Fixing my Stargate Defender Reset Problem...

Jesse69

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I got kinda lucky buying a Stargate Defender for $330, - it was listed on ebay for $400 or Make Offer. The seller, Scott, said he'd take my offer of $330 and I drive from Chicago to Detroit to pick it up [$72 gas R/T]. When I got there by GPS to his house I only did a quick game test and the machine seemed fine. But later when I got it in my house it would reset on the game. I couldn't break 300,000 before it would reset.

Initially going through all the diagnostic tests it would say no ROM or RAM errors. The I won a ROM board on ebay [untested] for $20 and it worked fine but the Stargate still reset. Then I won another complete ebay Stargate PCB / Power Supply board set and I tested everything and I got another good ROM and Interface board. The main CPU Video board has bad RAM because on startup it says "book keeping error, close door to reset ram" or something. The spare sound board is faulty and doesn't produce all sounds "on the dot." So I'll have these spare boards repaired by the guy who advertises on ebay that he does Stargate PCB Repairs.

Now my initial original Stargate Main CPU / Video PCB RAM finally went bad. Funny how the game still runs on bad RAM. At startup it says "ALL Systems Go." But I did the RAM diagnostic test several times and got "RAM 35," "Ram 32," and "RAM 31" errors. What do these mean?

Just ordered 120 4116 RAM chips and can't wait to get them. Will replace all 24 RAMS on my original and spare MAIN PCB boards. Hopefully that fixes all the problems!

Oh, but after I clean my original Main PCB at all contacts with a wet tootbrush, and fixed a broken trace at the backside of the board with CircuitWriter - my game reset less even with bad RAM and I got a high score of 395,000 + 2 other 300,000+ games. So now there's no chance of chip shorting between pins due to corrosion or dirty contacts.

In the end, I want a perfect running Stargate so I can break a million on it. I broke a million in Defender back in the 80's but not on Stargate. Stargate would just suck up my quarters.

But I cheat a little on my Stargate - I set Inviso to 2 sec per ship rather than the std 1 sec per ship.

And the seller Scott put a switching power supply in it and I found the best voltage to set the +5V was at +5.41V so the main board gets +5.33V and the Rom board get +5.25V. Seems to reset less at that voltage.

Any comments or advice?
 
I now just messed up my original MAIN PCB by trying to check the voltage of a 4116. Now just RAM garbage on boot and no "ALL Systems Go" message. I hope replacing the tested 4116 - maybe fried - fixes this worse problem.
 
Comments: Wow, where to start?

Advice: Again Wow, where to start?

There is nothing wrong with a boardset that comes up with the audit feature. It means that the batteries are dead, removed, or corroded. Sending your boards off to the guy on eBay who "claims" to fix them is a HUGE waste of your money and time.

Your reset problem is most likely a power supply issue.

Setting your power supply to 5.4 will cause more damage than any amount of good it will do.

Just my $0.02
 
I've read that you can damage chips at 5.5v, you're a bit too high on your 5v for comfort. Bad RAM can cause a lot of different problems, including resets, so replace them all first and see if it's fixed. Before sending out your non-working sound board, make sure its jumpers are set properly. That board was used in a lot of games, and many of them used different jumper settings. See this page for info: http://www.robotron-2084.co.uk/techwilliamshardwareidsound.html
 
Our Robotron kept resetting and it was one of the fuses was loose. Just pinched the fuse holder a little and it hasn't reset since.
 
There are a number of reasons that Stargates will have a RAM error, continue and then reset later. Just replacing the RAM may not catch them all.

I do Williams board repair a lot cheaper than the EPay guy. If I can't fix it, I usually have a working replacement board on hand. It is also possible that you are having power supply issues. Switching power supplies and Williams boards don't mix well (see rant in other threads). If you have the original power brick (transformer, line filter and fuse) I can sell you a working replacement or rebuild the original power supply board if your seller left it in there.

ken
 
I read a Williams pdf manual and it says the voltage should be up to 5.2 V at the boards, so I lowered the switcher until the board pins read 5.2 V.

Now I have two unworking main PCBs. I'm not an electrical technician but I'm smart enough to get a Mechanical Engineering degree. If I bought a logic analyser to find bad chips, how and where do I buy replacement chips or how do you source alternate equivalent replacement chips?

Plus soldering and removing / replacing chips on a circuit board - I don't have the tools.

I just put in new batteries at 1.54V each in the spare board and it gets the booking error. It resets on gameplay and the high score table is full of garbage. It locks up on the Factory Settings page.

1 board is a R8948 revision board and the other one is a R8731 (Revision B) board [fried at the 4116]. From http://www.robotron-2084.co.uk/techwilliamshardwareidcpu.html

This logic analyzer would be nice to get, but I don't know how hard it is to replace chips or where to source them.
http://www.hobbylab.us/default.aspx?lead=GoogleCheckout
 
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I do Williams board repair a lot cheaper than the EPay guy. If I can't fix it, I usually have a working replacement board on hand. It is also possible that you are having power supply issues. Switching power supplies and Williams boards don't mix well (see rant in other threads). If you have the original power brick (transformer, line filter and fuse) I can sell you a working replacement or rebuild the original power supply board if your seller left it in there.

ken

My PS plugs were messed up with the switcher conversion.

If you really do Stargate Board repairs you'll have fun fixing up my most messed up board. Initially it ran fine only with a reset problem. Then finally the RAM went bad, and now I shorted a 4116 and possibly did worse damage to the board, such that on boot up it only stays at the RAM garbage screen and doesn't go to the "ALL Systems Go" screen. It is a R8731 (Revision B) CPU Board. So how would you fix it and how much would you charge?

Do you fix Stargate Boards as a side business or hobby?

How much would you sell a working Stargate Main CPU / Video PCB?
 
There are basically 3 sections to this or any other game. 1 monitor, 2 boardset, 3 power. They are not in any specific order, and you need 2 of them to be known good before you can acurately diagnose the other one. Sounds like you have a good monitor at this point. I would verify your power section next.

If you need board repair on a Williams you can't go wrong with YellowDog. Saltbreez also does Williams board repairs. You will get much better results from either of these KLOVers than you will with the guy from eBay.
 
Dokert, thanks for the vote of confidence.

I do board repairs on the side to fund the addiction, I mean, hobby. So I have a little lower overhead then the places that are charging to pay the rent.

Trust me, a fried RAM is nothing that a chip puller and a replacement can't fix. I have seen some truely nasty hacks <shudders>. With Stargate there is a small 7 segment LED on the ROM board. What you should be seeing on there is a set of three numbers blinking that probably point at the RAM you crisped. The numbers should be a 1 followed by a 1, 2 or 3 and a number from 1 to 8. This indicates RAM error (1), the bank (1, 2 or 3) and the chip (1 - 8) that was the first one to have an error.

The other issues sound like a potentially bad CMOS chip or the battery holder may not be working correctly. Corrosion on the contacts is very common. I normally replace those with a lithium button battery (CR3232). I charge $5 for that mod + the price of the battery, or you can supply it when the board is returned.

One piece of CMOS trivia for you is that on Williams games, the CMOS is devided into two sections. The first section contains the high score table and the settings. The second section is bookkeeping data. The second section is protected by the memory protect switch located on the left side the coin door, which is why you need to open the coin door to reset the bookkeeping totals. On correctly wired Williams cabinets there is a second switch located in the top of the coin box that can be accessed when the coin box door is opened. This was to allow someone on site to collect money and adjust game settings, but not to reset the bookkeeping totals. This is why the locksets are keyed differently. The onsite operator could open the coin box door only. The route operator could open the coin door and the back of the machine.

I think a logic analyzer is overkill until you get some hands on experience with these boards. You would be much better off with a logic probe and the schematics at first. Make sure you get one with audio feedback. You'll appreciate being able to hear the states change when you are looking at the schematics at the same time.

Parts can be obtained from a number of places. I tend to use Great Plains Electronics www.greatplainselectronics.com). Ed runs it and is a member here (GPE). I also use Jameco (www.jameco.com) for odds and ends and things Ed doesn't carry. For more exotic (read obsolete) arcade parts, well that is the fun part of this hobby, trying to source impossible to find parts.

As to my fees for repairing, I normally charge $20 + parts + return shipping per board and if there is nothing wrong with the board I rebate $10. For Williams CPU boards I normally charge $50 + shipping. For sound boards it's $40 + shipping. For more than 1 board I try to combine shipping as much as possible.

ken
 
Yellowdog - I looked at your VAPS Profile and it says you worked at Williams Electronics! What did you do there? I guess I would send my Stargate Board to a guy who once worked there! And it's nice to know you got a Defender and Stargate machine to test my boards on.

But have you fixed nasty Stargate Reset problems? How long would it take you to fix my 2 boards + 1 sound board and how do I pay you? Refurbish the boards by replacing any bad diodes, capacitors, and resistors too... And one MAIN PCB board has a smashed Decoder ROM chip - would you be able to replace this with a new burned EPROM? I don't know if this smashed Decoder ROM chip is working 100% with good pin contacts.

I guess I'd contact you at - [email protected] ?

And you live in Houston, right? I once lived in Houston working for Schlumberger and then Jacobs ESCG [NASA work]. Houston is a great place to live and I miss that place. I'd rather live there than Chicago, and I miss eating at Jack in the Box and Waffle House.

I have 2 MAIN PCBS - 2 x $50 = $100
2 Lithium Battery Mods = + $10
I spare sound board that works but it doesn't give proper sounds at times sometimes the sound is wrong - how much would this cost?
The thing about the Ebay Repair guy is that he has variable costs for repair of a working PCB - up to $65.
All my ROM and interface boards are good but I'd send you a set so you can test it with my boards.

I'm just waiting to get my 4116's to see if replacing all these 24 chips per MAIN pcb will get them working. My ROM board didn't flash any numbers indicating a BAD RAM chip. I only get RAM 35, 32, 31, and 21 errors from the monitor screen.

I'm also gonna get and plop in new 6809E CPU's to see if that fixes my boards. http://www.jameco.com/webapp/wcs/st...&pa=43545&productId=43545&keyCode=WSF&cid=GMC
 
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Hi Jesse.

My repair fees are $20 per board for the CPU, ROM and Sound boards (I only charge $10 for I/O boards) + the cost of parts + the return postage. If there are parts that need to be replaced I will contact you with a list of the parts and the cost. You make the call on doing the repairs. Unlike some places that just hit you up with a big bill at the end, you are always in control. If I find that I cannot repair the board, I will make an offer for a board swap with a known working board out of my stock of parts. With CPU boards I always swap with equivalent or greater (i.e. if you send a Rev B board and I don't have one on hand, I will swap with a Rev C or D board).

So in your case, the repairs would be $20 x 2 boards + parts + return shipping. I don't keep a stock of decoder chips on hand, but I have a couple of sources to get replacements. If you want to send the sound board along, that would add an additional $20 + parts and shipping would be bundled with the other 2 boards. Plus an additional $5x2 for the lithium battery mod.

I also do special requests. Since you have already ordered RAM, if you want to send enough to repopulate the boards (24 per), I will install it and test it while checking the boards over for other issues. That would be covered at no charge.
The $50 previously quoted is for purchase of CPU boards without swap or trade-in.

It is also good to send the complete set of boards (CPU, ROM, sound & IO boards) along if possible. That way I would be able to minimize the chance that there would be a hidden problem between the boards.

I have fixed a number of board issues including bad crystals, defective RAM, socket problems, watchdog circuit issues, dead CPU's, address bus issues, bad CMOS, broken connectors, and more things than I can think of right now.

You can contact me at my email address ([email protected]) or you can use the private message facility here on the KLOV board. If you haven't used it before, just click on my name in the header of the message and a popup menu will appear. One of the selections is to send a private message. Just click on that selection and follow the prompts.

I usually take Paypal for repairs (instant gratification is a wonderful thing :)). Normally I ask for payment once the repairs are complete and the boards are ready to be shipped back. That way you know what the total is going to be and you are not getting nickeled and dimed.

I worked in Chicago for various companies for 14 years, spent 8 years in Denver and now have been in Houston for almost 10 years. I love Chicago (except in winter), I loved Denver during ski season and I enjoy Houston in the spring and fall when it is not too hot. So if I ever win the lottery, I am going to need 3 houses I guess :D.

Save your money on buying new CPU's. Putting a new CPU in will not fix the RAM issues you are having.

ken
 
Wow Yellowdog - you really got awesome repair prices! You must be doing repairs more for the thrill of getting something fixed than for the money! What do you do for a living? Are you an electronic engineer? What's your real name? What did you do when you worked at Williams?

I'm thinking about sending you my 2 complete Stargate board sets; - swap my bad resetting Rev A board for a Rev D board that has a Lithium mod. See if my good boards work with a REV D board. Fix my shot Rev B board and 1 bad sound board. So send me back quickly a swapped Rev D board with a complete working board set back while you work on my bad Rev B board and soundboard. Unless you fix these in no time due to expertise, experience, and knowledge! - Will that work out for you? I'll pay for shipping twice. I'll pay you extra to refurbish my REV B board with new capacitors and diodes if the old ones are bad, but I was thinking about doing this refurbishing myself but I know nothing about how to test diodes and capacitors. Then where to source equivalent parts.

I wanna replace all my 4116s before I send the boards to you. Ultimately, in the end, I want 100% working Stargate board sets that don't reset so I can break a million in Stargate which I never did.

My real name is Jesse E. and I'm an unemployed Mechanical Engineer suffering through my 75th week of unemployment.

I was thinking about having some fun fixing these boards myself but I'm not an electronic technician and I know nothing about or have the soldering tools to remove and install I.C. chips. What kinda soldering tools do you have for working on chips and how much do they cost? Do you analyze with a logic analyzer too? I was thinking about getting this too - http://www.hobbylab.us/default.aspx?lead=GoogleCheckout It seems nasty work replacing an I.C. chip unless you got good tools to desolder, vacuum, and resolder IC's.

This place seems to be the cheapest place to get IC chips for Stargate and Defender. I feel like getting 6809E CPUS from them! http://unicornelectronics.com/prod.htm
 
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Welcome to the addiction, may I suggest that if complete stability is what you are after, you pay Dokert for a complete wire harness, rip out an replace the one you have?

Have Ken rebuild/sell you a linear supply, and replace the 4116 RAM with 4164 RAM.

Just my $0.02 worth.

Saltbreez
 
Wow. Jesse slow down a little or you will be a broke unemployed mechanical engineer.

Based on your descriptions, it will probably take a couple of days to fix the issues you've described and get your boards stable.

My prices are low because,
(a) this is a hobby and I am trying to give back to the community,
(b) I don't have a storefront and employees so there is not much overhead
(c) I have a regular job so the money I make repairing boards funds the addiction and goes back into restoring games.

I have a known working Stargate board set that I was about to put on Ebay. We can work something out for a board swap. I normally start the auctions at $100 for a 3 board set (CPU, ROM and I/O boards) or $140 if I throw a sound board in. I'll need to find a working sound board. I've got a box of them waiting for some testing and just got another box to test yesterday. So I am pretty sure I can find a working one.

Don't waste your money on the hobbylabs scope. It looks like it might be an interesting tool if you understand what you are looking at. I normally just use a $20 logic probe made by Meterman (LP25a). It does the job and lets me walk the circuits and find what I need to know. I have a 100MHz scope, but to be honest I haven't even plugged it in lately. The logic probe is so much smaller and handier.

There is a syndrome that occurs when people first get into this hobby where they try to buy everything all at once. I'm guilty of doing it too. Just take a little advice and go slow. Think about what you really need before you run off. It will save you money, time and a lot of storage space later.

For just the price of that scope, I can sell and ship you a complete known working 4 board set (CPU, ROM, I/O and Sound boards). If you buy the scope you won't be any closer to fixing your board problems because yo will still be learning what a goog board looks like vs. a bad board set. I got lucky when I started. I got one complete boardset out of 3 EPay "working, but untested" boardset auctions. From the working boardset I was bae to repair the other two boardsets. One is now in my Robotron, one is in my first Joust and the original set I got working is in my Bubbles.

It's up to you. You can buy the scope and try to fix your boards. Hopefully you won't fry any more chips. Or I can sell you a known working board set, give you return credit when your broken board set gets here and if you ship both board sets I can give you a quote on fixing the least damages boardset and get that one back to you once it is fixed. That way you can have a working boards set in a couple of days. And a backup set once they are repaired. I normally give 50% trade in credit unless it is either unfixable of severely hacked. So by the time shipping is factored in, for about the price of the scope you can have a known working boardset and a working rebuilt board set.

But, it's your boards, your decision and your money.

I know, I am a lousy salesman.

ken
 
Yellowdog - I guess what I'll do is have you fix my two bad Main Stargate PCBs and 1 bad sound board. So then I'll have 2 complete Stargate Board sets working after all repairs. I was willing to buy a Rev D Stargate Main PCB board or swap this with my Rev A board, but I don't need a complete 3rd Stargate Board set.

Do you have a complete 100% working [No Resets] Defender Board set to sell too?

How many Stargate Main PCB boards do you have that work 100% no resets? What Rev are they?
 
The Stargate CPU boards are the R8948 (Rev -) boards. I think I have 1 working right now, but I just picked up a couple of others this weekend that I need to test. But Stargate will run on all 4 versions of R8731 (Rev B, Rev C & Rev D) boards as well as R8948 (Rev -) boards. Robotron, Joust, etc. will only run on R8731 boards. So it really depends on how many R8948 and R8731 boards I have. I know I have 3 or 4 working R8731s. There may be more hiding in one of the boxes on the shelf.

I will need to see what I have in working Defender board sets right now. I know I have a couple that I got as trade-ins a while ago that I will need to look at. Defender sets are not as popular as Stargate or Joust sets, so I usually don't bother looking at them until someone is interested.

ken
 
Yellowdog - are you capable of replacing the ROM chips or burning a replacement EPROM for a bad ROM? My Stargate REV A board has a smashed ROM that has severely bent pins - I either need a replacement ROM or EPROM for that.

I'm not an expert at sound card diagnosis, but I looked at the Williams Sound & Speech pdf and I'm guessing my Sound ROM is bad. So where do you get replacement ROMs or do you just burn a replacement EPROM? Also, I think my electrolytic capacitors are off spec so maybe that whats screwing the sound too.

As for my Defender, I hardly play it that much and I play Stargate more. Gimme a quick quote for a complete Defender boardset because I might buy a sound board and interface board from ebay soon.
 
I can burn everything except the Decoder ROMS. Those are the two ROMS on the CPU board. I have sources to get replacements, so that isn't an issue. My burner just can't burn the very specific BiPolar ROMS they used for the Decoder ROMS.

If it is smashed badly enough a new socket may be necessary as well. Those aren't hard to do, just time consuming. You need to be careful to desolder them correctly so they don't mess up the circuit board traces before removing the old socket.

The sound card ROMS are either 2716 or 2732s which are not hard to burn. It depends on how the card is strapped. If you have bad caps on there it will affect the voltage provided to the board (it has it's own DC rectification circuit built in. that's why it can use the 12V unregulated as it's input).

I'll check and see what I have in running Defender parts when I get home tonight and send you a PM.

ken
 
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