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PINBALL WITCH
Joined: 03 Aug 2005
Posts: 166
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 Posted: Fri Sep 02, 2005 6:41 am Post subject: Help switch question |
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Can someone pleases explain how adding a diode to a leaf switch impacts the way the switch works?
If the bom calls for a switch without a diode can one be used if it has a diode soldered on?
I know if it calls for a diode it has to have it.
Thanks for your help
kim |
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Swann
Joined: 02 Aug 2005
Posts: 108
Location: Stockholm, Sweden
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| Posted: Fri Sep 02, 2005 7:23 am Post subject: |
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Just a quick reply since I'm about to leave here at work.
If the switch is connected in a so called Switch-matrix there has to be a diod so that when the software scan's/strobe's there won't be any detection of other switches (that is a switch in a matrix doesn't have a dedicated I/O port to the CPU).
...but if the switch has a dedicated I/O port directly to the CPU there is no need for a diod.
Of cause there could also be a lots of other electrical reasons why one would place diods (or not) on different locations but above is the most normal reasons.
To answer your question, if one can use one with a diod where you don't need one, the answer is 'generally yes'... One have to look into the circuitry to give a exact answer.
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jadziedzic
Joined: 02 Aug 2005
Posts: 151
Location: Nashua, NH USA
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| Posted: Fri Sep 02, 2005 10:40 am Post subject: Re: Help switch question |
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| PINBALL WITCH wrote: | Can someone pleases explain how adding a diode to a leaf switch impacts the way the switch works?
If the bom calls for a switch without a diode can one be used if it has a diode soldered on?
I know if it calls for a diode it has to have it.
Thanks for your help
kim |
Kim, the answer is "it depends on the specific application". As someone already mentioned, the diode is used in matrix configurations to allow the game to detect operation of discrete switches without requiring individual connections to each switch. Williams uses this technique in their games.
Capcom wired each switch individually to a "switch board" with electronics that detects each switch individually. The presence of the diode will probably confuse the game electronics, especially if the diode is wired in one direction or the other.
My guess is that it won't work, or will cause problems. If you'd like to shoot me a copy of the schematic and the switch specifics I'd be glad to give you a more specific answer.
Tony Dziedzic
(Kim, if you'd like to chat personally about this, my e-mail is tony@dziedzic.us; cell is 603-682-6750.)
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Joseph "Tony" Dziedzic
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PINBALL WITCH
Joined: 03 Aug 2005
Posts: 166
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| Posted: Fri Sep 02, 2005 12:45 pm Post subject: |
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Thanks you gentlemen,
Part of our switches have the diode, the majority don't. Had me worried
kim |
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pinball-sales
Joined: 06 Aug 2005
Posts: 32
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| Posted: Sat Sep 03, 2005 7:11 am Post subject: Diodes |
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I would say if the diode is not on the switch itself, it maybe either on a diode board or even on the driver board itself.
Be careful to put the diode on the right way around or it will cause lots of switches to work at the same time.
Capacitors were used on older games to help detect a ball hitting a switch
if the switch was hit too quick is sometimes did not register. |
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unigroove
Joined: 08 Aug 2005
Posts: 118
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| Posted: Sun Sep 04, 2005 3:34 pm Post subject: |
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Kim, you just made me relive the month I spent with you guys: diodes, diodes, diodes....
If the specifications call for a diode, use it. Basically what a diode does it allows the current to flow only in 1 direction. Therefor it is very important all diodes are installed in the correct position. You can tell by a small band that is printed on one side of the diode. With lampholders and switches all diodes usually are mounted in the same direction. If this gets messed up I foresee big problems once installed the wrong way.
be carefull
Jonathan |
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BigBangJoe
Joined: 02 Aug 2005
Posts: 134
Location: Gent, Belgium
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| Posted: Mon Sep 05, 2005 4:36 am Post subject: |
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| unigroove wrote: |
If the specifications call for a diode, use it.
Jonathan |
Jonathan, Kim's question was the other way around: if the switch shouldn't have a diode, is it a problem that there is one connected?
Joe |
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awarner
Joined: 02 Aug 2005
Posts: 558
Location: Atlanta, GA
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| Posted: Mon Sep 05, 2005 6:17 am Post subject: |
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From Clay's Site:
| Quote: | Capcom had the great idea of not mounting a diode on each playfield switch. Instead, the diodes were mounted on a long skinny switch matrix board in the back box. This made switch replacement easier for the operator.
In the case of all the other pinball manufacturers, they would run a single switch Row and Column wire to a playfield switch, and then daisy chain the rows and columns to each switch. Also each switch had its own diode. Also there was but one connector for the eight switch row, and one connector for the eight switch columns.
But in the case of Capcom, since each switch's diode was remotely mounted on the switch matrix board in the backbox, a two separate wires were needed for each of the 64 switches! This meant instead of two 8 pin connectors (16 wires total), on Capcom games there are 64 wires (plus ground wires). And of course this means there are way more connectors for these additional wire (all are the smaller .100 style connectors too). More connectors are bad, as reliability suffers (most Capcom connectors are the IDC type). |
That said, the switches with diodes should have them cut off to avoid any logic problems.
-Al-
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christian1
Joined: 02 Aug 2005
Posts: 36
Location: Richmond, TX
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| Posted: Mon Sep 05, 2005 11:48 am Post subject: |
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Wouldn't it be just as easy to open up Gene's BBB and physically look at the switches?
Jon
| awarner wrote: | From Clay's Site:
| Quote: | Capcom had the great idea of not mounting a diode on each playfield switch. Instead, the diodes were mounted on a long skinny switch matrix board in the back box. This made switch replacement easier for the operator.
In the case of all the other pinball manufacturers, they would run a single switch Row and Column wire to a playfield switch, and then daisy chain the rows and columns to each switch. Also each switch had its own diode. Also there was but one connector for the eight switch row, and one connector for the eight switch columns.
But in the case of Capcom, since each switch's diode was remotely mounted on the switch matrix board in the backbox, a two separate wires were needed for each of the 64 switches! This meant instead of two 8 pin connectors (16 wires total), on Capcom games there are 64 wires (plus ground wires). And of course this means there are way more connectors for these additional wire (all are the smaller .100 style connectors too). More connectors are bad, as reliability suffers (most Capcom connectors are the IDC type). |
That said, the switches with diodes should have them cut off to avoid any logic problems.
-Al- |
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bbb96
Joined: 02 Aug 2005
Posts: 11
Location: Saginaw, MI
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| Posted: Mon Sep 05, 2005 12:35 pm Post subject: Re: Help switch question |
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| PINBALL WITCH wrote: | Can someone pleases explain how adding a diode to a leaf switch impacts the way the switch works?
If the bom calls for a switch without a diode can one be used if it has a diode soldered on?
I know if it calls for a diode it has to have it.
Thanks for your help
kim |
Kim,
When in doubt, I would verify the BOM against Gene's Big Bang Bar for any diode / switch assemblies. In fact, use Gene's machine for any questions you have about the BOM. This will be an easy way to check the accuracy of the Bill Of Materials.
If Gene's machine has the diode on the switch, leave the diode on the switch.
If Gene's machine doesn't have the diode on the switch, don't use a diode on the switch.
- Jeff |
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bbb96
Joined: 02 Aug 2005
Posts: 11
Location: Saginaw, MI
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| Posted: Mon Sep 05, 2005 12:46 pm Post subject: |
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I agree with Jon - use Gene's machine for reference.
I just checked my Breakshot schematics along with the actually machine and the diodes ARE installed on the switches and there is not a diode board in the backbox for the switches.
SUMMARY: Use Gene's machine as your reference.
- Jeff
| christian1 wrote: | Wouldn't it be just as easy to open up Gene's BBB and physically look at the switches?
Jon
| awarner wrote: | From Clay's Site:
| Quote: | Capcom had the great idea of not mounting a diode on each playfield switch. Instead, the diodes were mounted on a long skinny switch matrix board in the back box. This made switch replacement easier for the operator.
In the case of all the other pinball manufacturers, they would run a single switch Row and Column wire to a playfield switch, and then daisy chain the rows and columns to each switch. Also each switch had its own diode. Also there was but one connector for the eight switch row, and one connector for the eight switch columns.
But in the case of Capcom, since each switch's diode was remotely mounted on the switch matrix board in the backbox, a two separate wires were needed for each of the 64 switches! This meant instead of two 8 pin connectors (16 wires total), on Capcom games there are 64 wires (plus ground wires). And of course this means there are way more connectors for these additional wire (all are the smaller .100 style connectors too). More connectors are bad, as reliability suffers (most Capcom connectors are the IDC type). |
That said, the switches with diodes should have them cut off to avoid any logic problems.
-Al- |
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mushroom
Joined: 18 Aug 2005
Posts: 86
Location: Belgium
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| Posted: Mon Sep 05, 2005 1:24 pm Post subject: |
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Euhm,
You really can't compare Breakshot to the other Capcom games as it has a completely different boardset. Breakshot is the only one with that boardset, all the others have the standard "high level" boardset. |
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jadziedzic
Joined: 02 Aug 2005
Posts: 151
Location: Nashua, NH USA
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| Posted: Mon Sep 05, 2005 5:56 pm Post subject: |
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No need to continue to worry about this issue; I spoke with Kim Friday afternoon after her posting, and she's all set.
Tony
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Joseph "Tony" Dziedzic
BBB #39 |
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pbgarage
Joined: 02 Aug 2005
Posts: 15
Location: Corpus Christi, Texas
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| Posted: Wed Sep 07, 2005 3:16 pm Post subject: |
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All of the first BBBs are protos, and therefore that's not
a reliable option. Each one has differences between them.
Fred
TX
CARGPB#8
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[quote="bbb96"]I agree with Jon - use Gene's machine for reference.
I just checked my Breakshot schematics along with the actually machine and the diodes ARE installed on the switches and there is not a diode board in the backbox for the switches.
SUMMARY: Use Gene's machine as your reference.
- Jeff
[quote="christian1"]Wouldn't it be just as easy to open up Gene's BBB and physically look at the switches?
Jon
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Fred
TX
CARGPB#8
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unigroove
Joined: 08 Aug 2005
Posts: 118
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| Posted: Wed Sep 07, 2005 4:16 pm Post subject: |
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| as far as I can recall I did not see any switch or lamp socket on Gene's machine that without a diode... |
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