Defender help

WingKing

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A little background info: I'll just preface this post by saying that I've never worked on Williams games before. I don't have a ton of knowledge in this area, but I can follow instructions if you can explain to me what I need to do. I have read through a lot of older posts on Defender repairs and looked through the manual.

I purchased 3 project Defender cabs not too long ago and I'm just getting around to consolidating all the working parts into one cab. I have 3 complete board sets. Only 1 monitor is working.

I've swapped out different boards and trying different combinations of things and so far I'm not having any luck. I'm starting to think that maybe I don't have 1 fully working set of pcbs among the 3 sets I was given. Or maybe the wiring in the cab I'm using is shot.

Issue: When I power the game on I hear the sound that I believe you're supposed to hear. The monitor is turns on and displays a white/gray color and has some rolling (I think it might also turn to a reddish color after a while). The game does not coin up or play blind. The power supply has the +5v +12v and -5v lights lit up. All 4 lights on the ROM pcb stay lit. I can do a test of the sounds and adjust the volume.

Here is where my inexperience comes into play. I'm trying to test voltages, but I can't figure out where/how to do it. I found the location of all the voltages in the manual. If I stick the leads of my multi-meter down into the openings on the connector, it doesn't make contact or get a good enough connection to read anything due to the way the wires are inserted into the connectors. Is there somewhere else I should be testing voltages? If so, could someone please give instructions on where to do it in the most plain way possible?
 
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Actually just read up and learned how to test the +5v on ROM chips. Learning a lot with this one. Pretty cool :) I'll test it on the board when I get home from work today.
 
I include how to test at chips in my PSU guide (which needs a rewrite soon) ... there's a number of factors that can cause voltage to drop on these though and if the rams in particular don't get enough power, the game won't run. the 4116 ram is tri-voltage, requires +5, +12, and -5. lots of people immediately think they need to test at the rams, and of course this is the most accurate way to do so, but they also undoubtedly always slip and touch the +12 to the next pin over and not only does that nuke all the ram, it'll spread to the bank controllers as well, and maybe the 74153 multiplexers too... I've never actually done it myself. :)

people also think automatically dropping a switcher in because you have the functionality of adjusting the +5 will be a gamechanger too. it isn't, because you're only correcting half of the problem in the event that voltages on the MPU are low.

I provide the service to fix the power supply, MPU, and rom boards to fix this. regardless if you wish to fix it yourself or not, drop me a PM for more help.
 
I'll also add from personal observation that the voltage on the eprom board may differ from the MPU board (+5V).

If you have the ability don't set the power on the RAM to +5V and ignore the voltage on the eprom board.... it could be higher. Remember on Joust, Robotron, Sinistar, Bubble, Splat! (others?) have special chips on the EPROM board. You don't want to risk stressing/killing those.

TTL doesn't need 5V exactly. Some board are finicky as well, and like a bit less or a bit more than 5V. But standard TTL power requirement is 4.75 to 5.25. If I've got 4.75 at the chips, I don't fight to get that to 5 as a general rule.

The game here is Defender, so there isn't anything special on the EPROM board (other tha a 6821 PIA if you want to call that special :) ).

Just wanted to bring up due to harnesses, connections, solder joints, etc the voltage can differ on these boards. If it differs significantly the cause needs to be determined.
 
I include how to test at chips in my PSU guide (which needs a rewrite soon) ... there's a number of factors that can cause voltage to drop on these though and if the rams in particular don't get enough power, the game won't run. the 4116 ram is tri-voltage, requires +5, +12, and -5. lots of people immediately think they need to test at the rams, and of course this is the most accurate way to do so, but they also undoubtedly always slip and touch the +12 to the next pin over and not only does that nuke all the ram, it'll spread to the bank controllers as well, and maybe the 74153 multiplexers too... I've never actually done it myself. :)

people also think automatically dropping a switcher in because you have the functionality of adjusting the +5 will be a gamechanger too. it isn't, because you're only correcting half of the problem in the event that voltages on the MPU are low.

I provide the service to fix the power supply, MPU, and rom boards to fix this. regardless if you wish to fix it yourself or not, drop me a PM for more help.


Thanks, Mecha. I appreciate it. I almost just sent you a PM asking for help instead of making this post. I saw you were very helpful in a lot of the older Defender help threads out there. I did read through your guide and it was very useful in getting me up to speed on the basics of these Williams games.
 
i stock a kit if your going to rebuild yourself for that power supply and it has everything including connectors for the wire harness and i have had a ton of people use my kit and love it and if you have any questions let me know. if you don't want to do the work yourself mecha may rebuild for you.
 
Sent you PM for some spare parts that I need. Please let me know.

A little background info: I'll just preface this post by saying that I've never worked on Williams games before. I don't have a ton of knowledge in this area, but I can follow instructions if you can explain to me what I need to do. I have read through a lot of older posts on Defender repairs and looked through the manual.

I purchased 3 project Defender cabs not too long ago and I'm just getting around to consolidating all the working parts into one cab. I have 3 complete board sets. Only 1 monitor is working.

I've swapped out different boards and trying different combinations of things and so far I'm not having any luck. I'm starting to think that maybe I don't have 1 fully working set of pcbs among the 3 sets I was given. Or maybe the wiring in the cab I'm using is shot.

Issue: When I power the game on I hear the sound that I believe you're supposed to hear. The monitor is turns on and displays a white/gray color and has some rolling (I think it might also turn to a reddish color after a while). The game does not coin up or play blind. The power supply has the +5v +12v and -5v lights lit up. All 4 lights on the ROM pcb stay lit. I can do a test of the sounds and adjust the volume.

Here is where my inexperience comes into play. I'm trying to test voltages, but I can't figure out where/how to do it. I found the location of all the voltages in the manual. If I stick the leads of my multi-meter down into the openings on the connector, it doesn't make contact or get a good enough connection to read anything due to the way the wires are inserted into the connectors. Is there somewhere else I should be testing voltages? If so, could someone please give instructions on where to do it in the most plain way possible?
 
I have 4 ROM boards in total. I tested the voltages on some of the ROM chips and I got anywhere from 8.4v to 9v depending on the ROM board. I have 2 complete main CPU/Vidoe boards. I tested a ROM chip on these and it was moving around between 2v and 3v.

Does this mean the power supply needs to be rebuilt? Are the ROM chips on the ROM board way too high (meaning they might be toast)?

Just in case it's helpful in diagnosing anything, whenever I had the ROM board installed that had the 9v, the game played several more sounds than with the other ROM board (not sure if this is good or bad).
 
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Does this mean the power supply needs to be rebuilt

most if not all power supplies that haven't been already been rebuilt, need to be rebuilt

whenever I get a defender in or any game for that matter, I buy the game figuring the monitor chassis, power supply, game board, etc. will need to be rebuilt, components replaced and factor that into my offer no matter how bad I want the game
so many games on craigslist for top dollar, its absurd how much work is in store and look how much they want for the game

soldered onto a multimeter probe a very thin wire for getting into some of those difficult connectors pins yes can be done
sometimes a knife slice away a small piece of the insulation can reward one with a place to measure but usually the wire goes to a connector where a measurement can be taken

I like installing a potentiometer there in the +5v circuit there on the power
I still cant remember the link for that mod but maybe someone can remind us where that is

also look to that ribbon cable as a source of problems there
so brittle even a slight movement can break the little copper wires in there
when you test the wires for continuity with your multimeter you get a positive test but yet when a "load" is placed on the wire, not enough electrons can pass through the break fast enough to run the game

I would take a rebuilt linear power supply over a brand new switcher any day.
fun to test those capacitors on the power supply with my asr meter and see what the capacitance is. would replace those immediately no matter what my meter said
love taking my dremel tool with the wire brush to all those header pins. maybe even replacing them with the square ones too
a good technician might even remove the connector pins from their housings and hit them with the dremel tool too
make sure all the ground connections are nice and clean on all the grounds there on the metal mounting plate
make sure 3 prong plug has 3 prongs and outlet is properly grounded
now can test if game works

if game still doesn't work right, at least you've crossed off most of the things on the list of things that needs to be done and can focus on more troubleshooting

good luck
 
most if not all power supplies that haven't been already been rebuilt, need to be rebuilt

whenever I get a defender in or any game for that matter, I buy the game figuring the monitor chassis, power supply, game board, etc. will need to be rebuilt, components replaced and factor that into my offer no matter how bad I want the game
so many games on craigslist for top dollar, its absurd how much work is in store and look how much they want for the game

soldered onto a multimeter probe a very thin wire for getting into some of those difficult connectors pins yes can be done
sometimes a knife slice away a small piece of the insulation can reward one with a place to measure but usually the wire goes to a connector where a measurement can be taken

I like installing a potentiometer there in the +5v circuit there on the power
I still cant remember the link for that mod but maybe someone can remind us where that is

also look to that ribbon cable as a source of problems there
so brittle even a slight movement can break the little copper wires in there
when you test the wires for continuity with your multimeter you get a positive test but yet when a "load" is placed on the wire, not enough electrons can pass through the break fast enough to run the game

I would take a rebuilt linear power supply over a brand new switcher any day.
fun to test those capacitors on the power supply with my asr meter and see what the capacitance is. would replace those immediately no matter what my meter said
love taking my dremel tool with the wire brush to all those header pins. maybe even replacing them with the square ones too
a good technician might even remove the connector pins from their housings and hit them with the dremel tool too
make sure all the ground connections are nice and clean on all the grounds there on the metal mounting plate
make sure 3 prong plug has 3 prongs and outlet is properly grounded
now can test if game works

if game still doesn't work right, at least you've crossed off most of the things on the list of things that needs to be done and can focus on more troubleshooting

good luck



i would agree i have rebuilt all mine and i personally like the +5 pot and i have a video on it and sell it as an option to the full rebuild and cap kit. some people don't like pot only because if your not careful you could do damage but if you follow directions it works great and you can put a dab of silicone on it when set so it can't move accidentally.
i have a few customers that had questions on how to modify the pot to fit the pcb so i did a quick video a week or two ago here.
https://www.youtube.com/watch?v=d1ZZ-VOP5GQ&t=4s
 
the 4116 ram uses +5, +12, and -5. if your power supply caps are rotten, you will lose voltage. the MPU caps all the same, you will lose voltage. the crappy Williams headers, you will lose voltage. so you can see, it's like a cascading effect.

the linear power supply board has 2 large plugs. one will take AC voltages in from the transformer, the other will output DC voltages to the boards. the AC plug is prone to burning up, call it a design flaw or whatever. that's why I replace all power supply headers with the black headers, they're more heat resistant. it's also possible for the header for the GIs (coin door lamps) to burn up too, so you have to change all of them out. this is a delicate process. you're never going to use the old headers again, I dial the soldering iron to 700 degrees and pull each pin individually with pliers -- then you suck the old solder out and install the new ones. your replacement headers will be much thicker than the skinny round Williams ones, so make sure the holes are big enough.

splattergatz outlined the ribbon cable situation. you'll find most Williams games failures will stem from the ram (low voltages, usually; bad logic in other instances) and most of the rest will either be bad ribbon cables or PIAs.

if you really want the game to work, you will need to sort out the power supply and replace the ribbon cable at a minimum. if the ram is at fault, you should see like a constant rug pattern. grey screens with lines is more symptomatic of a bad ribbon cable, cause the game can't get the data off the rom board.
 
and you can put a dab of silicone on it when set so it can't move accidentally

great tip
thanks for that. never woulda thought that one up myself


outlined the ribbon cable situation
and replace the ribbon cable at a minimum.
grey screens with lines is more symptomatic of a bad ribbon cable

have to be careful when cutting a ribbon cable without the "regular" ribbon cable cutter. seem to remember a trick you can do but now its escaping me. maybe i used successfully a fresh blade in some type of box cutter against a flat edge like the metal ruler and pushed down hard and held the knife at an angle and pulled extra on the knife to SLICE better or whatever. what you are watching out for is if you dont do it right, the little wires can touch since they are so small because you can damage the cable and not even know it so look out
can barely see them without my magnifying glass

let us know what you find
 
I desolder it out whole. I don't recycle the old one at all. obviously if you don't have the correct tools to do this it will be pretty bad.
 
Finally getting back to this game. I'm going to purchase and install a power supply rebuild kit and I'd also like to re-pin a lot of the connections.

I have a question about replacing the pins as I've never done anything like that before.

I've watched this video from John's Arcade a dozen times:
https://www.youtube.com/watch?v=zxOw6MWjPfk&t=281s

He mentions getting the new pins from Great Plains Electronics. So I just want to confirm if these products are what I should be purchasing to do the job.

Header Pins: Part Number 26-48-1241

Trifurcon Pins: Part Number 08-50-0108 (Should I get 18-20 gage or 22-26 gage, also should I get Tin plated Phosphor Bronze or Tin plated Brass?)

Connectors: Part Number CS156-15-LR (I'm just going to buy the sizes I need instead of cutting them.)
 
Finally getting back to this game. I'm going to purchase and install a power supply rebuild kit and I'd also like to re-pin a lot of the connections.

I have a question about replacing the pins as I've never done anything like that before.

I've watched this video from John's Arcade a dozen times:
https://www.youtube.com/watch?v=zxOw6MWjPfk&t=281s

He mentions getting the new pins from Great Plains Electronics. So I just want to confirm if these products are what I should be purchasing to do the job.

Header Pins: Part Number 26-48-1241

Trifurcon Pins: Part Number 08-50-0108 (Should I get 18-20 gage or 22-26 gage, also should I get Tin plated Phosphor Bronze or Tin plated Brass?)

Connectors: Part Number CS156-15-LR (I'm just going to buy the sizes I need instead of cutting them.)

I always get the ones with the friction lock:
https://www.greatplainselectronics.com/proddetail.asp?prod=26-48-1245

For pins, I'd get 18-20 gauge and you're good on the housings.
 
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Perfect! Thank you! I will purchase the friction kind instead and I'll get the 18-20. Is there a difference in the plating on the Trifurcon pins?

EDIT: Never mind, looks like the 18-20 are only bronze plated. Less decisions makes things easier for me :) Thanks again!


i have EVERYTHING in one rebuild kit and all my kits are 100% molex with trifurcon pins.
https://www.arcadepartsandrepair.co...-d-8359-mega-deluxe-power-supply-rebuild-kit/

and cap kit
https://www.arcadepartsandrepair.co...8359-5773-09474-01-power-supply-105c-cap-kit/

you wouldn't find a more complete and easy to install kit anywhere with the best quality parts.

i have the +5 pot for the mod if you need that too.
 
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