to carryover the score to the next higher reel. This switch is usually absent on the highest score reel. Also called the ‘nine switch‘ or ‘On Add‘.
- This switch is a EOS (End of Stroke) switch. This makes sure that the solenoid is powered long enough to pull all the way in. When this switch opens, the power is removed from the solenoid and the number advances. If it opens too soon then there is not enough power. Not at all and the solenoid stays energized.
- This is a second ‘nine switch’ or ‘On Add’ switch. In conjunction with #3 switch, this switch is in series and the two are closed together momentarily when the reel advances from 9 – 0. This then advances the next higher reel.
For 1 – 3, each switch has two contacts. These are electrically connected together and are redundant. If either contact works, the pin will work. There are two contacts to increase reliability, so it is important that both be cleaned and make contact.
Switch sequence for 2nd and 3rd generation:
|Switch||Zero||1 – 8||9|
Switch sequence for 1st generation:
|Switch||Zero||1 – 8||9|
Step By Step Instructions For Making a Gottlieb Score Reel As Good As New
[For each image, click on it for a larger picture.]
The first time will be confusing and feel like it takes a long time. Trust me in that doing it a second time will be a lot quicker. After a while, you will be able to do this quickly and easily.
Note: For ease of reassembly and reference positions of parts, it may be helpful to have each score reel set to zero prior to disassemble.
2) Remove the ‘C’ retaining ring and place it in your parts storage bin. If using muffin tins, number the holes (with a pencil!) and place this in the first hole. Move from hole to hole as you remove parts.
3) Loosen and remove the two screws holding the circuit board in position – while holding the other end in place. When these two screws and retaining ring are removed, all sorts of parts and springs can pop off and become airborne.
4) Carefully lift up the circuit board while holding onto the parts located on the numbered reel. There will be a metal electrical contact, a plastic piece, the reel and a spring all waiting to fly out into your room.
This next step in important: Note the position of the metal contact. The single contact will be pointing to between the ‘5’ and ‘4’ on the reel. The backside points to between ‘0’ and ‘9’. When reassembling, it must be put back to that position [see photos].
5) Remove that plastic ring and metal contact and place it into your parts holder while holding the rest of the spring loaded parts in place. Underneath the metal contact is another plastic piece that must be carefully removed, while holding the number wheel in place.
6) Remove the numbered score reel and store it off to the side.
When removing the reel, this plastic part with gear teeth will be pushed out by the spring that is underneath. Prior to removing this, it is important to study its operation for reassembly.
7) Push the circular plastic part with gear teeth back down so that it engages the teeth of the slider part underneath. Now push the plunger into the solenoid and pull it back out. The left most gear tooth will fit into the left end of the slider [see photo]. The teeth on the wheel must line up so that they meet through the entire movement of the slider. If the circular plastic piece is positioned improperly, the teeth will ‘run out’ either when the plunger is pulled in or pushed out. Note how to align the teeth between these two plastic pieces for reassembly!
Now remove the plastic wheel and the spring underneath and place it aside.
8) Next we will be removing the parts attached to the plunger. First remove the bottom spring on the bottom of the slider mechanism. It is important to keep track of where each spring goes.
9) [This step is optional. Some people leave this in place.] Note the wire lever above and carefully note its position in the 3 leaf switch. These are switches 1, 2 & 3 noted at the beginning of this page. When reassembling, this wire must be positioned exactly between those leafs. Now, disconnect the spring holding onto the wire lever above. Remove the wire and spring and place aside.
10) We want to move the EOS switch, #4 and #5 (above) to get it out of the way. Some like to remove one screw and swing it up out of the way. I like to remove it completely – however, if all the screws are removed at once, the switch can literally fall apart.
Loosen both screws and then remove one. Swing it up all the way and then reinsert the screw and lightly tighten the nut. The do the same to the other screw and nut. Finally, tighten the screws and nuts down so they don’t fall off. Alternatively, the switch can be wrapped with a rubber band to keep it together.
11) We are almost done with disassembly. Now remove the four screws holding the solenoid bracket in place. The remaining components will come loose.
If the coil sleeve is stuck in place, use a small screwdriver to free it. If not, it might break during this step.
12) The next set is awkward: Tilt the bracket and solenoid coil up and back while working the slider attached to the plunger. The bracket will have to be tilted about 45 degrees.
It is possible to remove all of this without having to unsolder the wires. Take note as to how you do this step because it will be doubly difficult to repeat it going back together.
Note that as the plunger comes free, there is a ‘U’ shaped guide where it connects to the slider. During reassembly, this guide has to oriented upright to receive the slider. It takes sharp eyes to see this guide.
13) Remove the slider and its spring to expose the base. Also remove the plunger from the coil and set aside.
You have finally completed disassembly and are ready for cleaning, then reassembly.
15) Also wipe around the coil for dirt as any remaining can gunk up an otherwise clean mechanism.
16) Take a look at the plate where the components move back and forth. This has to be smooth and clean in order for the reel to work smoothly.
Take a microfiber cloth and clean the surface with alcohol. Look for any groove or gouge marks. These need to be removed completely. Then bring out your Dremel and the 1/8″ carbon brush and/or sanding disk (see parts list) and shine this surface.
17) When completed, the surface of the plate should be free of gouges and anything else that might cause the mechanism to drag across it. Clean that up with a microfiber cloth. Then, using small amounts of Mothers Mac & Aluminum Polish (see parts required), clean until no more blackened oxidation is removed. Then wipe clean with 91% isopropyl alcohol.
18) Use alcohol and clean off the edges of the slider mechanism. Take out the polishing or sanding wheel for the Dremel and shine up the edges of the slider mechanism that connects to the plunger. The edges of this get worn and this causes a drag as it moves back and forth – we want it nice and smooth. Use a q-tip to clean the plastic ‘gear’ teeth also.
19) Grab the bracket and buff that up also, in the area where the slider and bracket meet. This must be smoothed so that the slider will move freely.
20) When reassembled, the slider will move along two guides (see photo – one is hidden from view). Take the dremel carbon brush and clean any metal ‘burrs’ that might prevent the slider from moving freely. Clean with alcohol.
21) Grab the plunger and clean it up by wiping with isopropyl alcohol. If there are any rough edges, remove those off with the polishing wheel on the Dremel. The edges can be removed with a file, or a dremel sanding wheel, polishing wheel, or the 1/8″ carbon brush.
22) If the switch contacts are tungsten (gray metal and pitted), take back out the 1/8″ carbon brush and clean them. If the switch contacts are copper colored and not pitted, then clean them with a q-tip and 91% isopropyl alcohol. Be sure to clean the EOS switch also.
23) Grab the numbered scoring reel and clean it. It is possible to carefully clean the numbers with a gentle cloth and water with, perhaps, a small amount of detergent. But be careful as in a lot of cases, the numbers will rub right off.
But more important is to use a q-tip soaked in isopropyl and a cloth and clean every nook and cranny in that wheel. Any remaining dirt or goop will prevent prevent the wheel from locking into position.
24) Use the Mothers Mac & Aluminum Polish and clean the circuit board until it shines. Clean until no more blackened oxidation is removed. Then wipe clean with 91% isopropyl alcohol. Use plenty of alcohol to remove all of the polish.
It is only necessary to shine up the area where the contact is being made.
25) Clean the metal electrical contact that rotate around the circuit board. Depending on their condition, they can be cleaned with 91% isopropyl alcohol and/or the 1/8″ dremel carbon brush (gently!).
26) Grab the Teflon lubricant and a Q-tip and lubricate the circuit board (lightly – 1 drop on the q-tip might be sufficient) and the metal area just shined on the bracket surface. Wipe off the excess on the circuit board with a microfiber cloth. If too heavy, the electrical conductivity might be poor.
Do not get any lubrication on the switch contacts.
27) Next, lubricate the sliding surface on the bracket polished up above in step ’17)’. Use the Finish Line Dry Teflon lubricant (or equivalent). Do not use oil of any type.
Just like this did not want to come apart easily, it tends not to want to go together easily. This takes practice and a bit of trial and error to get it all to come together.
28) Grab the coil sleeve and insert it into the coil. The ‘collar’ side goes towards the coil stop. Then take the slider and hold it in position. You may find that now is a good time to install the spring on the slider to hold it into place. Place the coil bracket over the coil.
29) Grab the plunger and put it all together. Note that the ‘U’ – shaped guide has to be positioned with the open end up. Be sure to insert the plunger through the coil bracket. Be patient. This looks easy in photos, but it will take some contortions to get it all back together. In time, this will become a simple step.
Be careful not to force the parts together as this can warp the slider.
30) Screw the coil bracket into place.
31) If you removed the wire lever in step 9), reinstall it and its spring exactly like shown. If the wire is in-between the wrong switch contacts, the pin will not work properly.
32) Be sure to put back the EOS switch near the plunger back into position as shown in the photo. This was moved out of the way in step 10).
33) Inspect this part – the Reel Basket Backwards Latch. This is responsible for not allowing the score reel to turn backwards. The top part should be flat and not bent inwards. If necessary, use a switch adjustment tool to level it out.
34) Install the spring on the scoring reel shaft as shown.
Make certain that all the remaining parts are within reach for the following steps as you will have one hand holding the parts in the reel while the other is grabbing and installing parts.
35) Refer to step 7) above and find that round plastic part with the gear teeth. Insert it over the spring from step 31) and press down until it engages the slider. Insure as you did prior to step 7) that as the solenoid pulls in, then returns out that the teeth of this part engage the slider throughout the entire run.
36) While holding the plastic part in proper place, insert the score wheel (numbered wheel) on the gear part installed in step 32). It is crucial to keep the gear from hoping out of its position. It does not matter what number is displayed on the score wheel. Hold the wheel in place to keep the spring from pushing it out.
37) Insert the metal contacts and final plastic part removed in step 5). Note that the wide end of the metal contact has to point to between zero and 9. If this part is not inserted properly, then various features on the game will not work properly. Be certain to hold all the parts in place and not let the spring push out. Note that some score reels will not have this contact.
38) If this score reel has a circuit board, swing it into place over the score reel while holding all parts in place.
Almost done. Now to check proper operation of the switches.
40) Refer to ‘Understanding the Switches’ at the beginning of this page. Insure that switches 1), 2), 3) open and close as the score wheel turns. Advance the score wheel by manually pulling in the plunger. While advancing the reel, insure that the Reel Basket Backwards Latch engages to prevent the reel from turning backwards. Inspect switches 4) and 5). Insure that the EOS switch stays closed and opens as the plunger pulls in fully.
Comments, including suggestions, improvements, errors, etc. are welcome (see below).
If you have a specific question about your game that does not directly apply to this page, please see our FAQ section.