midway space invaders white screen ?

riche100

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further update with power on and board disconnected using the (music note setting for continuity) on my meter measuring from the power supply to the pin on the edge connector i have the following

my pin numbers ...



: pin 14 ground

: pin 4 -5

: pin 5 ground and -5

: pin 16 12v

: pin 14 -5

: pin 16 -5

: pin 18 -5

: pin 18 +5

: pin 16 +5

seems odd to me some pins can have cont at ground and also -5 ? and so on ?


all my pins are backwards to look at which doesnt help , ive managed to match wires ok on new edge connector put put the numbers on the wrong way round

so pin 18 ia actually pin 1 and so on to confuse further




...........





on my other midway the wires are in the same positions ?






when ive taken the cont readings today i havent got a gameboard installed and i wont . as ive just forked out alot of money with irongiant to have one fixed ?

meter readings again today from supply were :

-5 5.00

+5 5.01

12v 12.00

and on ripple setting

-5 0.00

+5 0.00

12v 0.01

when i did cont readings no gameboard was installed and i was taking readings from power supply to pin inside edge connector

i only have togo on the cabs i have before me , seems odd they both wired the same ? and neither work , just show a white screen ?





thing is too , i can only go on what the seller told me and he said one worked and used to play it then one day didnt work

so i persumed neither had been fucckered with ? infact i still dont know if they have / i cant see any loose wires and they all seem to be original wiring ??

anyway got a bog standard midway si they can show me pic of there edge conenctor please?

again all ive done is copied the pins and there spacings inbetween ? albeit with the edge connector numbers and letters upside down







wires are as follows from the top of the connector down :

red/wht pin no 18 on original edge connector
blu/wht
_
org/red
red
_
_
_
_
_
_
_
_
blk/wht
_
bwn/wht
_
white pin 1 on original edge connector





as you can see 2 wires from the top direction of the cab into the conenctor








and the rest from bottom of cab up into connector 5 of :



please help :(
 
Last edited:
Dam I knew you needed it I could have snapped a picture of one. I going to catch up with a friend in a few days and If nobody steps up I wil..

From the this site

http://www.brentradio.com/SpaceInvaders.htm

+5v DC A 1 +5v DC
+5v DC B 2 +5v DC
+12v DC C 3 +12v DC
+12v DC D 4 +12v DC
-5v DC E 5 -5v DC
No Connection F 6 No Connection
KEY H 7 KEY
No Connection J 8 No Connection
No Connection K 9 No Connection
No Connection L 10 No Connection
No Connection M 11 No Connection
No Connection N 12 No Connection
No Connection P 13 No Connection
Ground R 14 Ground
Ground S 15 Ground
Ground T 16 Ground
Ground U 17 Ground
No Connection V 18 B+W Video Signal

There is not many wires that go to your edge connector. Odd I never heard of a SI with a bad edge connector.

There are caps on the sound board.
If you have a Volt meter you can read the voltages across cap c43 You should see 12 volts across the cap. Circle in yellow. The cap circle in red should be 5 volts.
 

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Did you look at the resistance or just listen for a tone? The tone gets played if the resistance is below X (not at zero). Some circuits are OK that way. Measure the resistance between these pins WITH THE POWER OFF and let us know what you find.

ground and -5v:
pin 5 and ground:
pin 5 and -5v:

: pin 5 ground and -5

seems odd to me some pins can have cont at ground and also -5 ? and so on ?
 
bang on

if just checked voltages and guess what they are bang on or as near on ?? at edge connector

-5 was 5.00
12v was 11.99
+5 was 5.00

so even though game still doing jack thats good yes ?

no what ha ha ? still getting white screen , no game play , doesnt play blind doesnt coin up ? boards fixed 100% tested and working on a test rig

any ideas fellaz ?
 
[QUOTE

There are caps on the sound board.
If you have a Volt meter you can read the voltages across cap c43 You should see 12 volts across the cap. Circle in yellow. The cap circle in red should be 5 volts.[/QUOTE]

using volt meter set on dc with the game running on red cap i get reading 0.50

and on yellow ringed cap 11.98

thats using a gameboard i dont know the history of . scared of plugging good board in as of yet ?

are my findings good or bad news ?
 
[QUOTE

There are caps on the sound board.
If you have a Volt meter you can read the voltages across cap c43 You should see 12 volts across the cap. Circle in yellow. The cap circle in red should be 5 volts.

using volt meter set on dc with the game running on red cap i get reading 0.50

and on yellow ringed cap 11.98

thats using a gameboard i dont know the history of . scared of plugging good board in as of yet ?

are my findings good or bad news ?[/QUOTE]

Bingo ! If the red cap is only 0.50 volts It means something is shorting out the 5 volt section of the board.

You said that the game is working on a test rig? Was this test rig using your power supply that is in your machine?
 
i think i may have confused thinga sorry the gameboard i have intension of putting in the machine is fully tested on a test rig not with the cabs power supply

im scared of plugging that board in , so im using my other gameboard from my other si that also has a white screen and ive never played either ??
 
you reckon with the readings ive got at the edge connector and off my power supply im ok to plug the boards i know are working into the cab ?
 
done mod and ........nothing

done the reset line mod , and disconnected pin 6 as advised

and still the same feck all :(

not happy is a understatement :(

bridging pin one and 6 and then disconnecting the pin in the connector
all to no avail :(

look :



 
Last edited:
There is a switch on the coin door where the coin door lock is. When someone hits the coin door really hard it resets the machine. make sure that the contacts are not together.

what about the slam switch ?

please elaborate

thanks for your and everyones replies so far
 
Here is a picure of a midway coin door.

There is a switch on the coin door where the coin door lock is. When someone hits the coin door really hard it resets the machine. make sure that the contacts are not together.


http://www.google.com/imgres?imgurl...ch&um=1&hl=en&sa=N&gbv=2&tbm=isch&um=1&itbs=1

Anatomy-of-a-Midway-Coin-Door.jpg
 
You indicated that the Red cap that circled was only at 0.5 Volts.

If this is this correct replace. the cap.

Reset Modification? I assume you are talking to others on other on here or on other forums. Frankly trying many solutions at the same time will just mask the problem your board is having.

Check for power. Check the Crystal. Looking for physical damage on the board. Check if the CPU signals are there. Check for ram and ROM.

replacing the edge connector and doing a reset modification will just mask your problems. if you do not do them correctly.
 
yes the red measurment was taken on a old board , not the good one .

anyway got this issue now :

.

everything plugged in nice and tight .

even when all edge connectors off i get white screen so my contrast is too high but thats nowt .

but....

ive just checked voltages from psu without gameboard plugged in and the +5 is 6.95 ??

and i cant turn it down less than that but i can turn it up ??

?? whats going on ..

rich
 
took one of them tv multi games you plug direct into tv and used that and look what i got on moniter on machine



:) ..

happier now .

still need my gameboards testing again .
 
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