Stargate blowing IO ic chips.

[Spunky_Bruiser]

Ok so where to begin,.. First this stargate looked to be hacked to pieces,.. It is in a defender cabinet, on a sinistar board, looked like defender Io board, and running stargate. I do not know, but apparently it worked flawlessly at some point.

So the guy I am helping out had a tech who did some work for him but was let go and so I sort of came into this mid way through so to speak. Thrust is always stuck on right now. The old tech and I then both tracked it down the middle IC chip in the IO board. The chip is now obsolete, so I picked up a new CD4049UBEX chip, put in a new socket (thankfully) and the chip in the socket. I also reflowed the socket pins as they looked to have some cold joints starting to form.

Turned that puppy on and OMG the ship was not stuck on thrust. It worked great and was playable. Went through a game, went through another game and as soon as the third game started ,... The thrust was stuck on again. I reseated the chip and turned it off and on and stick stuck on thrust. I smelled around the IC board and had a slight electric smell but nothing like a shorting power supply or the like. Just mild smell. I am not sure. I have one more CD4049UBEX I can try in there but have a feeling after 5 mins I will be back to a stuck thrust.

Looking back I should have went off my check list and checked the power supply first. Out side of that I am not too sure what else to do or try. I did pick up a stargate board from e bay and that did nothing. I thought it was a stargate board not a sinistar if that makes any difference. I changed the cap on the IO board. Any other suggestions I would be all ears.

 

[mecha]

change the ribbon cable next. it might have something shorting. they fail kinda weird. the Sinistar at my work started popping 4049 chips and I was able to source those in bulk so after replacing all of them, knock on wood, it's still held up.

Rev. - through Rev. D boards are all compatible with Stargate, the one minor exception being Rev. - ONLY runs Stargate, while B-D are capable of running the Special Chip games (Robotron, Joust, Sinistar) along with Stargate. the Rev. - is the board that has the small board plugged in with the yellow and white wires coming off it, if that's the one you got off ebay.

if you would much rather just have everything gone through let me know and we can make arrangements to send them to me. otherwise if you don't care about matching serials and the like, I have spares of just about everything for Stargate.

last note, a Defender input board will work, you'll just have to rewire the plugs going into it. Defender's board had the ground on a completely different pin and I think the rest of the inputs are literally backwards. LOL I really need to put all of that into a spreadsheet for future reference.

 

[Spunky_Bruiser]

Oh my the ribbon cable,... I was looking at that thing and going,... How the heck do you take this thing off if you wanted to... let alone find a replacement.

I am not 100% sure about the stargate Io board but I it looks like the ribbon cable had a red line on the one end of it and the guy said it was good for all of those games.

I would have to talk to Jerry about what he wants to do about the board. If I can fix it, that would be awesome, but I know at some point he does want a Defender set. Stinks too, I almost picked one up for 100 bucks (untested but most likely working) but I did not read his response to call him back until I was too late by 10 minutes. Ya know, I did not check to reflow the ribbon cable connector on the main board I will have to take a look at.

Seems like after he opened the arcade his monitors have been going down so I only work on this Stargate for a bit before I start work fixing his monitors. People are always asking when it will be back up though. Heck most people think the game is Defender lol

 

[tendril]

Run the board with that chip removed from the socket, and use a probe/voltmeter on all pins of the socket and make sure it's what you expect. What I'm thinking is maybe you have your 5V supply voltage shorted to somewhere it shouldn't be like an input or output.

 

[toledoflyer]

Run the board with that chip removed from the socket, and use a probe/voltmeter on all pins of the socket and make sure it's what you expect. What I'm thinking is maybe you have your 5V supply voltage shorted to somewhere it shouldn't be like an input or output.

^^^ This, but I would add while measuring each pin have another person press all the buttons and move the joystick. You may only be getting a bad voltage when a switch is closed. 5V isn't a problem since it's a 5V IC but if you get MORE than 5V like 12 OR if you see a negative voltage at any time this would be your issue. Figure out what combination is giving you the bad voltage then trace it down in the wiring.

ALSO-
That part is a CMOS IC which ARE static sensitive. The widget board has some caps and resistors which help to absorb any ESD discharges but the grounding to the board AND to the CP is needed to make the protection work properly. (It provides a low resistance discharge path for ESD events)

 

[mecha]

^^^ This, but I would add while measuring each pin have another person press all the buttons and move the joystick. You may only be getting a bad voltage when a switch is closed. 5V isn't a problem since it's a 5V IC but if you get MORE than 5V like 12 OR if you see a negative voltage at any time this would be your issue. Figure out what combination is giving you the bad voltage then trace it down in the wiring.

ALSO-
That part is a CMOS IC which ARE static sensitive. The widget board has some caps and resistors which help to absorb any ESD discharges but the grounding to the board AND to the CP is needed to make the protection work properly. (It provides a low resistance discharge path for ESD events)

gamefixer and I talked about this with that Sinistar, that something in the control panel was probably zapping it. be it a ground thing or something to do with the lights. but I tried it last night and all my opto directions are still good... so here's hoping.

the +12 and -5 voltages don't go over there at all, they only run to the ram section. if that was indeed an issue they would have dead rams too.

the ribbon cable will need to be desoldered off, and replacements can be found at QuarterArcade. check to make sure the pins where the input board plugs in aren't bent. I'm sure you would've immediately noticed the difference if they were, but look anyway. I commonly find them bent when I get repair boards in.

you can identify a Defender input board vs. the Stargate/later ones by presence of key pins being removed. Defender had the missing key pins, while the others were all populated with pins.

something to try, it's my torture test, put the game in test mode and advance to the input test, press on the input ribbon cable. if the game starts blipping and blooping, the cable is bad. you can do this with the suspect 4049 chip out, as there are other inputs that will register too. if that's then the case, I can tell you what to do next as far as replacing the ribbon.

 

[Spunky_Bruiser]

Thanks everyone for the help. I appreciate it. If I leave work early tonight I will head over to the arcade and test out the voltage and test method ALONG with having the board screwed in to fully ground it and not leave it hanging lol. I will try my last IC after and if that blows I will pick up a new cable and chip from QA.

Thanks for the direction everyone.

 

[mecha]

it's grounded through the ribbon anyway, but you also don't want other not-ground parts smacking the metal. yeah