Defender's got me down (again)

YeastLord

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I got this Defender last January and since then it has been working for a total of 2 days. So far I have had all the boards repaired. (ROM issue fixed) That's when the boards worked for 2 days. On day three I fired it up and got what's on the attached pic.
When I power it on I get the initial sound burst. The LEDs all blink once then nothing on the board.
I've seen a few other threads that tell me my voltages seem to be OK. Here they are:

1 -5.096
3 11.94
4 -14.58
5 14.52
6 14.4
12 4.95
13 4.95
14 4.95

Any advice would be greatly appreciated.
Thanks again for the help.
Getting to play it for two days was an evil tease.
 

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I've never seen this exact symptom, but if ever in doubt...

unplug the rom board ribbon. does the picture stay the exact same? if it does it's probably something wrong on the MPU, either that or the ribbon cable is hosed. there's a button between the power and watchdog headers on the MPU, that's the reset button. you can try moving the rom ribbon cable around and hit reset to see if the screen changes or follow the LED codes on the rom board and see if they vary at all.

there's a section on the MPU around the decoder chips where if any of these go bad it will prevent the game from booting. I don't remember the exact parts off hand.

I'm guessing you measured your voltages at the power supply. you need to measure at one of the logic components on the MPU to see if you're losing too much voltage and the chips aren't getting adequate power to operate. I have a picture in my PSU guide for this purpose; I would test at one of the chips near the video header -- DO NOT measure voltage at the 3 ram banks under any circumstance.

the factory headers and plugs are inferior, and the capacitors inline with +5, +12, and -5 are all very old and have probably built up enough resistance to substantially reduce the voltage reaching the logic components. the factory linear power supplies typically operate between 4.95-5.10V depending on the resistor configuration in the +5 circuit -- it's not uncommon to lose almost an entire volt if the aforementioned parts are no good. the lowest I've ever seen any Williams game operate was 4.21V at logic, and it was in a Joust that would otherwise run fine for awhile and then eventually reset during gameplay.

I can supply a list of parts for rebuilding the power supply/MPU/rom board to at least eliminate voltage issues. if you want me to look at your boards we can make arrangements for you to send them to me if you want.
 
More details:
So unknown to me, my son fired up Defender on night 2 and played for several hours without issue. He didn't turn it off. The next morning when my wife went into the garage the screen was "half blue with a bunch of squiggly lines" so she shut it off.

Now if I restart the game 5 time I get 5 different junk images on the screen.
Hopefully tonight I can check voltages.

If I can't come to the source of the problem soon we should talk about sending the boards to you.

-Thanks again for all the help
 
sounds like a dinged up rom cable. especially if it's intermittent.

proper boot LED code is all 4 lights flashing twice. I wish I knew what I know now back when I got my Defender. I wound up junking all the original boards. at least I got a complete other set for $100 back then. they're through the roof now.
 
More details:
So unknown to me, my son fired up Defender on night 2 and played for several hours without issue. He didn't turn it off. The next morning when my wife went into the garage the screen was "half blue with a bunch of squiggly lines" so she shut it off.

Now if I restart the game 5 time I get 5 different junk images on the screen.
Hopefully tonight I can check voltages.

If I can't come to the source of the problem soon we should talk about sending the boards to you.

-Thanks again for all the help

if you need to do a complete rebuild of the power supply i stock the cap kit and the rebuild kit which includes all the headers and connectors and the 18,000uf axial cap.
 
12 4.95
13 4.95
14 4.95


+5 volts isn't high enough for my liking
before you condemn the game boards I would replace those capacitors on the power supply and maybe install that +5 volts potentiometer modification so you can dial in that +5 volts accurately. I don't have that website anymore so I cant pass that along

curious as to what exactly the +5 volts is ON THE game board (on one corner of the 4116) after all the pins insides the connectors/header pins and wires, etc.

those ribbon cables are so delicate/brittle after all these years that you can have a broken copper part of the wire that's touching so it registers as having continuity but under load it cant pass enough electrons to properly operate all inside of the colored insulation there

good luck
 
+5 volts isn't high enough for my liking
before you condemn the game boards I would replace those capacitors on the power supply and maybe install that +5 volts potentiometer modification so you can dial in that +5 volts accurately. I don't have that website anymore so I cant pass that along

curious as to what exactly the +5 volts is ON THE game board (on one corner of the 4116) after all the pins insides the connectors/header pins and wires, etc.

those ribbon cables are so delicate/brittle after all these years that you can have a broken copper part of the wire that's touching so it registers as having continuity but under load it cant pass enough electrons to properly operate all inside of the colored insulation there

good luck

I discourage people from checking at ram. cause we all know what inevitably happens. the voltage will be the same there as any other chip.

I did the 10k potentiometer mod on my Defender. 4.95 at the power supply won't be enough, especially with all the other rotten parts. 4.95 at the chips is more than enough however.
 
I did the power supply cap kit from Bob. Are there other things I need to change on the PS board?

Is this a kit? "maybe install that +5 volts potentiometer "

Thanks for all the help guys.
 
I did the power supply cap kit from Bob. Are there other things I need to change on the PS board?

Is this a kit? "maybe install that +5 volts potentiometer "

Thanks for all the help guys.

Change the .156 headers on the power supply and also each other pcb where the power comes in, as recommended by Mecha. And also, repin the power cables to .156 molex trifurcon pins.
 
I did the power supply cap kit from Bob. Are there other things I need to change on the PS board?

Is this a kit? "maybe install that +5 volts potentiometer "

Thanks for all the help guys.

i have a separate rebuild kit with all the connectors (i only sell trifurcon pins and original molex or amp connectors). if it was mine i completely rebuild them but at a minimum all headers and connectors/pins need to be done.
 
i have a separate rebuild kit with all the connectors (i only sell trifurcon pins and original molex or amp connectors). if it was mine i completely rebuild them but at a minimum all headers and connectors/pins need to be done.

Would that kit be "Williams D-8359 Mega Deluxe Power Supply Rebuild Kit"?
 
Would that kit be "Williams D-8359 Mega Deluxe Power Supply Rebuild Kit"?

defender should have the large heat sink mounted directly on the power supply and yes that D8359 kit is for that model. the D8784 is the one with the heat sink mounted separate and the kits are very similar but not exactly the same.
 
defender should have the large heat sink mounted directly on the power supply and yes that D8359 kit is for that model. the D8784 is the one with the heat sink mounted separate and the kits are very similar but not exactly the same.

what are the differences?

even the caps are identical between them lol
 
what are the differences?

even the caps are identical between them lol

headers, connectors, bridge rectifier, and almost all location numbers all are different. keep in mind that the two have different lead spacing on the 4700uf cap (12.5mm on one and the other has both 12.5mm and 10mm). my kits fit everything perfectly unlike other kits i have seen where you have to strap two radial/snap caps to the board and run wires everywhere which is alot of extra work and personally look like shit in my opinion. the +5 pot mod on mine fits both versions well without all kinds of headache or bending it into a pretzel which i am just finishing testing and will be in the kits soon as standard equipment.
 
headers, connectors, bridge rectifier, and almost all location numbers all are different. keep in mind that the two have different lead spacing on the 4700uf cap (12.5mm on one and the other has both 12.5mm and 10mm). my kits fit everything perfectly unlike other kits i have seen where you have to strap two radial/snap caps to the board and run wires everywhere which is alot of extra work and personally look like shit in my opinion. the +5 pot mod on mine fits both versions well without all kinds of headache or bending it into a pretzel which i am just finishing testing and will be in the kits soon as standard equipment.

what you are talking about, I've never had to do. I generally go up in voltage tolerance on every cap I get, by virtue of this the replacements I install are larger. if this was a tight little power supply it would matter. it doesn't on these. but +1 to you for matching the lead spacings. and of course the placements are different, they're 2 revisions of the power supply. the components are the exact same between them. the only real difference is the later model has overcurrent protection built in (the transistors with the heatsinks) and an external heatsink.

I source the large cap from GPE, I don't do that radial to axial Bob Roberts bullshit hackery.
 
what you are talking about, I've never had to do. I generally go up in voltage tolerance on every cap I get, by virtue of this the replacements I install are larger. if this was a tight little power supply it would matter. it doesn't on these. but +1 to you for matching the lead spacings. and of course the placements are different, they're 2 revisions of the power supply. the components are the exact same between them. the only real difference is the later model has overcurrent protection built in (the transistors with the heatsinks) and an external heatsink.

I source the large cap from GPE, I don't do that radial to axial Bob Roberts bullshit hackery.

https://www.arcadepartsandrepair.com/product-category/components/capacitors/axial-capacitors/

BTW: i am the only vendor with all the large axial capacitors that are all 105C unless your buying from someone i sell them to. (smaller ones can be found in 105c but not the very large ones).
 
defender should have the large heat sink mounted directly on the power supply and yes that D8359 kit is for that model. the D8784 is the one with the heat sink mounted separate and the kits are very similar but not exactly the same.

Ordered the kit.

Thanks for all the help. -Let ya know how it goes.
 
Rebuilt the power supply. Checked all the traces. Checked for cold solder joints. Everything looks good.
Installed it and all three lights came on (+12 +5 and -5)
Checked voltages and they are almost nonexistent. The +12 reads around .09.

Anything obvious jump out at anyone?
Any good place to start looking.

Before all my handy work the voltage were close to tolerance.

-Thanks again for the help
 
Rebuilt the power supply. Checked all the traces. Checked for cold solder joints. Everything looks good.
Installed it and all three lights came on (+12 +5 and -5)
Checked voltages and they are almost nonexistent. The +12 reads around .09.

Anything obvious jump out at anyone?
Any good place to start looking.

Before all my handy work the voltage were close to tolerance.

-Thanks again for the help

for +5, 2N6057 (large heatsink) for +12, 2N3055 (small heatsink). try reseating the transistors. if your +12 doesn't return, I would concentrate on the bridge rectifier, it's not melted is it?
 
The schematics has test points to check the voltages. Start working forwards and you will find the problem. Seems odd that you would lose the -5vdc as well. If you replaced the bridge rectifiers, verify that they are in the correct orientation. Check the fuses and the unregulated voltages as well.

Good Luck!

Kirk S.
 
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