Negative -5volts for coin lights and +10 unregulated for logic boards

[vanwatson]

Why does Arcade games use a Negative -5volts for coin lights?

Some logic arcade boards use a +10 unregulated voltage for logic boards, why is it unregulated?

[ed12]

well u have me on the -5 volt for light's,never heard of it
as a rule older board's used the -5 and or -12 volt rail's for sound/video
>old board's<

now for the un-regulated 10vdc pack series has a on board 5volt regulator
which is fed from the 10v feed
these were replaced with the smps power supply,when it took over as the power
supply of choice over linear

ed

[vanwatson]

So the Logic boards that have a 10 VDC unregulated input has a + 5 volt regulator on the logic boards?
But most linear power supplies have regulators build in already

Yes most arcade games in the 80's coin lights used the -5 volts , not sure why they used -5 volts

Or what have you seen that uses negative - 5 volts in arcade games?

Why did they use the sound board at -5 volts and not at +5 volts

Also the Volume pot is rated at 10WATTS , these volume pots rated at 10 watts are not common to get at the store
any reason 10 watts for a volume pot?

[ed12]

older game board's used older analog audio/video circuit's >not all in 1 ic chip style<
so they had to :swing: between the power differnical's ie +5 to -5
by early to mid 80's this was done away with in favour of single side rail
ie +12 +5 even though some smp's still have -5 or -12,it is rarley used

ed

[vanwatson]

older game board's used older analog audio/video circuit's >not all in 1 ic chip style<
so they had to :swing: between the power differnical's ie +5 to -5
by early to mid 80's this was done away with in favour of single side rail
ie +12 +5 even though some smp's still have -5 or -12,it is rarley used

Yes true

The Audio chips are signal ended rails

The audio amplifiers in 80's arcade units are different because the volume pot is rated at 10 watts, you can't us a regular volume pot because of the wattage needs to be at 10 watts

 

[ed12]

correct,because the wiper is tied to 1 side of the speaker
the control is across the diff output's
which give's u 10 watt's max

ed

[vanwatson]

correct,because the wiper is tied to 1 side of the speaker
the control is across the diff output's
which give's u 10 watt's max

So the volume pot is for the power amplifier

Most volume pots are for the pre-amplifiers

I wonder why arcade games wanted the volume pot for the power amplifier

It seems like the volume pot can be a "Balance control" for Left/right stereo since the wiper is to the speaker

 

[ed12]

90% of the pre late 80's game's were pure mono
no blance nessary,but to get the power u needed to bridge a dual channel
ic amp,u see at 1 time ic amps olny had xx thermal cap..ie will hit top temp when driven beyound xx wattage,they would go into what is called thermal runaway,
so game mfg's took a dual channel 5 watt amp bridged it and used the 10 watt
pot as the over all volume control by playing with the differnecial's
ie 1 side pushed + of the sine wave the other pulled the - side of the wave
thus doubling your power but keeping it thermal stable

ed

[vanwatson]

no blance nessary,but to get the power u needed to bridge a dual channel
ic amp,u see at 1 time ic amps olny had xx thermal cap..ie will hit top temp when driven beyound xx wattage,they would go into what is called thermal runaway,
so game mfg's took a dual channel 5 watt amp bridged it and used the 10 watt
pot as the over all volume control by playing with the differnecial's
ie 1 side pushed + of the sine wave the other pulled the - side of the wave
thus doubling your power but keeping it thermal stable

:What a nice little trick they did:

So they are bridge a dual Preamp ? Bridging the outputs of two channel preamp outputs?

Because if you tied two outputs of a power amp it will blow the power transistors or IC outputs

Are the Dual Channels at opposite polarities / 180% out of phase with eachother?

 

[ed12]

yup

ed

[ed12]

if it up-loads ?

ed

[vanwatson]

Yes I see the single Differential op amp that has 2 outputs that are differential

But you're saying that it's Two Op amps , two Channels that the outputs gets summed/bridged together by the 10 watt pot

[ed12]

yes correct

ed

[Ken Layton]

I have NEVER encountered an original dedicated machine of any type that used a "-5 volts" to run the coin door lights.

However, I have encountered many converted game cabinets where people have rewired things and they connected the -5 volts of the power supply to the coin door lights. This is NOT the proper way to light up the coin door. The reason being is that ALL switching power supplies have no overload or short circuit protection on the -5 volt and +12 volt outputs. So if a short circuit happens or the wrong bulbs are put in, the power supply gets damaged (usually blows a diode in the output section of the power supply) then the fuse blows. 

The correct way to power the coin door lights is to run them from the +5 volts section. That part of the power supply is protected. It will shut itself down until the short circuit or overload condition is cleared. The power supply will not be harmed this way.

As to games with a +10 volts unregulated, some games like Midway and Atari use the +10v unregulated to power the coin counting meter.

[vanwatson]

As to games with a +10 volts unregulated, some games like Midway and Atari use the +10v unregulated to power the coin counting meter.

Yes true i have seen some coin countering meters powered by +10 volts unregulated and other coin counters meters powered by +5 volts

What is the difference between a coin counter metered powered by +10volts VS a +5 volts coin counter meter? they do what differently

The reason being is that ALL switching power supplies have no overload or short circuit protection on the -5 volt and +12 volt outputs.

Do you mean the -12 volts?

I'm not sure why they would make NO short circuit protection or Over load for the negative supply but only for the positive supplies

[vanwatson]

Why would they use Unregulated +10 volts and Not use Regulated +10 volts?

Unregulated would have ripple and noise

Mostly Logic game boards don't like ripple and noise because it causes display issues

I have seen the Unregulated go straight to the logic boards to power them up, i have no idea why they would use Unregulated DC voltage

[Ken Layton]

As to games with a +10 volts unregulated, some games like Midway and Atari use the +10v unregulated to power the coin counting meter.

Yes true i have seen some coin countering meters powered by +10 volts unregulated and other coin counters meters powered by +5 volts

What is the difference between a coin counter metered powered by +10volts VS a +5 volts coin counter meter? they do what differently

The reason being is that ALL switching power supplies have no overload or short circuit protection on the -5 volt and +12 volt outputs.

Do you mean the -12 volts?

I'm not sure why they would make NO short circuit protection or Over load for the negative supply but only for the positive supplies

No, I do mean +12 volts. The vast majority of commercial coin operated arcade games do not use -12volts.

[vanwatson]

No, I do mean +12 volts.

'

So switching power supplies don't protect the +12 volts? why not protect it

Why not have short circuit protection and over load protection for the +12 volts

[jennifer]

    My thoughts would be cost factors, Who wants to buy a 200.00 P/S when a quick blow fuse would suffice in most circuits.

[vanwatson]

So it is true for Linear power supplies when you adjust the +5vdc it increases/raises the current amps output also?

On switching power supplies when you adjust the +5 volts it "doesn't" increase/ raise the current amps output?

[ed12]

to the extent correct
smps put out a steady voltage give or take .6 volt
linear on the other hand can run up/down about 3volt's
i pick smps for stable supply
the +12v there is no real need,it is controled by the +5v
just snag a smp's supply schematic and u will see how..
if need i will snag u 1

ed

[vanwatson]

Yes true some Switching power supply adjust knob is shared/ganged with the +5volts and +12 volts, so when you more the adjustment knob up or down both +5vdc and +12vdc go in unison

There is other Switching power supplies that adjust the +5 volts only

Switching power supply that has 2 adjustment knows for +5 volts and +12 volts

You have to adjust the voltages on the logic boards "test points" not from the power supply output or edge connector

For some reason the Logic Boards Test Points are taking off at a different part of the logic circuit

Do you guys know where these + 5 volts and +12 volts Test Points are tapping off in the logic circuit

Because you have to adjust the voltages to the Logic boards test points at 5.2 VDC and 12.2VDC

 

[lilshawn]

really the only power supply that matters is the +5 which runs all the game logic which is very susceptible to power dips and ripple.

often +12 volts is only used to run lights/motors/audio systems and other passive components that don't really matter if the voltage is off by a little since these systems aren't affected as much by being off by a volt or more.

[vanwatson]

What is the highest voltage that you put on the + 5volts? is the highest 5.4 volts or can I go higher?

I know games are very sensitive to the 5 volts, if you go 4.8vdc  the game will cause display garbage and other errors, and if you go to 5.6vdc the game will cause weird stuff and errors

Any reasons why game logic boards are so sensitive to the 5 volts range? it has to be set in that sweet spot

[lilshawn]

TTL integrated circuits rely on a constant unvarying +5v.

it's common to have some drop across the board of a few millivolts. if you find the IC furthest from the power input and measure the VCC pin for the 5 volts. if it's way low you may have a corroded connection where the 5 volts comes in.

if it's a little low adjust the power supply to output 5.0v at that point. be sure to watch it as the game runs as it may sag down a bit into the 4 volt range as the different IC's get switched on and off.. if it does, bump it up a tiny bit to keep the lowest voltage at that point above 5.0 volts.

[ed12]

as u have been back and forth on this,here d/l this
it is a clear look see at a smps
u will catch the drift why the ony manage the +5volt rail

ed

[vanwatson]

If you put the Coin Lights and other pulsating lights on the +5 volts rail , you will get a push/pull DC level shifting when the coin lights and other pulsating lights are drawing the current and releasing the current. Plus the lights cause noises and ripple on the +5 volts rail.

If you isolate the coin lights and pulsating lights on the -5 volts supply , you won't have this problem

The Logic game boards don't like ripple or noises on the +5 volts, it will logic errors and display garbage on the screen I have noticed

[ed12]

where i can see u are confused..allow me to clear something up for u
today's :flashing: circuit's make provision's for the fold-back-current u speak of
older circuit's had a fourm of if,but the snubber's just  in some case's was
not quite good enough

ed

[vanwatson]

power supply fold-back-current

How does the power supplies fold back current fix the light flashing voltage fluctuation problem?

The power supplies fold back current does what when the voltage is fluctuation from the lights flashing?

[ed12]

the term is used when u have un used current,voltage
it must go some where..well the start is as good a spot as any u think.?
hence the reason u see blocking diode's at time's >they snub fold back current<

ed

[vanwatson]

the term is used when u have un used current,voltage
it must go some where.

This is called the "idle current or Idle Voltage"

So you're saying that the Fold back current circuit sinks/drains off the Idle current and Idle voltage?

[ed12]

This is called the "idle current or Idle Voltage"

NO NO NO

there is no idel current and or voltage to this
IT IS CALLED FOLD BACK FOR A REASON
the term is perty self exploranity..the current is folding back
has ---steaming pile of meadow muffin--- to do with idel...

ed

[vanwatson]

So when a light is flashing the current gets folded back? how does the current get folded back when the light is flashing?

[ed12]

there alway's be xx of fold-back..it depend's on how u stop it
best way is a blocking diode and a small cap .01 or such

ed

[vanwatson]

there alway's be xx of fold-back..it depend's on how u stop it
best way is a blocking diode and a small cap .01 or such

oh ok , So i have to install external blocking diode and .01 cap on the flashing light circuit or on the + 5 volt rail?

[vanwatson]

Look at Page#14 it will show you a diagram of the coin lamps wired to the -5 volts

http://www.crazykong.com/manuals/Quarterback.man.pdf

Many games I have seen do this , it was very normal

[ed12]

not really
they did it,or rather it was used to :balance: the load of the smps >switcher< p.s
and it is easy to tell as there is no feedback line >which would shut down the smps<
in case of a over load..look the p.s schematic over very colse..
now most ppl went away from this...
and most never said it could not be done..it is just not the norm

ed

[vanwatson]

The -5 volts goes also to the amplifier sound board. It says in manuals do NOT hook up the lamps to the -5 volts because it will induce noises , buzzing, flicking on the -5 volt rail to the amplifier IC

Old 80's power supplies:
But there is some power supplies that have a + sense terminal and a - sense terminal

I'm not sure what the "sense" terminal is or does

Maybe it was a current sensing circuit

[ed12]

ya it's 50/50
sense what u know ?
unless it is listed as to what,right...
ie if u want to say a atx power supply
then it means current good
this is the same as >ps< good or good to go
u can read up on power supply's until your eye's bleed
and end saying wtf ?
cold stone crap here
atx=power-on=green-wire-to-ground
u by-pass power good line...so why put it there,?? good q??
humm it was to be used for ppl with the proper test >load< eq....,
but with sooooo many back door ppl it was thrust up-on-us
so we can by-pass and walk-away
it by no means i fixed the UNDER-LYING PROBLEM
but rather i fixed the machine
it's rather condovoleted

ed

[vanwatson]

Here is the schematic for the SENSE - and SENSE + , what are they?

The Power supply for the Major Havoc arcade game

Page#3
http://www.crazykong.com/manuals/MajorHavoc.sch.pdf