Medusa
Bally, 1981I was diverted to a really long “honey do” list yesterday.
The drops are now working. It was just too tight behind the drops for some to release. I realigned the whole mechanism and sanded the openings lightly - a lot of clear coat drip - and all appears to be good.
I will report back after a few more honey dos today. Sleeping beauty is currently asleep so some quiet time this morning to work on the pin.
Darn this thing!
I finally felt like it was time to move the pf back to the top brackets in the cabinet so I could play the first game. Now a few additional problems have developed.
The rear drops now set properly in game and when the pin is initially powered on, but do not all reset as they should in game
Game starts with center target up , it drops and the other correct targets raise, I drop those targets and no additional targets are set.
Right four drops do not reset in game, but do reset when pin is turned on.
The following switches are not registering - 48, 44, 36, 20, 12, 4.
So close and yet so far.
Robert
Quoted from StratDoc:The rear drops now set properly in game and when the pin is initially powered on, but do not all reset as they should in game
Game starts with center target up , it drops and the other correct targets raise, I drop those targets and no additional targets are set.
Right four drops do not reset in game, but do reset when pin is turned on.
Your solenoid issues are likely due to switches not registering.
Quoted from StratDoc:The following switches are not registering - 48, 44, 36, 20, 12, 4.
Switches 44, 36, 20, 12, and 4 are all on the same row in the switch matrix. This row also has switch 28 but you didn't mention that it's not working. What's the story with switch 28?
Have you made sure there's continuity on that switch row signal back to the MPU board?
A few posts ago you mentioned switch 48 and 46 not working. Is switch 46 working now?
Is switch 48 making proper contact when closed?
Switches are now all registering. Left four bank drop is working fine. Drops across the top all register but do not reset after second sequence - first sequence center target up, second sequence two targets up - after completing the second sequence additional drops do not raise.
Quoted from StratDoc:Switches are now all registering.
When you fix things, can you tell us what the problem was so we can understand where the source of the issues were?
Quoted from StratDoc:Drops across the top all register but do not reset after second sequence - first sequence center target up, second sequence two targets up
This sounds suspiciously like you've still got switch issues with those top drop targets. If they're not resetting after you hit the round two sequence, one of those drop switches probably isn't registering properly.
When it happens in game, lift each of the top targets one by one and drop them back down to see if the game scores/registers them.
I finally got the drops to work by adjusting switches.
I played one game - 
but then I started getting scoring issues. A single player game starts with both the first and the second player lit with a score of 0,000,005 on each display. As I play score randomly increase or decrease on both displays. Once the ball drains scores keep decreasing.
I will try to take a closer look in the morning and post back.
So the display problem is related to the coin door. With the door open everything works fine, and I can play a game. With the coin door shut the first and second player displays post 000,005 and you cannot reliably start a game. Sometimes I can get it to start but game play results in the very odd scoring mentioned above on both first and second player displays.
Check what happens when you close the coin door. The most common problem is the start button shorting with the ground, on the door.
Make sure that the switch is fully insulated from the press button. Also, the switch blades may be touching some metal parts of the lock bar system.
Raise the playfield, close the door and check carefully what is going on.
Yves
Thanks, Arcane. I checked the start button and it okay - insulated and not shorting to ground. I isolated the problem to the left side of the coin door but cannot see what is shorting. It is not the lock bar because the problem exits with it removed. If a raise the pf slightly the problem goes away. As a temp fix, I took a very thin sheet of plastic and laid it across the top of the left side of the coin door and coin slot mechanism.
On a positive note - with that issue temp fixed the pin works!!! Played my first couple of games and will post up a video today!
Quoted from StratDoc:Quench,
Here it is thanks to your patience and help! This was a bear. thank you for sticking in there with me. Learned a ton!!!
You are the greatest. It looks great sitting next to the Paragon.
Yeah Quench great of you to continue to help out here. Most people would've bailed. Learning along side the OP on this one in the even I ever have issues on my Medusa!
StratDoc..... just a tip... turn your phone sideways when you take video 
Congratulations to both you and Quench! Great combination - your perseverance and Quench's knowledge and patience. I recently acquired a Medusa with a few issues so this thread has been very interesting to me. I'm sure I will be returning to it at sometime in the future as it contains a ton of good information.
Great game to play. Challenge Medusa!
May have spoke too soon. After a few games switch 18 has decided to show closed even though the actual switch is gapped appropriately. Double checked wiring and it is okay.
In game. switch 18 does not register and activating either flipper causes 10 points to score with same sound as you would get when 18 is activated.
Darn thing was playing great for about 20 games.
It is definitely a switch matrix issue and not vibration. Holding the flippers up and pressing the flipper switch activates the 10 point score and sound.
I also have continuity from the mpu connector to both #18 switches.
Quoted from StratDoc:It is definitely a switch matrix issue and not vibration. Holding the flippers up and pressing the flipper switch activates the 10 point score and sound.
The flipper switches are not part of the switch matrix. What happens when you bang the playfield with your fist?
.
Quoted from StratDoc:I also have continuity from the mpu connector to both #18 switches.
There's three #18 (10 point) switches, not two. Check the third one.
Medusa_10PointSwitches.jpg
Continuity to the third one as well.
Banging on the pf does cause 10 points to register on occasion. However holding flippers up so there is no vibration and closing flipper switch also causes 10 points to register. Switch 18 will not register at all in game. Shows closed in diagnostics. Darn this pin.
SOLVED. I am an idiot. It was the top right switch 18 that was causing the problem.
On another note, I removed most of the capacitors on the switches. Good I idea to replace them or just leave off?
Quoted from StratDoc:It was the top right switch 18 that was causing the problem.
Cool.
Quoted from StratDoc:On another note, I removed most of the capacitors on the switches. Good I idea to replace them or just leave off?
To be honest, I would replace the capacitors - when you have fast hits on standup targets and they're not recognised, that can get annoying.
One smaller problem is the zipper flipper mechanism. The plastic catch will not stayed hooked on the metal tab attached to the solenoid. A couple of zipper flipper strokes and it jiggles loose. I am guessing it is worn. I could not see a way to adjust the tension so that it is tighter.
The right lane to the top of the playfield registers only on occasion. I have gapped the switches several times but still have not resolved the issue.
Quoted from StratDoc:The right lane to the top of the playfield registers only on occasion. I have gapped the switches several times but still have not resolved the issue.
Have you cleaned the switch contacts?
.
Quoted from StratDoc:One smaller problem is the zipper flipper mechanism. The plastic catch will not stayed hooked on the metal tab attached to the solenoid.
I don't know if these pictures help.
Maybe you're missing the spring on the back of the metal tab that latches the plastic hook.
Zippers mechanism latch open
Zippers mechanism latch touching
Zippers mechanism closed
Zippers mechanism metal latch spring
This pin is killing me. The drops have decided not to reset at power on it in game. The solenoid expander board is not engaging and no power to the drop coils. I am thinking a connector issue - still waiting on connectors so I can repin the whole thing. Any other things to check? It was playing fine, started another game and no drops and the two top left pf lights and the left and right center lamps behind the green targets are dim.
Quoted from StratDoc:no power to the drop coils
Do other coils have 43V solenoid power? If yes, your daisy chained 43V solenoid power (yellow wire) might have lost connection somewhere on the playfield at one of the coils.
I found the bad connection on the pf. Posting out of frustration more than anything. The darn pf is so crowded anytime I raise it to fix an issue or make an adjustment I seem to create another problem by bumping stuff around. The cabinet design for raising the pf is a challenge as well having to lift it to the second set of posts to get better pf access. I really like the Gottlieb design that exposes the whole pf.
You've had a few bad coil connections now - you might want to check that they're all solid by pulling on them - resolder any that look flaky.
Quoted from StratDoc:The cabinet design for raising the pf is a challenge as well having to lift it to the second set of posts to get better pf access. I really like the Gottlieb design that exposes the whole pf.
Agreed it's a pain. The wood rails the playfield sat on and was maneuverable upright on the previous Ballys was much better.
Quoted from StratDoc:The dim lights are strange. Power to the lights is okay. Two top left and the two behind the green targets. Hard to get to.
As usual, ground the colored control wire at the lamp socket. If the lamp stays dim, it's the socket or lamp. If the lamp goes bright it's likely a bad connection back to the lamp board on the colored control wire.
Quoted from StratDoc:I think these are general illumination lamps. An orange wire and a green wire daisy chainedto other lamps.
Make sure you measure 6.5V - 7.0V AC across the two lamp socket connections - don't use ground as a reference. After that change the lamps and/or sockets as necessary.
Ok, this time put the black meter lead on a ground point and measure both pins at the lamp sockets with the meter still set on AC voltage. What voltage do you get on each colored wire at the lamp sockets?
Quoted from StratDoc:2.3 volts AC on orange 0 volts on green. Ground short or poor connection somewhere along the daisy chained affected lamps?
Well, the daisy chain usually starts at the rear of the playfield. Find other GI lamps with orange and green wires and check continuity on the orange wire.
That orange wire comes from the rectifier board at J1 pin 1. Check continuity from the orange wire at a dim lamp to that pin on the rectifier board, and then further upstream past the J1 connector at test point TP1 on the rectifier board.
Not all GI are out just those mentioned. Aren’t they all on the same chain from the rectifier board?
The lights affected have continuity between them. I lose continuity between known working GIs and the affected lamps. No continuity between j1 pin 1 and the affected lamps.
Quoted from StratDoc:Not all GI are out just those mentioned. Aren’t they all on the same chain from the rectifier board?
No. There's two sets of GI lamp wires from the rectifier board to the playfield. You have the orange and green set, and then the red and white set. Red and orange are connected together back at the rectifier board. Green and white are connected together back at the rectifier board and these are also ground.
Note, the schematic below lists the orange wire going to the zipper flippers EOS switch stack to power the lamps under the main lower red flippers. Check there for a bad connection.
That was exactly the problem. One of the orange wires at the EOS for the zipper flippers was coming loose. I need to recheck all of my soldering on this thing. As you pointed out, that seems to be a recurrent problem.
Everything has been working great for the past couple of weeks except I am still having issues with the "shoot again" lamp.
The lamp will not light in lamp test diagnostics or in game. Here is what I have diagnosed thus far.
1] there is continuity from J3 pin 22 to the lamp
2] grounding the blue/yellow wire at the socket turns on the lamp
3]grounding at the connector J3 pin 22 turns on the lamp
4] grounding the transistor q40 turns on the lamp
Quoted from StratDoc:4] grounding the transistor q40 turns on the lamp
Grounding the anode leg/tab of the SCR doesn't actually test the SCR. It just tells you whether you have good continuity from the SCR to the respective lamp.
To test the SCR, you need to run a jumper from test point TP3 on the lamp driver board to the left "gate" leg of SCR Q40.
Actually it was previously determined that Q40 was faulty. How did you repair it? Didn't you mention you piggy backed a new SCR on top of the faulty one? Can you post some clear pictures?
BTW, the lamp board doesn't have "transistors" - they are "Silicon Controlled Rectifiers" (SCRs) also known as Thyristors. They may look like transistors, but SCRs have a different function 
Oh good, you removed the faulty onboard SCR.
Ok, the reason it's not working is because the replacement SCR is on backwards. You need to flip it around so that the metal tab faces outwards 
The question is whether that replacement SCR is now damaged.
This is how I test SCRs with a multimeter:
Set your multimeter to diode mode.
With the particular replacement SCR you're using (MCR106 or C106) test all combinations of the meter leads on all three SCR legs, including swapping the meter leads around.
With the metal tab on the backside, you should only get a diode type reading with the black meter lead on the left SCR leg and the red meter lead on the right leg.
Now.. put the black meter lead on the left leg and the red meter lead on the middle leg. You should get no reading. Carefully slide the red meter probe on the middle leg so it bridges across to the right leg and shorts the two legs, then slide it back so it's only touching the middle leg. The meter should now show a diode reading between the left and middle leg.
I hope this makes sense.
That did it. Flipped the SCR around and now works fine. I had no idea it was on backwards 
All is working well with the exception of the occasional rear drop that doesn't want to reset. Those drops are really finicky. I have to adjust the same one - third from left - frequently.
Quoted from StratDoc:All is working well with the exception of the occasional rear drop that doesn't want to reset.
Is this an electrical/electronic issue or mechanical?
Quoted from StratDoc:All is working well with the exception of the occasional rear drop that doesn't want to reset.
Is the issue that drop target #3 from the left sometimes doesn't respond (switch not recognised/no score) when it's knocked down, or that it's recognised but after the whole bank is reset, drop target #3 doesn't drop when its individual coil activates to drop it?
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Chattanooga, TN