Dead Defender

[jehuie]

I got this dead defender and the main fuse was blown so I replaced it, disconnected the main board and fired it up. I had voltages that seemed to be not to crazy (except for the last one listed below) so I powered it down and plugged in the pcb cable and fired it back up. Now the monitor glows nicely and the lights all come on, but there's no sound and no video at all.

The led's on the rom board are all lit....they don't flash at all. Pressing reset on the cpu doesn't do anything. They all stay lit. Pressing the various buttons (advance, etc.) don't have any effect either. It just sits there. I looked up the codes but I can't tell what it means when all the lights are lit. It's not listed as one of the option on the list I have. Any ideas?

Also, here's the voltages....should I get these closer (rebuild the PS) before proceeding?

4J2-12 = (should be +5) reads just over +5
4J2-3 = (should be +12) reads +12
4J2-5 = (should be +12 unregulated) reads +14
4j2-1 = (should be -5) reads -5.2
4J2-4 = (should be -12 unregulated) reads -14.5
4J3-3 = (should be +27) reads 12.1

 

[Dokert]

The last voltage indicates that BR2 is bad, the rest are fine. Rebuild the power supply before you continue onward.

 

[jehuie]

The last voltage indicates that BR2 is bad, the rest are fine. Rebuild the power supply before you continue onward.

Thanks. I was thinking there might be a sign of life without it but I'll do that. I had already looked up the rebuild kit from BR so I'll order that. Anything else I should order for the game while I'm at it? I was already planning to get the battery upgrade kit. Any other recommendations?

Oh, and I also ordered some spare cap kits including the one for this monitor.

 

[Dokert]

also need the 18K 25v cap for the power supply, and the BR2 does not come in the kit either.

 

[jehuie]

So I ordered the PS rebuild kit from Bob along with the 18k cap and some other goodies but the cap is the wrong size. It's ratings are correct but it has radial leads instead of axial leads

The yellow cap in the pick is the old one. The one in my hand is the new one. Is there a good way to make this work without it seeming really hinky?

 

[p1899m]

solder wires from the spots on the pcb to the legs on the new cap. Zip tie the cap to the board. Should work fine and not look too bad.

 

[Dokert]

So I ordered the PS rebuild kit from Bob along with the 18k cap and some other goodies but the cap is the wrong size. It's ratings are correct but it has radial leads instead of axial leads

The yellow cap in the pick is the old one. The one in my hand is the new one. Is there a good way to make this work without it seeming really hinky?

Bob does not sell the correct axial cap, but the radial that he has provided will work just fine. The only place that sells the correct axial cap is Ed at greatplainselectronics.com . You will need to solder wires to that cap and you will be good to go. Make sure that you zip tie the cap to the board too.

 

[jehuie]

Ok I have finally completed the PS rebuild including the big cap and the bridge rectifier (BR2). Now I'm getting the following voltages but the game is behaving the same as before.

4J2-12 = (should be +5) reads 4.94
4J2-3 = (should be +12) reads 11.87
4J2-5 = (should be +12 unregulated) reads 14.26
4j2-1 = (should be -5) reads -5.2
4J2-4 = (should be -12 unregulated) reads -14.55
4J3-3 = (should be +27) reads 32.3

There are no sounds and no video (not sure the monitor is working but it does glow), coining up doesn't make any sound either. All LED's are lit on the power supply and all 4 LED's are lit on the rom board. Pressing the various buttons in the coin-door has no effect at all.

What does it mean if all 4 LED's are lit? It's not in the manual as far as I can tell.

 

[Arcadenut]

Ok I have finally completed the PS rebuild including the big cap and the bridge rectifier (BR2). Now I'm getting the following voltages but the game is behaving the same as before.

4J2-12 = (should be +5) reads 4.94
4J2-3 = (should be +12) reads 11.87
4J2-5 = (should be +12 unregulated) reads 14.26
4j2-1 = (should be -5) reads -5.2
4J2-4 = (should be -12 unregulated) reads -14.55
4J3-3 = (should be +27) reads 32.3

There are no sounds and no video (not sure the monitor is working but it does glow), coining up doesn't make any sound either. All LED's are lit on the power supply and all 4 LED's are lit on the rom board. Pressing the various buttons in the coin-door has no effect at all.

What does it mean if all 4 LED's are lit? It's not in the manual as far as I can tell.

The LED indicates errors (or lack of errors). Starting on Page 3 of this PDF will explain them:

http://arcarc.xmission.com/PDF_Arca...etup_Booklet_(16P-3001-103_R-T)_July_1981.pdf

Where are you measuring the voltages at? If you're testing at the connector, then try testing them at the RAM and see what they are.

To test the sound board, there is a button on it that you can press and it should start looping with sound effects.

Do you have another monitor you can test with?

Check the Ribbon Cable on the ROM board. Try moving it or flexing it to see if you get any change.

 

[jehuie]

The LED indicates errors (or lack of errors). Starting on Page 3 of this PDF will explain them:

http://arcarc.xmission.com/PDF_Arca...etup_Booklet_(16P-3001-103_R-T)_July_1981.pdf

Where are you measuring the voltages at? If you're testing at the connector, then try testing them at the RAM and see what they are.

To test the sound board, there is a button on it that you can press and it should start looping with sound effects.

Do you have another monitor you can test with?

Check the Ribbon Cable on the ROM board. Try moving it or flexing it to see if you get any change.

I've read that part of the manual but it doesn't show what it means if all 4 lights are on and stay on (no blinking at all). I'm measuring at the connector on the power supply. I'd like the +5 to be a little higher but I don't see an adjustment for that on the PS. Am I just missing it?

And I don't have another 4600 monitor to test it with. I have a G07 that's working great in my Phoenix. It seems like it had a different type of connector for the game input though. I suppose I could adapt something.

Interesting about the sound button. I didn't know about that...when I pressed it, it started making it's sounds....scared me. It was turned up really loud!

 

[Arcadenut]

I've read that part of the manual but it doesn't show what it means if all 4 lights are on and stay on (no blinking at all). I'm measuring at the connector on the power supply. I'd like the +5 to be a little higher but I don't see an adjustment for that on the PS. Am I just missing it?

And I don't have another 4600 monitor to test it with. I have a G07 that's working great in my Phoenix. It seems like it had a different type of connector for the game input though. I suppose I could adapt something.

Interesting about the sound button. I didn't know about that...when I pressed it, it started making it's sounds....scared me. It was turned up really loud!

GO7 should work just fine. You could probably just put the games back to back and run the wires (if they are long enough) from one cab to the other so you don't have to pull the monitor. If they are not long enough, pull the G07 and set it outside the Defender.

If you get the same results you can try the 4600 in your Phoenix to verify that it's good. If both monitors are good, then your problem is either on the CPU board or the ROM board.

As long as your +5 isn't lower then say 4.7 the board should boot.

If you know someone else locally that has a Defender you could borrow their boards (or take your boards over to them) and test them by swapping them out one at a time.

 

[YellowDog]

I've read that part of the manual but it doesn't show what it means if all 4 lights are on and stay on (no blinking at all). I'm measuring at the connector on the power supply. I'd like the +5 to be a little higher but I don't see an adjustment for that on the PS. Am I just missing it?

When the boards are powered up the base state for the LEDs is to be on. The CPU turns them off and then turns them on again. If you are not seeing them blink, the CPU is not running.

Check pin 36 on the CPU with a logic probe. It should be HIGH and go LOW for 1 second when the reset switch is pressed. If it is pulsing, then the watchdog circuit is messed up.

If it is HIGH, but you are still not seeing the LEDs. Try recrimping the ROM cable. Arcade Solution has a great reference on this: http://arcadesolution.com/ribbon.html. Just ignore the first part about cutting cables and go to the part with the vise.

Interesting about the sound button. I didn't know about that...when I pressed it, it started making it's sounds....scared me. It was turned up really loud!

The sound card is a separate computin device that communicates with the MPU board via the cable from the ROM. When you press the reset button on the sound card it forces the sound card into a loop playing the first sound. You have to power down to reset the card.

ken

 

[Arcadenut]

Check pin 36 on the CPU with a logic probe. It should be HIGH and go LOW for 1 second when the reset switch is pressed. If it is pulsing, then the watchdog circuit is messed up.

Do you mean Pin 37?

 

[YellowDog]

Do you mean Pin 37?

Yep, sorry. That's what happens when you do the math in your head .

It is the RESET pin (the 4th pin from the top on the right hand side).

ken

 

[jehuie]

Well the RESET pin seems to behave properly according to how you described it. No pulsing and when I press reset it acts as it should.

I went through and re-seated all socketed chips on the main board and the rom board and cleaned the gunk off of the dirty ones with Tarn-X. Still acts the same. I re-crimped the existing cable between the two boards but I don't have a fresh one to crimp on there yet so I don't have a good way to swap that yet. I do have a friend who has a working Defender but I'm not sure if he has ready access to it now or not so I've got a call into him and I'm waiting to hear back.

One question...the interlock switch inside the coin-door has one wire that's disconnected. Would that have any effect on my testing? For instance, would it keep the LED's from flashing on start-up or keep it from running any of the tests when I press the reset button?

I'll go solder the wire back on in a bit...but I'm just curious how it could have been affecting things all along.

 

[Arcadenut]

One question...the interlock switch inside the coin-door has one wire that's disconnected. Would that have any effect on my testing? For instance, would it keep the LED's from flashing on start-up or keep it from running any of the tests when I press the reset button?

I'll go solder the wire back on in a bit...but I'm just curious how it could have been affecting things all along.

That is the Memory Protect. It is supposed to prevent the CMOS from getting corrupt when the coin door is open.

It should not affect the startup of the game.

You could check pins 8 - 20 on the CPU with your Logic Probe and see if there is any activity there. You could also check pins 34 and 35 to see if they are pulsing.

If 34 and 35 are pulsing but you're not seeing any activity on 8 - 20, then you might have a bad CPU.

 

[jehuie]

You could check pins 8 - 20 on the CPU with your Logic Probe and see if there is any activity there. You could also check pins 34 and 34 to see if they are pulsing.

If 34 and 35 are pulsing but you're not seeing any activity on 8 - 20, then you might have a bad CPU.

Thanks, I just did. What does it mean if NONE of the pins on the CPU are pulsing?

 

[Arcadenut]

Thanks, I just did. What does it mean if NONE of the pins on the CPU are pulsing?

Download this:

http://arcarc.xmission.com/PDF_Arca...Theory_Later_PCBS_(16P-3001_301)_Oct_1981.pdf

Go to page 12 (13 of the pdf) and look at the Clock Generator section.

If you don't understand what the text is saying, don't worry a lot of it is over my head too . The Diagram on page 13 shows the clock section of the board.

Start with the Crystal and make sure it's good (Logic probe should show it pulsing). If it's not pulsing, replace it and see what happens.

If it's pulsing then check pin 8 of 7P.
If that's pulsing, check pin 8 of 6R.
If that's pulsing, then go to page 14 and test Pin 5 of 6D
Then Pin 9 of 5D.

7474's seem to go bad a lot on the Defenders. In some cases you can use a 74LS74, but not in all. I found that some of the 7474's can only be replaced by a 7474 due to the speed of them. For testing you can use a 74LS74. When I replaced a few 7474's with 74LS74 I saw artifacting in the video (looked like sparkling).

 

[jehuie]

Holy cow, thank you Arcadenut! I haven't tried any of that yet but you put some definite work into looking that up and taking the time to type it all up for me. I really appreciate that!

 

[jehuie]

Start with the Crystal and make sure it's good (Logic probe should show it pulsing). If it's not pulsing, replace it and see what happens.

If it's pulsing then check pin 8 of 7P.
If that's pulsing, check pin 8 of 6R.
If that's pulsing, then go to page 14 and test Pin 5 of 6D
Then Pin 9 of 5D.

Ok I followed some of this but then got stuck. First, the crystal is pulsing which is too bad because that would be an easy fix! Pin 8 of 7P is pulsing. So is pin 8 of 6R. So I'm with you so far.

Question #1: If I'm understanding this right, shouldn't pin 6 and 9 of 6R be pulsing also? If so, then I've got a problem there because pin 6 is not. So does that mean I should try replacing that chip (assuming I can find one)?

Question #2: I see where you got the info about checking 6D and 5D. However, when I look at the board layout, there's no chip in either of those spots. There's a 5C and a 5E. But there's nothing near where 6D would be at all. What am I missing?

Thanks again!