Space Invaders Restore- A Beginner's Journey

[noahstauff]

Dear Arcade Controls Fourm members,

I have just obtained a non-working Midway space invaders arcade game. I am really trying to get it back into working order, but sadly I have but a little electronics knowledge. It also does not help that when I search Google that I cannot find hardly any restoration info on the machine, let alone anything directly applicable to my scenario. Any ways here's the deal. I tested the power supply board for voltages, and all but the -5 volts seems fine. The -5 v is reading like 200mV which cannot be correct. I ordered a Cap kit for the Monitor and the Power Supply from Bob Roberts, as well as a new power cord. After the new caps are installed in the power board there is no change on the -5 v but everything else is spot on, well the +18 is reading 17.20 but that's fine. I then proceeded to install a new voltage regulator that is in the -5 v circuit, a 7905C. After the part is installed, there was still no change. I really need to get this sorted out before I even begin to look at the monitor, but the monitor is currently just showing a solid grey screen. On the power supply board there are a few parts that look to have gotten hot in the past, but I need to know their function and if they even effect the -5 v circuit. Could some one please tell me what parts do what, how they can fail, what problems they cause when they do? I believe this information would not only be helpful to me, but also to other beginners. I do know what caps and resistor are, I am talking about the green diode looking things, the round metal things with 8 legs that stand off the board, the disc thing in the middle of the heat sync, that sort of stuff. I think it would also be helpful to have a part diagram that maybe displays the value of the resistors on the board as well if anyone could possibly provide one? One last thing, I connected the monitor up to a kind of home-built test rig, does anyone know the correct plugs for the monitor wires that go to the tube (not the ones that connect to the neck) there are 4 a black one, red, green, and yellow.

I will post a link where I have taken pictures of the board along with other things to do with the machine, I am really looking forward to getting this working.

Thanks in advance,

Noah

Pics: https://skydrive.live.com/redir?resid=DB065D31B19F9386!925&authkey=!AGvSaE7JToCTVJ4

P.S. I was not impressed with the kit provided by Bob Roberts, The pics tell the whole story....

P.S.S. If this thread it not in the correct place/ I have done something wrong please tell me so that I can fix it. I am really looking forward to becoming a member of this great community.

[noahstauff]

Here are some pictures of the board that has the parts I need help identifying:


In this picture you can see a charred resistor next to the metal can thing... It tested fine however.


In this picture you can see a replaced 7905C voltage regulator, its replacement had no effect on the -5 v.


This is just a picture of the middle of the board, hopefully as I stated in my original post someone could help me identify the parts that were specific to these machines, what they are, how they fail, what problems they can cause when they do, etc. I believe this info could be very helpful to both me and other beginners in this field.


This picture shows some thick leaded green things that appear to have gotten quite hot in the past. What are they? Are they diodes? How can I test them?


This picture is just a general overview of the board, along with close ups on the Caps. I said I was slighty dissatisfied with Bob's cap kit mainly because the replacement caps are radial while the originals were axial, as well as being slightly of higher value. This was not mentioned on Bob's site. Also I have a picture in the album I posted a link to showing that the supplied zip ties are only 3 times too big to fit though the holes in the board. I'm sure all the parts work, but I guess I was just expecting for the cap kit to be you know.. for the board it says it is for I guess?

Sorry about not posting the pics directly, I am still trying to figure out the best way to do that.

Sorry about not replying sooner, I've been quite busy lately. Also I apologize for the large size of the pictures, I can correct that if need be.

Thanks in advance,
Noah

[Spyridon]

What was the problem with the Bob Roberts kit?

Post the specific photos you have questions on directly into this thread. It will make it much easier to respond to.

[ed12]

this should help u
go to mikesarcade
the place has a boat load of manual etc
d/l what u need

ed

[noahstauff]

Fixed above pictures.

Here are some pictures of the monitor:





Sorry about the bad angle, but I would like to know if anyone knows the correct places for each of the four wires to connect the the monitor tube? The ones that are not in the neck connector. There is a black, red, yellow, and green wire. I have reattached them the best I could form those pictures, but I'd just like to be sure they are in the correct places.

Thanks again,
Noah

[noahstauff]

Really? Its been about what, two weeks now and no replies? Are you seriously telling me that no one on these fourms can tell me why possibly my -5 volts is missing or at least give me some advice? I would also like to know some info on the metal 8 leg transistors and such that were used in this era, like how they fail and what to expect when they do, how to test them even.


Thanks,
Noah

Oh and.. Bump...?

[BC_Jeffro]

hi there i have a S/I Deluxe and the same power supply, mine has good +5/-5 but the +12v is at 21.3v the adj pot dose nothing and my reset voltage is at 4v and dose not go down to .5v I have replaced all the caps on the board and re-soldered the connection area
thanks

[spystyle]

Did you k guys know about this ?

http://cambridgearcade.dyndns.org/?q=node/15

You can use an ATX PSU in your Space Invaders, as long as the PSU has -5v

[orion]

Did you k guys know about this ?

http://cambridgearcade.dyndns.org/?q=node/15

You can use an ATX PSU in your Space Invaders, as long as the PSU has -5v

That site is for a guy over at KLOV. I just bought his 6pac, which is great. He shipped it out the same day I paid for it and all was well and I am quite happy. The only issue is that he seems to only produce kits and parts off and on. I emailed him about his six pac and got a reply almost a full year later.

[samelak]

Did you k guys know about this ?

http://cambridgearcade.dyndns.org/?q=node/15

You can use an ATX PSU in your Space Invaders, as long as the PSU has -5v

I tried contacting cambridgearcade twice this year for this and never received a reply. My Space Invaders is in desparate need of electrical repair. I've already had the board gone through (twice) and now the monitor isn't working. Before it would "ghost: really bad, but now its blank. I want to mondernize the electrical as much as possible while still using the original PCBs for gameplay. I figured the first step was to use a modern ATX PSU. Does anyone have a way of contacting cambridgearcade outside of their website? Also, has anyone done the color monitor conversion in a Space Invaders? I found a tutorial. I think my last resort will be to pull everything electrical out of the cab and go with a JAMMA set-up with a 60-in-1 board set just for Space Invaders and wire a color monitor to reverse the picture so it display right with the cabinet display mirror. I would hate to do this because I have original boards that are working.

[spystyle]

Regarding the ATX 8080 adapter. I had trouble ordering one on the website, the web form couldn't calculate postage to my shipping address (?). So I decided to contact the guy directly.

Here are some good leads.

e-mail :

CambridgeArcade at gmail dot com

On eBay :

http://www.ebay.com/usr/mspaeth

On KLOV forums :

http://forums.arcade-museum.com/member.php?u=32474

His name is Mark Spaeth, he lives in Cambridge Massachusetts, and owns Cambridge Arcade Repair. (Apparently)

And I think this is the Facebook page for that :

https://www.facebook.com/pages/Cambridge-Arcade-Repair/133216276726274

So with all this information we should be able to contact him LOL.

I actually need an ATX 8080 adapter myself.

Cheers,
Craig

[spystyle]

Well I was able to communicate with Mark via e-mail. CambridgeArcade at gmail dot com

And I was able to pay for two ATX 8080 adapters.

The new type of adapters don't require an ATX power supply to have a negative 5 volt wire. Here is what he wrote about that :

"The old ones require an older ATX supply with a -5V line, and the newer ones have a -5V regulator build in and will work with any ATX supply.  (24-pin atx will just have 4 pins hanging off the end)."

So it was $37.50 each plus $6 shipping. Payment through PayPal.

So I guess it is possible to communicate with Mark Spaeth LOL

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Update :

OK I received two adapters I only reside about 3 hours drive from Mark, and he must have dropped it in the mail right away, because I received the adapters only one day after I paid.

Now I just need to figure out how to use them LOL.