Defender Toasted MPU

Zinfer

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Wow - just wow. Never seen an IC cooked this badly. And it's hard for me to believe that just +5v can do all this damage. I found this complete Defender on Craigslist and started into it last night.
Is it common to mix ram? some of them are 9016's and others are 416P's. I'll probably end up replacing all rams. What ram are used these days in a Defender?
This socket in particular just crumbled as I was removing it. I'm thinking this board will be ok but it got really hot under the socket.
Not sure what would have caused this, as I replace the sockets and ram I sure wouldn't want to have all my work fry again.
PCB work and updates are at www.zinfer.com/defender.htm
 

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Defender power supplies have been known to fail hot, i.e. the whole 27V goes flying up the +5V unimpeded. Taking a quick look at the pictures, you may wish to save yourself much heartache (and probably a few $$) and buy a new MPU board.

Also, meter the power supply outputs. The LEDs will light once a minimum voltage is sensed. There is no overvoltage circuit on the Defender PS, so it might run hot.

ken
 
Yea, did that. Both led's lit on power supply, all 4 lit on Rom board. I have just enouph 16pin sockets inhouse to replace the bad off/burnt/melted. Bookoo bunch of 4116's. But I haven't metered the outputs of the ps yet. And I also need to meter those traces on the board under the socket to see if there's any broken. May actually be able to hook it back up tonight if I get ambitious.
But I'm concerned about the mixing of the ram. So I may pull all of it out and replace all of them, I think 24, don't know if I have that much.
If I find 24v to the board then I'm going to just stop and look more at the ps.
 
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You can mix and match RAM if you want. Those different part numbers are all equivalent. It doesn't matter if you mix them or how. You can also very easily modify 4164's to work as 4116's by bending up a few legs and soldering jumpers to them. But most people wind up replacing all the 4116's with 4164's and modifying the power connector (or the board) to support them. I *have* seen 4116's fail shorted before, but never anything that severe.

Those original Defender power supplies are pretty crummy. Definitely test the outputs, see what happened there. It's possible that the fuses got bypassed too - allowing stuff to cook. I know that some people love those old Williams supplies, but a modern switcher is so much less likely to blow stuff up...

-Ian
 
Yea, did that. Both led's lit on power supply, all 4 lit on interface board. I have just enouph 16pin sockets inhouse to replace the bad off/burnt/melted. Bookoo bunch of 4116's. But I haven't metered the outputs of the ps yet. And I also need to meter those traces on the board under the socket to see if there's any broken. May actually be able to hook it back up tonight if I get ambitious.
But I'm concerned about the mixing of the ram. So I may pull all of it out and replace all of them, I think 24, don't know if I have that much.
If I find 24v to the board then I'm going to just stop and look more at the ps.

The power supply board needs to be rebuilt. There are 3 LED's on it. +5V, +12V and -5V.

You can mix and match RAMs as long as they are the same type. 4116s go with 4116s and 4164s go with 4164's and never the twain shall mix, unless you like nice sizzling sounds and the smell of frying silicon.

Switchers are not the panacea for all ills. Try your search-fu out and look up some of the threads regarding CMOS issues and switchers on Williams boards.

If you decide to rebuild the power supply, there are several of us that do that work as well as selling rebuilt power supplies. Additionally, you can use the later power supply boards (the kind used in Joust, Robotron, etc.) with some small changes.

ken
 
Additionally, you can use the later power supply boards (the kind used in Joust, Robotron, etc.) with some small changes.

That's my latest Defender upgrade. Robotron PS with on-board over voltage protection installed and running great. :)
 
Hmm, well I looked at it again tonight and spent a little more time than I had previously with a meter. Yea the power supply board had an 8amp ceramic fuse dead center that was blown. I couldn't find any figures in the manual on fuse amp replacement so I stepped down to a 5amp. I now have a +12v power light on the power board. The main board has long been removed and on the bench. Just checking voltages. Sure enouph I'm getting 30v at Pin 5 of the pcb power connector.
I'm also getting -5v on the coin lamp ground and -5v on the coin lamp 6.5v line. So that's goofy voltage. I seem to have lost an led on the Rom board down from 4 to 3. I did a heat check on the Rom board and ouch! shut power off. That's it, this thing has more problems than I thought.
I pulled all the boards including power out of the cabinet and packed them up into a box ready to ship. Andre Chromy did such a fantastic bang up job for me on Stargate I was going to just send everything off to him to give it the once over and bulletproof it.
But if OEM is going to fail and cook all the boards again I'd seriously like to look into what's involved in trying to stop this from ever happening again. The damage looks like it could seriously start a fire and these electronics are not getting any easier to find.
I've emailed him a couple times with no reply. Or maybe I'm just impatient. But man am I ever looking forward to playing Defender again. But this type of thing can't happen again.
This job is beyond just changing a few rams and sockets out. This is going to be a job for someone with a rig and who's been repairing Defenders for a few years. Basically someone who knows what they're doing with Williams - and that rules me out.
 
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Looking more indepth into the Power supply rebuild kit (Deluxe)http://therealbobroberts.net/wmsdlx.html I mean, I could install that myself. I'd be spending nearly $50.00 on the Power supply kit shotgunning.
Hard to look in a crystal ball to see what I'm going to bump into after that. What do you guys think? I know it's easy to just start traveling down the road and getting over your head and it seems to really prolong the pain on a project that much longer. I just think it's a safer bet to send it off to a defender pro rather than hit a snag and get stuck later on. I could definitely run this PS repair, it's just what am I going to hit after that?
Hard to say. It is tempting to run that ps kit now. Well, order it and get it in next week anyhow.
 
Honestly, I wouldn't waste the time rebuilding that Defender PS. If you really want to stay "stock", then send it off to YellowDog as a donation and buy one of his later rev power boards. Those supplies were crummy when they were new.

Or, just use a switcher. Some complain of periodic lost high scores - but I haven't had problems with my Robotron. Additionally, which would you rather lose, your high scores, or every board in the machine?

-Ian
 
Some complain of periodic lost high scores - but I haven't had problems with my Robotron.
You wouldn't have problems in a Robotron, the switcher memory issues are Defender-specific. Defender uses a 5101 cmos, Stargate and up use 5114 or 5514. The 5101 can be corrupted on shutdown when running a switcher, I've seen it happen on a lot of boards. Zinfer, after looking at your cpu board, I'd find a new one. Between the corrosion, fire and way-too-high voltages, I wouldn't trust it even if it managed to come back to life. If your rom board saw bad voltage it may have problems too. Yellowdog probably has boards for sale, and if for some reason he's out of Defender gear I have some working spares kicking around. As for the PS, my first choice is a retrofitted Joust/Robotron, 2nd a switcher, 3rd the original Defender linear.
 
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Looking more indepth into the Power supply rebuild kit (Deluxe)http://therealbobroberts.net/wmsdlx.html I mean, I could install that myself. I'd be spending nearly $50.00 on the Power supply kit shotgunning.
Hard to look in a crystal ball to see what I'm going to bump into after that. What do you guys think? I know it's easy to just start traveling down the road and getting over your head and it seems to really prolong the pain on a project that much longer. I just think it's a safer bet to send it off to a defender pro rather than hit a snag and get stuck later on. I could definitely run this PS repair, it's just what am I going to hit after that?
Hard to say. It is tempting to run that ps kit now. Well, order it and get it in next week anyhow.

While rebuilding it - based on age, I'd recap the whole thing.
Ya know - you can still buy axial electrolytic caps for these rather than rigging in radial caps.
 
You wouldn't have problems in a Robotron, the switcher memory issues are Defender-specific. Defender uses a 5101 cmos, Stargate and up use 5114 or 5514. The 5101 can be corrupted on shutdown when running a switcher, I've seen it happen on a lot of boards. Zinfer, after looking at your cpu board, I'd find a new one. Between the corrosion, fire and way-too-high voltages, I wouldn't trust it even if it managed to come back to life. If your rom board saw bad voltage it may have problems too. Yellowdog probably has boards for sale, and if for some reason he's out of Defender gear I have some working spares kicking around. As for the PS, my first choice is a retrofitted Joust/Robotron, 2nd a switcher, 3rd the original Defender linear.

The type of CMOS memory is immaterial. Even non-volatile memory.

The CMOS issues are architecture related, not specific to Defender. The basic architecture of the video games derives from the pinball architecture. All Williams designed games from Defender through Inferno have this issue.

The real issue is the architecture of the 6800 family (which includes the 6809). On shutdown, as the power drains from the system and the voltage drops, at some point the voltage hits a threshold and the CPU starts to randomly write into the memory space. If it writes into RAM, no big deal, it will get reinitialized the next power up anyway. If it writes to ROM, again, no big deal, the ROM is read only. But if it writes into the CMOS, bye-bye high scores or settings. To get around this, the engineers at Williams designed the +5V (the only voltage the CPU uses) with a large reservoir (that big capacitor on the power supply) and a circuit that uses the unregulated 12V line to sense when the power is off. When the 12V unreg line voltage drops a CMOS write protect circuit kicks in and prevents the CPU from writing into the CMOS. During that time, the CPU continues to function until it drains the big cap and then blasts memory. But the CMOS is protected.

Switchers do not have that reservoir. When a switcher is turned off, the 12V drops at the same rate or slower (there is less drain on the 12V) than the +5V. So the memory protect does not always have time to kick in before the CPU barfs bits all over the address space. It is just a matter of time before it whacks your CMOS, regardless of the game.

For the non-Williams designed games (Moon Patrol, MakeTrax, Aeroboto, 1942), they have a different architecture and so do not share these issues.

Despite some people's mistaken assertions, I have nothing against switchers. I run them all the time in my JAMMA games. But for the Williams "Classics", I always rebuild and use an original power supply.

ken
 
He apparently doesn't have any and I think you'd have to hack the original harness to incorporate it.
 
This? http://www.arcadeshop.com/pics/wms-ps.jpg
At least this way I wouldn't have to hack a harness up. Thing is it appears to be missing the -12. But then I'd have to go check shematics. I'm pretty sure but not positive that there was a -12 that went to the original harness. That would probably be the most painless, but a standard switcher would then mean I'd have to build a harness as well.

I'll start with the power supply and find out where I am on boards. Just not sure I want to put any money into something that's going to blow up like this again someday so the linear is not looking as a viable or reliable option. Andre seems to think that if 30v hit the MPU it probably toasted every chip on it. But with any luck it just hit the Ram(?) Can you imagine a classic board having to be pitched? argh!

You wouldn't have problems in a Robotron, the switcher memory issues are Defender-specific. Defender uses a 5101 cmos, Stargate and up use 5114 or 5514. The 5101 can be corrupted on shutdown when running a switcher, I've seen it happen on a lot of boards. Zinfer, after looking at your cpu board, I'd find a new one. Between the corrosion, fire and way-too-high voltages, I wouldn't trust it even if it managed to come back to life. If your rom board saw bad voltage it may have problems too. Yellowdog probably has boards for sale, and if for some reason he's out of Defender gear I have some working spares kicking around. As for the PS, my first choice is a retrofitted Joust/Robotron, 2nd a switcher, 3rd the original Defender linear.
 
And you've never had this happen to your Defender?
Apparently even Williams saw this problem so they veered away from this power supply with their very next title release.
I don't see the sense in rebuilding this power supply when williams themselves ditched it.

The type of CMOS memory is immaterial. Even non-volatile memory.

The CMOS issues are architecture related, not specific to Defender. The basic architecture of the video games derives from the pinball architecture. All Williams designed games from Defender through Inferno have this issue.

The real issue is the architecture of the 6800 family (which includes the 6809). On shutdown, as the power drains from the system and the voltage drops, at some point the voltage hits a threshold and the CPU starts to randomly write into the memory space. If it writes into RAM, no big deal, it will get reinitialized the next power up anyway. If it writes to ROM, again, no big deal, the ROM is read only. But if it writes into the CMOS, bye-bye high scores or settings. To get around this, the engineers at Williams designed the +5V (the only voltage the CPU uses) with a large reservoir (that big capacitor on the power supply) and a circuit that uses the unregulated 12V line to sense when the power is off. When the 12V unreg line voltage drops a CMOS write protect circuit kicks in and prevents the CPU from writing into the CMOS. During that time, the CPU continues to function until it drains the big cap and then blasts memory. But the CMOS is protected.

Switchers do not have that reservoir. When a switcher is turned off, the 12V drops at the same rate or slower (there is less drain on the 12V) than the +5V. So the memory protect does not always have time to kick in before the CPU barfs bits all over the address space. It is just a matter of time before it whacks your CMOS, regardless of the game.

For the non-Williams designed games (Moon Patrol, MakeTrax, Aeroboto, 1942), they have a different architecture and so do not share these issues.

Despite some people's mistaken assertions, I have nothing against switchers. I run them all the time in my JAMMA games. But for the Williams "Classics", I always rebuild and use an original power supply.

ken
 
I thought the 5114 disabled writes at a voltage above where the 6809 goes screwy, it sucks that they're all susceptible. How often does it hit non-Defenders? I've never run into a switcher issue on Stargate and up machines.


The type of CMOS memory is immaterial. Even non-volatile memory.

The CMOS issues are architecture related, not specific to Defender. The basic architecture of the video games derives from the pinball architecture. All Williams designed games from Defender through Inferno have this issue.

The real issue is the architecture of the 6800 family (which includes the 6809). On shutdown, as the power drains from the system and the voltage drops, at some point the voltage hits a threshold and the CPU starts to randomly write into the memory space. If it writes into RAM, no big deal, it will get reinitialized the next power up anyway. If it writes to ROM, again, no big deal, the ROM is read only. But if it writes into the CMOS, bye-bye high scores or settings. To get around this, the engineers at Williams designed the +5V (the only voltage the CPU uses) with a large reservoir (that big capacitor on the power supply) and a circuit that uses the unregulated 12V line to sense when the power is off. When the 12V unreg line voltage drops a CMOS write protect circuit kicks in and prevents the CPU from writing into the CMOS. During that time, the CPU continues to function until it drains the big cap and then blasts memory. But the CMOS is protected.

Switchers do not have that reservoir. When a switcher is turned off, the 12V drops at the same rate or slower (there is less drain on the 12V) than the +5V. So the memory protect does not always have time to kick in before the CPU barfs bits all over the address space. It is just a matter of time before it whacks your CMOS, regardless of the game.

For the non-Williams designed games (Moon Patrol, MakeTrax, Aeroboto, 1942), they have a different architecture and so do not share these issues.

Despite some people's mistaken assertions, I have nothing against switchers. I run them all the time in my JAMMA games. But for the Williams "Classics", I always rebuild and use an original power supply.

ken
 
I can't tell from the image, but it looks like it's the same configuration (voltagewise) as the Arcadeshop version only with no harness needed on the as version. It's also $10 more. I'm wondering if the amperage or robustness of the unit is superior to the as version. Thanks for that tidbit at the bottom though. That clears up alot with the sound board voltage. The only thing I can see as a difference is with the plugging and pulling, you could theoretically crack that pcb mounted off the side of the as version.

I had the Bob Roberts version in my Defender before switching to the Robotron supply. It's the second pic from the bottom of this page:
http://www.therealbobroberts.net/parts.html
IIRC, the -12 is only used for the sound board, which uses an on board voltage regulator to make 5v from the +12 and -12. The sound board works fine with -5 in place of -12.
 
Yea, like you, I'd much rather run the Robotron version but didn't see anything on epay.
Although, I'm not sure with that, how badly I'd have to hack up an original harness? I really don't want to do that. I'd like to keep it as original as possible, yet as 'safe' as possible.
Talked with Yellowdog and he doesn't have any prebuilt and ready to go. I own a Stargate and I haven't had one problem with that ps since day one. Just beyond belief this ps could do that to itself the way it did. I'm still stunned. However, that being said, just seeing the blown 8amp ceramic fuse in F3 was enouph to tell me that this game HAD been trying to tell somebody something before it commited hara kiri.
F3 is supposed to be running a 4amp slow blow. Not an 8amp ceramic for god's sake. that's like begging for this to do itself in. Which makes me wonder if this example narrows down why all these Defenders are jumping off cliffs. Just increase the fuse amperage! Yea that's the ticket!
The guy I bought this from, which hated video games and a big old-school pinball fan, said it looked like the weak onboard batteries stressed the ram. :p
Looking at it now, I suppose at least I got a monitor and marquee for $150 bucks. The coindoor's not an original Defender brushed metal, although I wish.
I may just go ahead and order BR's version, as I'm going to pick up the Lithium battery kit and try my best with the board I've got unless someone has a working MPU for sale. I can't see any harm in trying to run this board. But I'll keep my eyes open, I have no idea how this will act when it has the proper voltage it needs. Although I can guess it may have a dead short in it. One of my LED's went off on the rom board so I may just load those eproms up and see if the checksums check out.
Ok, screw it, I'm ordering the BR ps. It's all hypothetical drivel now. :)

I can't tell from the image, but it looks like it's the same configuration (voltagewise) as the Arcadeshop version only with no harness needed on the as version. It's also $10 more. I'm wondering if the amperage or robustness of the unit is superior to the as version. Thanks for that tidbit at the bottom though. That clears up alot with the sound board voltage. The only thing I can see as a difference is with the plugging and pulling, you could theoretically crack that pcb mounted off the side of the as version.
 
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