williams system 11b cpu problem

[pinball-collector]

hello all,,,l have a problem,,,with my police force,,, system 11b cpu board,,,the thing is dead,,, all 3 leds are dead,,, their apears the be power to the cpu,,from the power supply board,,all the plug connectors apear to be fine,, no display, nor  the  game will boot,,no led indercators flashing,,,lm no tech head,, just have lots of pinballs,, that been in storgae for a while,, and its time to start to get some of the working,, lm happy tp leard,,the police force,,was working fine, untile l put it in storage for a couple of years,, the only damage l could see,,is one of the large chips, the is piggy backed, has some green, corrsion,,on 4 or so legs,, all i did is lifted it out, and pushed it in again,,with no difference,,needs to be replaced,,but dont think that will kill the whole board,,,any ideas???
regards john

[Steevsee]

Are the batteries still on the board?  Sounds like maybe some acid damage to the PIA chip.
See Clays guide for test/Repair info http://www.pinrepair.com/sys11/index.htm
You can test the CPU with Leon's test Eprom.

Did you test the voltages from the Power supply board?

[shansta]

Yep - green is NOT good!

Yes it (battery corrosion) will kill the board stone cold!

Go back to your storage and remove the batteries from every machine you have in there!

Do it yesterday...

[ddstoys]

Yeah sadly it sound like battery corrosion which could lead to many issues.

  Thake Shanstas advice and governing every battery yesterday or you may face this with every game

[pinball-collector]

Thanx for getting back to me,, lucky for me the betters are external,,not located on the cpu,,someone did that befor l got the machine,,yes l did take all the batters from the machines, befor storage,,, kids had plenty of AA batterys for there toys..

ok,,here is what l found,,lm only a newbie,,willing to learn..

power supply seems to be ok,, putting out  5v and +12v

With the sound and cpu board unplugged,, power supply putting out 13.7v at TP3 and 5v at TP1

With sound bord only plugged in getting 13.7v at TP3 and .9v at TP1

With sound and cpu plugged in getting 13.7v at TP3 and .6v at TP1

With cpu unplugged  and sound board pluggrd 1.1v at TP3 and 1.0v at TP1

dont think the sound board has anything to do with it, the whole cpu has only .7v over the whole board.no 5 volts anywhere, on cpu,, playfied and light box lights are dim,,like something draining..

those piggy back connectors at U41 and U51  has some green,, in the connector holes,,need to be replaced,, unsure if it right,,but used some 1200 to lightly clean the legs, befor plugging in the chips..

any ideas??

[Homepin]

it seems like either the power supply is unable to supply enough current or (more likely) there is something on the board shorting the 5V rail. You need to STUDY the Clays guides very carefully OR get some professional assistance to find your faults.

There are plenty of places you can have the board checked out and repaired.

That would be my advice if you are not technically inclined - get one machine going and learn to fix the smaller problems first before tackling something like this that is likely to be far more serious and also, you may end up causing more damage or worse - make the board UNREPAIRABLE at ALL!

[MartyJ]

Quite often when working on CPU boards, I've got a JAMMA power supply which I use to boot the boards on the work bench. 

A good way to isolate it and test properly.

[shansta]

Dumb question time. (I'm blonde ok)

Did you test it with the sound board unplugged? i.e. CPU only?

What does the 5v supply do with the CPU only?


Reading your post - the 5v supply drops to 1v when the sound card is plugged in? (But not the CPU board)

That don't sound right to me?

[pinball-collector]

hello,,may have to send it out, to get repaired,,the closest machine to change over boards, to test is my High speed,, but dont wanna screw up my high speed board..

when l first checked it the power supply fuses f2 was blown and f1  that neraly tricked me,,it buzzed with the mm,,, untill l took it out from the holder,,that was blown too

with all points unplugged from the cpu,,with only the power supply to plugged in, and sound board unplugged,, its still only .7v at the TP2 point, onthe cpu,,the whole board is the same..
TP 1 Ground comes up as 00 ohms,, have been following the repair guide,,like its shorting out neat the connerctor somewhere,,connector look fine,, my mm is not the best,,testing it at DC? is that correct.

might be time to upgrade some toolss

[pinball-collector]

ok,,, with sound board plugged in only,, showing 1.0 volts,,,with the cpu pluged aswell,,getting only .6 volts,, both unpluged,, getting 5volts at the connector,, is it fair to say the power supply is loosing power under load?,,

[MartyJ]

ok,,, with sound board plugged in only,, showing 1.0 volts,,,with the cpu pluged aswell,,getting only .6 volts,, both unpluged,, getting 5volts at the connector,, is it fair to say the power supply is loosing power under load?,,

Do you have a JAMMA (arcade power supply) at home?

[pinball-collector]

no nothing here,,only complete arcade machines in storage

[Steevsee]

You can also use a computer power supply to benchtest the CPU board - Clay's guide shows how to hook it up.

Basically you need to connect the CPU board to a known good power supply voltage(Arcade or Computer), with nothing else connected, and see if it boots or not.
If it won't boot on the bench then you know the problem is definitely on the CPU board and not on your power supply board.

You can then either send it for repair or attempt repairs yourself, but read Clay's Beginner guide before attempting any repairs. http://www.pinrepair.com/begin/index.htm
If you don't have much PCB soldering, or more importantly, DESOLDERING experience you are probably better to send it out, as these boards can easily be damaged.

[Homepin]

ok,,, with sound board plugged in only,, showing 1.0 volts,,,with the cpu pluged aswell,,getting only .6 volts,, both unpluged,, getting 5volts at the connector,, is it fair to say the power supply is loosing power under load?,,

Not neccesarily - the board could have a short somewhere that loads the power supply down.

[pinball-collector]

Ok , thanks for your help guys,, l open up my High Speed, and swapped the cpu boad over, into the Police force,, just connected up the power supply,,yep,,same thing.

low .6 volts from the power supply,, disconnected, power supply ,puts out , the normal 5.0 volts,, unless lm wrong,,the power supply , dont work under load, the board did have a blown TP2 fuse, when l first looked at it, the board also had a lot of work done befor,, lots of soldering, traces buzz out ok,,yes the High speed was working fine.

the power supply puts out 14 volts + and -  is that ok??  who sells, a power supply repair kit,, or shell l buy a new one from rottendog,,for about $75 US,,like to have a go repairing.. does it make sense what im saying?

regards John