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Classic Stern multiple switches firing at once


robm

Question

Have an issue with Stern Quicksilver, if i drop the middle right drop target, it accumulates points continuously until the 3 bank of targets resets.

 

Put the machine in switch test, and when i hit the middle right drop target switch (31), switch 23 also appears on the displays (which is one of the drops on the left bank of targets). They both share a brown yellow wire. I tested the diodes (in circuit on both sw 31 and sw 23, and both test good - and the same as the other diodes nearby. When i test sw 23 by itself in switch test, it only fires itself.

 

I also noticed that standup target sw 15 in swtich test also fires sw 7 (tilt) - but it doesn't tilt during a game. Interestingly, sw 15 also has a brown/yellow wire.

 

Any suggestions on where to from here - should i replace the diode on 31 even though it tests OK?

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Have an issue with Stern Quicksilver, if i drop the middle right drop target, it accumulates points continuously until the 3 bank of targets resets.

 

Put the machine in switch test, and when i hit the middle right drop target switch (31), switch 23 also appears on the displays (which is one of the drops on the left bank of targets). They both share a brown yellow wire. I tested the diodes (in circuit on both sw 31 and sw 23, and both test good - and the same as the other diodes nearby. When i test sw 23 by itself in switch test, it only fires itself.

 

I also noticed that standup target sw 15 in swtich test also fires sw 7 (tilt) - but it doesn't tilt during a game. Interestingly, sw 15 also has a brown/yellow wire.

 

Any suggestions on where to from here - should i replace the diode on 31 even though it tests OK?

 

Wow. The exact same issue on meteor.

Same switch (31) the 1st e target on meteor sets off 23... And scores points forget until it resets.

Funny things is that it also set off 7 sometimes. But no tilt.

 

Also... Don't think I had this issue before I fixed the other issue of the sling nor being wired properly.

 

Also! I Chnaged the dioxide on switch 31...did nothing

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Further info - i went into switch test then removed plugs J2 and J3, when jumping the appropriate row/column pins on J2, the problem disappeared - ie: confirming that it is a wiring/playfield issue, not an MPU issue.
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J2 on the MPU is for strobes and returns for the playfield.

J3 is for the cabinet.

A diode can test okay but under load can fail.

You say you have confirmed it is switch related on the playfield.

If it was all fine and just happened out of the blue then it sounds like a switch diode/s.

Have you tried swapping/reseating U10 and U11?

Also reseating all chips on the MPU?

Should you be heading down the switch diode way, I personally find it easier to change them with the playfield out of the machine.

This way you could change them all.

But, with the playfield out you can use a multi meter on diode test and check every switch individually.

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J2 on the MPU is for strobes and returns for the playfield.

J3 is for the cabinet.

A diode can test okay but under load can fail.

You say you have confirmed it is switch related on the playfield...

But, with the playfield out you can use a multi meter on diode test and check every switch individually.

 

Is unplugging J2 and J3 the same as taking out the playfield, ie u can then test all the diodes in circuit?

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Replaced diodes on all switches in the brown/yellow row under the playfield - no result. I didn't bother doing diodes in the cabinet switches (tilts), as i disconnected J3 which are those wires and the problem remains.

 

Also removed the brown/yellow wire from each under playfield switch one by one and the switch test still gives multiple hits of different switches each time (was trying to isolate it to a single switch).

 

Have inspected all those switches (7,15,23,31,39) with the brown/yellow wire that are firing multiple times when one is pressed, and can see no metal parts above or below the playfield around them! Starting to go nuts with this one as i don't know what to try next.

 

Am i heading down the wrong track just looking at the brown/yellow wire which is for row 7 - do i need to trace the corresponding column wires for each switch in that row?

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Further update. Even though i thought it was not MPU related (due to pulling J2 and jumping pins and it testing fine), i put in an Altek board from my Paragon, and it works fine!!!

 

So now an assuming its an MPU issue - i guess i will looking at J2 where the brown/yellow wire goes, but not really sure what i am looking for!

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You may want to read right through this section...

 

Yes you have an early Stern and this is about Bally switch matrix but an early Stern is merely a cheap Bally copy.

 

With this information you should be able to precisely diagnose your problem.

 

A couple of switch matrix problems many over look it that caused by diode failures on the dip switch banks and the credit button insulation. Coin switches jammed on are also one you only find though experience as well.

 

http://techniek.flipperwinkel.nl/ballyss/rep/index3.htm#smatrix

 

Good luck.

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You may want to read right through this section...

 

Yes you have an early Stern and this is about Bally switch matrix but an early Stern is merely a cheap Bally copy.

 

With this information you should be able to precisely diagnose your problem.

 

A couple of switch matrix problems many over look it that caused by diode failures on the dip switch banks and the credit button insulation. Coin switches jammed on are also one you only find though experience as well.

 

http://techniek.flipperwinkel.nl/ballyss/rep/index3.htm#smatrix

 

Good luck.

 

Saying that Stern is merely a cheap Bally copy is only an opinion, not fact and not relevant.

 

- - - Updated - - -

 

Further update. Even though i thought it was not MPU related (due to pulling J2 and jumping pins and it testing fine), i put in an Altek board from my Paragon, and it works fine!!!

 

So now an assuming its an MPU issue - i guess i will looking at J2 where the brown/yellow wire goes, but not really sure what i am looking for!

 

Hang in there, you will sort it out.

If you have replaced the mpu and the problem/s has/have gone you are on the way.

 

- - - Updated - - -

 

Is unplugging J2 and J3 the same as taking out the playfield, ie u can then test all the diodes in circuit?

 

Just to be correct, removing 2 plugs from the MPU is not the same as removing the playfield, but yes you can isolate the switch matrix circuits.

I only put this because there are people who will split hairs to ruin a thread/post.

If you want to test the playfield switches then they are solely related to J2 on the MPU

If you want to test the cabinet and door switches they are solely related to J3 on the MPU

There are other diodes in the machine that are not related to the switch matrix.

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i would have said the fact classic stern is a cheap copy of bally, so bally help guides are therefore useful; was a given not an opinion and extremely relevant.

 

is the little filter cap for that return shorting under load rob? ( c20 by the looks) lift one end and see. wondering if you're seeing a ground short not a switch trigger and its getting confused?

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Saying that Stern is merely a cheap Bally copy is only an opinion, not fact and not relevant.

 

 

As a forum is all about learning, I put this out as proof what I wrote is indeed fact, not an opinion.

 

Quote from PinWiki...

 

Bally first started to experiment with solid state in the mid 70s with a couple conversions of EM games, Flicker and Bow & Arrow. Flicker's control system was designed by Jeff Frederiksen of Dave Nutting Associates, a Bally think-tank. This board utilized the Intel 4004 microprocessor. One prototype was built and was re-discovered in 1998. The Bow & Arrow system of which 17 were eventually built more closely resembles what actually ended up in the production games starting with Freedom. This boardset was designed by a Bally engineer named Doug MacDonald. There are at least two revisions of the prototype run's software in existence.

The early circuit boards were fabricated by a company called Universal Research Laboratories (URL). URL was purchased by Gary Stern as part of his strategy in acquiring the assets of the defunct Chicago Coin; it is this connection that enabled Stern to use essentially the same hardware for their solid state games as Bally. The software is remarkably similar as well, although Bally was more apt to use a "set" of operating system roms (the U6 chip) for several games, whereas Stern opted to custom-compile their roms for each game, or at most, pairs of games.

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i would have said the fact classic stern is a cheap copy of bally, so bally help guides are therefore useful; was a given not an opinion and extremely relevant.

 

is the little filter cap for that return shorting under load rob? ( c20 by the looks) lift one end and see. wondering if you're seeing a ground short not a switch trigger and its getting confused?

R53 links to the pin where the suspect brown yellow wire goes. This then is linked to c25. Are you suggesting lift one end of it and see if the game works OK? Or will this stop any switches in that row from working?

 

Swapped u10 with u11 and no difference.

 

Sent from my ALP-L29 using Tapatalk

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As a forum is all about learning, I put this out as proof what I wrote is indeed fact, not an opinion.

 

Quote from PinWiki...

 

Bally first started to experiment with solid state in the mid 70s with a couple conversions of EM games, Flicker and Bow & Arrow. Flicker's control system was designed by Jeff Frederiksen of Dave Nutting Associates, a Bally think-tank. This board utilized the Intel 4004 microprocessor. One prototype was built and was re-discovered in 1998. The Bow & Arrow system of which 17 were eventually built more closely resembles what actually ended up in the production games starting with Freedom. This boardset was designed by a Bally engineer named Doug MacDonald. There are at least two revisions of the prototype run's software in existence.

The early circuit boards were fabricated by a company called Universal Research Laboratories (URL). URL was purchased by Gary Stern as part of his strategy in acquiring the assets of the defunct Chicago Coin; it is this connection that enabled Stern to use essentially the same hardware for their solid state games as Bally. The software is remarkably similar as well, although Bally was more apt to use a "set" of operating system roms (the U6 chip) for several games, whereas Stern opted to custom-compile their roms for each game, or at most, pairs of games.

 

yeh waaay off topic to the thread, not unusual, but you have quoted pinwiki that doesn't mention at all the word cheap copy, I'm confused why you even bothered posting and please explain how it's relevant to a member's pinball switch problem. Maybe by a PM so as to not screw up this thread any more.

Maybe if have proof from your wide and varied experience with these boards as to why they are a cheap copy you might enlighten the readers?

Oh and you too doug, the relevance factor of a Stern versus Bally MPU being related to a switch problem?

The copper plating thickness on the boards are equal as is the quality and labeling of screen printing, if there ever was an inferior copy of an MPU of that era it was ASTRO, also irrelevant.

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yes rob lift the top where you're pointing is what i was thinking.. or just change it

 

- - - Updated - - -

 

the relevance factor of a Stern versus Bally MPU being related to a switch problem?.

 

if the fact the schematic is indentical and the boards are interchangabe isnt enough for you to consider the original bally board troubleshooting resources to be relevant im not interested in debating it further sorry

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yes rob lift the top where you're pointing is what i was thinking.. or just change it

 

 

 

Thank you good sir. Lifted one end of C25 and the game now plays fine - ie: drop the drop target (sw 31) and it doesn't rack up points. However, in the switch test, when i hit sw 15 (stand up target), it also triggers sw 7 (tilt) - however it no longer tilts the game during gameplay.

 

So do i replace this cap (haven't got the schematic in front of me, anyone know the size off the top of thier head?), or do further investigation?

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Thank you good sir. Lifted one end of C25 and the game now plays fine - ie: drop the drop target (sw 31) and it doesn't rack up points. However, in the switch test, when i hit sw 15 (stand up target), it also triggers sw 7 (tilt) - however it no longer tilts the game during gameplay.

 

So do i replace this cap (haven't got the schematic in front of me, anyone know the size off the top of thier head?), or do further investigation?

 

yessir swap him out.. 390pF according to the playboy manual .. i cant find an mpu100 schematic but it will be the same or close enough

 

- - - Updated - - -

 

top right corner rob - https://www.ipdb.org/files/1570/Stern_1978_Memory_Lane_M_100_MPU_Schematic_High_Resolution.pdf

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yessir swap him out.. 390pF according to the playboy manual .. i cant find an mpu100 schematic but it will be the same or close enough

 

- - - Updated - - -

 

top right corner rob - https://www.ipdb.org/files/1570/Stern_1978_Memory_Lane_M_100_MPU_Schematic_High_Resolution.pdf

 

 

OK, had a 470pf cap here (not a 390pf), and used it - back to the same problem. So i lifted one end again, and problem gone. Is this a function of the cap being the wrong size (i wouldn't have thought so?), or something else?

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Got it sorted! Thanks for all the help. Replaced r40 which tested different to the others in that group. It's a 56k resistor and all is good now in time for my Christmas comp in a week and a bit! 2fa26e3e7e7a7e84bb297c6d89d9fd83.jpg

 

Sent from my ALP-L29 using Tapatalk

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