space invaders midway in a taito cab help

baz

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hi everyone im baz from australia.

finally after 20 years i decided i should once again own a spacey machine lol

scooped one off ebay...

here the short story...

keeps blowing 5 AMP fuse...which is located next to the transformer...

there is 4 fuses in total.. its the last being the closes to the transformer..

keep in mind this is a taito cabinet and not the midway.

all voltages ok.. +5 -5 +12

i disconnected everything.. fuse doesnt blow.. hooked back up monitor and fuse still ok.

yes as soon as i hook up the pcb the fuse blows :(

here is what i dont understand.. the fuse that keeps blowing.. i traced it back to the power supply board as ground....

by the way the monitor is showing wavey verticle lines.. even when the board isnt plugged in.. is this even normal for a black and white monitor?

any spacey techs or restorers who have gone through the technical issues your help is deeply appreciated.

ps i can supply pics if i need to.
 
another thing.

also the board is fine and works on another machine.. well thats what the seller told me..

i can kinda confirm this as i can hear the invaders thump and fire if i shoot... but thats before the fuse keeps blowing...

i have approx 60 seconds before the fuse blows when i turn it on.

im a bit lost as to whats causing this 5 amp fuse to blow.

and yeah i checked the tilt switch.. she is fine and not touching.
 
by the way the monitor is showing wavey verticle lines.. even when the board isnt plugged in.. is this even normal for a black and white monitor?

Can't answer your fuse issue (though I would guess a rogue wire somewhere in there is causing it) but no, it is not normal. That's the same thing that happened to my Dig Dug and DK Jr. cabs when the caps on the power supply started to die. I'm not sure if it's the cap on the monitor or the power supply, but in my experience the wavy verticals come from the power supply itself (it always seems to be a different set of symptoms when it's the monitor, at least in my limited experience).
 
why my space invaders has lines on the screen ?

finally resoleved the fuse blowing issue.

now got sound.. the thump thump.. credit works... buttons etc.

but the screen is wavey with lines...

what would this be ?

is there a horizontal adjust on raster screens like rgb monitors or is this clearly a fault ?

http://img251.imageshack.us/img251/8669/p1010011u.jpg
 
this is what im now seeing..

this is what im now seeing...

just rows of lines...

p1010001nd.jpg


anyone experienced this before ?
 
I would say it is a monitor issue,but to be sure.Space invaders puts out composite video,so you can unplug the connector from the monitor chassis and rig an rca cable into the video lines.Should be a shielded type,white center wire with ground wrapped around it and black covering.Find those 2 pins and stick your wires from rca jack in there and plug into tv.This will at least verify the boardset is doing everything it should be.
Be careful you get the right wires,trace them up from the pcb edge connector if need be.
good luck
 
oh shit.. i dont have a crt type tv in the house.....

you mean i can actually display space invaders video out onto a old tv ?

or are we doing this to verify a signal ?

as far as i know from the person i brought this machine from the board worked fine in another space invaders machine..

so it must be either a monitor issue ?
 
I've not messed with the B&W monitors, but on a color monitor it would be the screen control turned up too high.
 
i have tried all the knobs on the chasis board , even with the 2 video wires disconnected from main board im still getting the 2 lines.. even with the brightness dimmed so low i can just see it
 
question...

what should the voltage output of the video and ground output from the board to the monitor be ?

also what should the black and white raster screen be displaying if the video signal is not hooked up ?

im still trying to troubleshoot to know where the problem is coming from....

also my 5 volt rail says 5.84 and my 12 volt is 12.34 is this ok for space invaders ?
 
today i noticed it doesnt matter if the video signal from the gameboard is connected or not.. im still seeing the same screen...

i have tried all the pots for adjustment on the chassis...

im stuck on what to look for next...
 
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