Defender growls no more...

[Arcadenut]

Okay...the growl is back! Still not there yet though. I re-did the ribbon cable between the rom board and cpu. Apparently I didn't clamp it hard enough the first time. I replaced the 2 socketed 7474's and also the one at 7L. I tested the reset pin on the CPU and it's high and when I press the reset it goes low for 1 second (correct?).

So what I see on the display is vertical color bars and it appears to be running the rug test over and over. Also I should note that the 7474's I oredered have the following designation on them...7474AN. Are these compatible? They were stated as 7474n at Jameco's website.

3 of 4 led's light and then go out (1,2,3). I'm telling ya, that 4th led never lights. If I press reset, the 3 led's light and stay on. Question, is it supposed to growl if you press reset?

If you want to test the 4th LED, swap it with #3 and see if you get the same results.

Pin 37 on the CPU should go Low when you press RESET then go back to High after that. When it starts to repeat the rug pattern do you see Pin 37 pulse?

 

[Sirius]

If you want to test the 4th LED, swap it with #3 and see if you get the same results.

Pin 37 on the CPU should go Low when you press RESET then go back to High after that. When it starts to repeat the rug pattern do you see Pin 37 pulse?

Okay...yes, I cant see it do it but when I leave the probe on pin 37 for about 10-15 seconds, it does pulse once. About as long as it takes the rug pattern to loop. I lost the growl but when I turn on the machine I can see it run off some characters, stop and then start the rug pattern. Cant read it, looks Klingon. Before it restarts the rug test it changes to a black background and displays 3 lines of text, and starts over.

As far as the led...I did test the power on all of them. I get about +1.6 on the 3 that light and between -1.18/-1.27 on the 4th that wont light.

Okay...the wife confirmed it for me. Pin 37 pulses when the rug test starts over.

 

[Arcadenut]

As far as the led...I did test the power on all of them. I get about +1.6 on the 3 that light and between -1.18/-1.27 on the 4th that wont light.

3 things to check on the ROM board:

IC21 Pin 12 (13 would be the Input)
Resistor R8
LED #4

Okay...the wife confirmed it for me. Pin 37 pulses when the rug test starts over.

Means the Watchdog is barking causing the game to reboot. You can disable the Watchdog and see if the game gets any further, which might give you a clue as to what the problem is.

To disable the Watchdog you would need to cut the pad between 5M and 5O.

Since your rug pattern has solid bars, it could be a RAM (or addressing) issue.

 

[Sirius]

A Video

Here's a video of my Defender when I turn it on.

 

[Arcadenut]

Here's a video of my Defender when I turn it on.

http://www.youtube.com/watch?v=Qrdfohw5RsY

Looks like your monitor needs a Cap Kit as well.

Did you cut the Watchdog pad or is that with the Watchdog pad still in tact?

Your board looks like it has several issues.

If you have an EPROM programmer, start by verifying that all the ROMS are good and not corrupt.

After that, you'll probably want to fix the RAM issues. Then if you can't get out of book keeping, then you need to look at the CMOS circuit.

 

[Sirius]

That's with the watch dog intact, and all the RAM is new. No EPROM programmer (yet). I'll try cutting the watchdog later.

Can you recommend a reasonable programmer? I've read too much about how this model will read this chip but not this chip, blah, blah, blah, etc, etc...

Thanks...

 

[Arcadenut]

That's with the watch dog intact, and all the RAM is new. No EPROM programmer (yet). I'll try cutting the watchdog later.

Can you recommend a reasonable programmer? I've read too much about how this model will read this chip but not this chip, blah, blah, blah, etc, etc...

Thanks...

There are quite a few good threads on here about which ones to get. It all really depends on what you want to spend and how often you plan on using it.

I've had mine for many years, and I think it was $450 or something like that. Does most older chips out of the box, but requires adapters for some stuff (such as the 2532 which Williams uses). Adapters can be pricey.

The TopMax is a good one but it's almost twice what I paid for mine. However, it is USB, where as mine is Parallel.

 

[Sirius]

I got Growl!

What a beautiful weekend in Michigan...the sun was shinning, the weather was warm and my Defender is fixed! (mostly). Had several issues...lost the growl due to a bad connection on the speaker wire harness (fixed). Replaced the rom board with one from AMC...thanks Andre, board works great. Replaced both video decoders with fresh burns from Hobby Roms, thanks Steph, love the labels. Upgraded the ram to 4164 thanks to Pacmandotcom. Recapped both the monitor and the power supply and replaced the caps on the main board. Only problem I had with the monitor was the "dreaded" curl. After recapping, it was still there. After reading a few posts on the subject and all the remedies put forth, things did not look good until I found the link to Bob Roberts site that explained how to adjust the can on the interface card. Worked perfectly, and now no curl.

The only real issue I have is with is the monitor test pattern. As you can see from the picture I've posted, colors 4 & 5 (white & black) are reversed? The manual states that it should be white, then black. This indicate a fault in 2E, 1C, or 2C chips. Is this really something to fuss with, or does anyone know exactly which of the 3 chips may be at fault? I've also included a new video. Take a look and if anyone see's anything that doesn't look right, let me know. Thanks to everyone for their help and suggestions...

http://www.youtube.com/watch?v=sS03-xWWDPQ

...and now back to Road Blasters

 

[Sirius]

Does anyone know the cause for the horizontal lines that appear in the test pattern?

 

[Arcadenut]

Does anyone know the cause for the horizontal lines that appear in the test pattern?

You need to adjust your monitor. In the first pic, you should be able to see the outter box.

The second one could be because you need to adjust the picture, or it could be your monitor needs a cap kit.

 

[YellowDog]

The horizontal lines are the refresh lines. You need to turn the brightness down. You may need to turn the contrast up to compensate.

ken

 

[Sirius]

The monitor was capped. I'll try turning down the brightness and adjusting the contrast.

What about the black and white being reversed in the test pattern? Also does Defender store fictitious scores and names for high score by default?

 

[YellowDog]

I'm not sure about the black and white being reversed. That seems strange. I'll try to remember to look at it the next time I have one on my bench.

Defender, as all later Williams games do, has a default high score table in ROM. The initials that are in the games are all initials of developers, testers and other people that worked at Williams at the time.

ken

 

[Sirius]

I'm not sure about the black and white being reversed. That seems strange. I'll try to remember to look at it the next time I have one on my bench.

Defender, as all later Williams games do, has a default high score table in ROM. The initials that are in the games are all initials of developers, testers and other people that worked at Williams at the time.

ken

I expected the high scores to clear completely, but they didn't. Kinda thought they were default. Stands to reason that they wouldn't want them to be blank in attract mode.

As far as the test pattern, the book says "double width band, half width bands, transposition or missing bands indicates a fault in 2E, 1C, or 2C chips". I have the chips so I may try and determine which is at fault and replace it.