Medusa trouble shooting

Have a Medusa that I have been working on and is 95% Working.

When a game is started the 7 bank drop targets get reset and drops all but 2.
From what I have seen it should be starting with 1 then reset to 2, then reset to 3 continuing on to 7 targets are up.
The display gives credit for single drop target, so it sees it engaged but contacts on single target are open when drop target is up.
That single drop target (middle one) work in other configurations like 3, 5, 7targets

What am I missing
Looking for other ideas

#2 8 years ago

LEM

5280wzrd

https://pinside.com/pinball/forum/topic/bally-medusa-help-needed

do you have a video of start-up? It could be a bad diode in the matrix. Mine did somthing similar, it was a diode.

#3 8 years ago

BOY

vid1900

Pinside member

Sana'a

12y 164K 40,201 18

What does the switch test and solenoid tests say?

#4 8 years ago

DAD

MrBellMan

Pinside member

Concord, CA

11y 87,150 1,894 4 11

Unfortunately if you search Pinside and RGP, you will see that a few of us have has the "exact same" issue and never found a fix. It's really a head scratcher because everything tests perfect...

Good luck and be sure to post a fix if you find one!

Rob Bell
Robsgameroom.com

#5 8 years ago

LEM

5280wzrd

Does it drop alone or simultaneously with another target?

#6 8 years ago

ANT

teletub

Pinside+ Frequent

Dallas, TX

10y 61,400 42 3

Yes, same exact issue here. I can not seem to figure it out. I have replaced the board (original, to Alltek), switched the solenoid and even the lamp board and the transformer just to make sure. It must be a playfield issue.

#7 8 years ago

BIL

dothedoo

Pinside member

12y 106K 7,265

Someone please post a video.

#8 8 years ago

MAN

Manu2

Pinside member

8y 16,150 37

The coil under the apron needs 2 diodes. And there's only one diode...

Same problem on Medusa serials 1022 & 2092, solved by adding a diode or changing the coil. It seems to be a mess up between coils at Bally, when they've made the pinball. I would be interested to see what are the serials of your Medusa.

#9 8 years ago

DAD

MrBellMan

Pinside member

Concord, CA

11y 87,150 1,894 4 11

Quoted from Manu2:
The coil under the apron needs 2 diodes. And there's only one diode...
Same problem on Medusa serials 1022 & 2092, solved by adding a diode or changing the coil. It seems to be a mess up between coils at Bally, when they've made the pinball. I would be interested to see what are the serials of your Medusa.

This is very interesting to read. All of the research I have done and I have never heard of this fix. I will try this as soon as I can on my buddy's game. Hopefully this is what we are looking for!

Thanks for posting this!

#10 8 years ago

LEM

5280wzrd

I believe that is what I did to fix mine. I do remember for sure it was a diode problem. Just can't remember what coil. Look to see what solenoid if firing at the same time the target drops.

#11 8 years ago

Madmax541

Pinside+ Frequent

You guys nailed it.
Kickout coil only had one diode.
Changed it problem solved.
Why does this bally need two diodes on some of the coils?

Another problem.
Game works fine except for one thing left flipper works for 2 to 4 flips and then stops working and starts working for 2 -4 then stops.

Flippers have been totally rebuilt, cabinet flipper switches are new.
Switches are gapped properly

Any thoughts?

#12 8 years ago

LEM

5280wzrd

OP
Quoted from Madmax541:
You guys nailed it.
Kickout coil only had one diode.
Changed it problem solved.
Why does this bally need two diodes on some of the coils?

Because of the solenoid expander ckt, voltage will back feed and energize multiple coils without the diode in place and working. (As you see with your drop target) Here is a video of proper target operation.

#13 8 years ago

DAD

MrBellMan

Pinside member

Concord, CA

11y 87,150 1,894 4 11

This is really great news! My buddy checked his as well and only one diod. We will fix that ASAP!

#14 8 years ago

Madmax541

Pinside+ Frequent

Could grounding of SDB cause intermittent flipper?
Only left flipper has issue.

#15 8 years ago

BIL

dothedoo

Pinside member

12y 106K 7,265

What's the issue with the flipper?

#16 8 years ago

Madmax541

Pinside+ Frequent

Game works fine except for one thing left flipper works for 2 to 4 flips and then stops working and starts working for 2 -4 then stops.
Flippers have been totally rebuilt, cabinet flipper switches are new.
Switches are gapped properly

#17 8 years ago

BIL

dothedoo

Pinside member

12y 106K 7,265

When it stops working, hold flipper button in and try wiggling connectors on SDB. Are the EOS switches new too?

#18 8 years ago

Madmax541

Pinside+ Frequent

EOS are new
Hold flipper button wiggle wires no change.

How do you test solinode expander board?

#19 8 years ago

Madmax541

Pinside+ Frequent