Cosmic Princess, help diagnosing issues..

[Sinbad79]

Hi guys
I have a problem with a cosmic princess, every time the ball rolls under the left gate, the right slingshot fires. Any ideas on how to diagnose this fault?
Thanks

[Steevsee]

Maybe check that the diodes on the affected switches are connected and working properly.

[Ballywannabe]

Have all the targets up, ball out, put the machine in switch test mode (button inside front door).  Should show ''0'' (no switches closed)

Close switches one at a time and make sure the correct number comes up (refer to manual).

One odd one can be a dud diode, if lots are showing the wrong numbers it is most likely the signals from the MPU (bottom left connector) to the SDB (small middle right hand connector)

Report back your findings

[Sinbad79]

Replaced the diode on the faulty switch but to no avail.
No open switches either.
Could it be a faulty transistor?

[Ballywannabe]

No transistors involved...when you are in switch test mode, and you close the left gate switch, does the correct number show, or the number for the right slingshot?

[Sinbad79]

Left gate correct at switch 05
Right slingshot correct at switch 13

[ralph67]

I had this exact same problem on a CP that i had , follow the common wire from the switch, which i think was blue/white, Check all switches with this wire colour, Just make sure every switch operates as it should and check the gaps, give each a clean with a piece of card,    If this does not solve the prob. Try cutting the cap on the slingshot swt. and retest game. But i would replace the cap with a new one afterwards.

[Sinbad79]

Ralph, you didn't sell this game to someone in Adelaide recently by any chance?

Ok I'll look into your recomemdation.

Thanks.

[Strangeways]

I don't have the schematic, but if the two switches are in the same row or column, replace all the capacitors on switches. I think the above comments are right - it should be the cap across that slingshot.

[Sinbad79]

Thanks guys.
Nino do you know what value caps they are generally?

[Sinbad79]

Just found this:
Source: http://www.pinwiki.com/wiki/index.php?title=Bally/Stern#The_Importance_of_Diodes_and_Capacitors_on_Switches

____________________
4.10.9 Switch Capacitor Purpose and FailureCapacitors are used on switches that are normally subjected to very quick hits, to lengthen the switch pulse that the MPU reads. Not all switches will have capacitors; standups, pop bumpers, slings, and tilt mechanisms are the usual ones that benefit from them. All switches that need a quick reaction can have switch capacitors added to them (such as rollover buttons). These are ceramic non-polarized capacitors of a value of .047 or .050 uf and 16 volts or greater. A commonly available cap is the .047 uf 50 volt through Mouser P/N 140-50U5-473M-RC.

The factory installed caps are often damaged by the high wattage industrial soldering irons used in manufacturing the games, or they succumb to the vibration over time and no longer serve their purpose of lengthening the switch closures so the MPU can read them. Often a repairman will clip the cap off to diagnose a stuck switch problem and not bother to replace it. The switch will operate in this fashion, but for more sensitive play, the capacitor should be replaced. A failing cap can also make a switch bounce, and cause machine-gunning of a slingshot or pop bumper.

[Sinbad79]

Ok well diodes and caps changed for switches concerned, but to no avail.
There is obviously something else at fault.
Any more ideas?

[ralph67]

Ralph, you didn't sell this game to someone in Adelaide recently by any chance?

Ok I'll look into your recomemdation.

Thanks.No i bought Studley's Cheetah from SA . The other CP is at a mates place . I do have a project on here though and will double check the wire colours for you. These are daisy changed so  follow it along , check each and give the switch stack a wipe also not just the contacts.  Down the sides etc. I think this was fixed mine!

A build up of dust etc could cause a false closure and causes sling to fire , And double check no dampening blades are not touching the wrong blade . i you know what i mean.   The Capacitors. when i replaced one on the offending switches it worked for a while . But it would only last a short time before playing up again.

[Sinbad79]

Yea definitely not that.
Perhaps an electrical short?

[Strangeways]

Do you have a spare Solenoid Driver board to swap out ?

I did have a similar issue on a Galaxy years ago and it was the 3081 Chip at fault. Would take 10 minutes to isolate the problem. This is no obvious solution - Yet !