Arcade games very Picky about the +5 volts

[vanwatson]

Why are Arcade games very picky about the +5 volts range? some Arcade games are very picky about where the +5 volts voltage has to be.

What is making the logic boards so picky about the +5 volts?

Is it the ROM chips or RAM chips that make the +5 volts so picky?

Because you have to fine tune the +5 volts on some arcade logic boards to not get display errors or other logic board errors and problems

You can put the Arcade into TEST MODE, and adjust the +5 volts higher. Test the ROM/RAM chips in Test mode and you will get Errors tell you which ROM/RAM chip is bad just from the +5 volts at 5.1vdc to 5.5vdc

If you measure the Test points on the Logic boards it will measure 5.1 volts, but when measuring the output of the power supply it will be at 4.8 volts.

Their is mostly multiple +5 volts and ground Test points on arcade logic boards. These test points can't be the power supply rails because there is a difference and discrepancies because each +5 volts to ground.   

[ed12]

what and huh ?
ttl love's 5 volt
at the power suppy may be bang on 5volt
u are required to chk at the board in question header and or test point for 5volt..
read the spec on ttl 4.6-5.3vdc
go under over u get goffie problem's
board's that reset,board's that lock -up,etc
5 volt is there very very genric term..it has crap to do with ram/rom pre-say
it has to do with the over-all way ttl logic work's
if u want a board to work right u make sure u have 5volt on the :board:...
on the board u will see a wack of .01 by-pass cap's >cermaic< and u will find
1-10mf filter's
the .01 are for fold-back >we went over this < the filter's 1-10mf are there to not olny filter,but to help keep the 5volt rail up,some time's u will see 100-220mf cap's
same ---steaming pile of meadow muffin--- dif value..depending on current used,they are :alway's: on the power line's

ed

[vanwatson]

So the decoupling Caps .01uf are for current fold back?

I thought the decoupling caps are for to filter out TTL and CMOS switching noises and ripples

Yes anything under 5 volts will cause the CPU to not operate right

Put the Game into TEST MODE , and go to the test ROM/RAM chips. Now adjust the voltage below 5 volts and you will get ROM's and RAM chips at certain locations saying bad. Now adjust the voltage ABOVE 5 volts and you will get ROM's and RAM chip errors at certain locations saying bad ROM and RAM chips.

There is arcade games that will say you have BAD ROM and RAM CHips at certain locations because the it's at 5.1 volts or 5.3 volts. But when you adjust the power supply to 5.2 volts the arcade machine will not give errors. It's picky about the + 5 volts but why? what is causing this

[ed12]

ttl logic....about that simple
it can not, nor be any clearer

.01 are de-coupler's
again about that simple

1-10mf are line ripple filter's
about that simple

ed

[jennifer]

     Is Jennifer missing something here?
     So you have a specific voltage problem?
     On certain games?... So we"re dealing with multiple boards?
     Don't these boards have any voltage regulators on them?

[vanwatson]

Any reason why the +5 volts is at 11amps for arcade games, The Logic board needs 11amps of current that is overkill i would think just for TTL and CMOS chips

Where does all those 11amps go to because TTL and CMOS chips don't need 11 amps of current

The +12 volts VDC is at 1 amp, The 1 amp of current goes to the audio circuit board

[jennifer]

     Again.... "For arcade games", You are aware of the fact they are not all created equally right? And this P/s you keep referring to, is it something that was shoved into a Ms. pac, Or a Hang on or what? Perhaps some random Switcher from Epay?.... Older games had some very large boardsets,
11 amps may seem excessive (Enduro Racer for example) Suppose it draws 8amps (again for example) that would leave a difference of a 3 amp potential, yes its to big But the load only takes what it needs.

[vanwatson]

Yes some arcade games +5 volts is at 8 amps it say in the arcade manual and other arcade games are at +5 volts at 11 amps. Both are very common in the 80's arcade games plus they has 3 series pass transistors on heaksinks to have such a very high current output.

My question is why 8 amps or 11 amps at 5 volts? TTL and CMOS chips don't draw that much current or a current load

[jennifer]

   Not one maybe.... But get a couple hundred or so together and they start drawing some current.

[ed12]

do some math here
1 chip =200ma-x10=2a
that is just 10 chip's less my line loss/board loss getting to said chip's
11 amp's is not that far out of reach..think what was told to u
at 100 chip's what current do u think they would draw ? and do not use single base line,use running full tilt as your base line,it will dawn on u and real fast

ed

[vanwatson]

Well if the logic board has mostly TTL chips  , yes TTL chips draw way more current then CMOS chips

The Monitors board and deflection board must use most of the current because it has power transistors, RGB output transistors and needs a lot of current to drive the flyback transformer

[ed12]

>The Monitors board and deflection board must use most of the current because it has power transistors, RGB output transistors and needs a lot of current to drive the flyback transformer<

has 0 to do with ttl logic period
monitor's operate on the own power-supply's that simple

ed

[vanwatson]

I'm talking about the circuit board that the monitors adjustment pots for RGB, focus, screen , vertical oscillator, horizontal oscillator , horizontal coil, flyback transfomer

The + 5 volts goes that that board, I think they call it a monitor deflection board , this much use 11 amps of current

 

[ed12]

dude u are confused

+5 volt never never get's to the monitor
it is that simple,get it in u,and understand,the monitor is a sperate unit on to it's own
sep power supply the full way....now if u want to talk x-y then say so please
that is a total dif anmial then chorma..
x-y will take a deriect ttl load..but not at 11 amp's
might as well put a crowbar in there instead
ttl load at 11 amp's is not that out of reach if u do some simple math
100-x-200=? we will do it easy
100 units's x 200=mila-amp's give or take a few u fudge..u will get it ?
so where do u get this head room for chroma takeing 11 amp's??
no no no for the last time
it is ttl load,mpu/cpu >same xhit< dif name /cmos/ram/rom
that my bud is your load

ed

[jennifer]

    Relax Mr12 ... Breathe slowly...1...2...3.... AND (Happy Place). 

[ed12]

jennifer ya i know...and thk-u :sexie:..
just asking the same q over and over when the answer is right in there
make's yer head swim......
love your bod btw

ed

[Ken Layton]

Perhaps Van would do best to sign up for Randy Fromm's repair classes?

[DaOld Man]

Hey Van, you any kin to a guy called Driverman?

[SavannahLion]

Hey Van, you any kin to a guy called Driverman?

That's who he reminds me of.

Did you read his comic from a couple of years ago?