Defender Troubleshooting

pinballdirec

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I have a Williams Defender that is reporting a Ram / Rom error on the CRT. The 4 L.e.d's blink once and then go blank. Anyone have any idea what error this is? Kevin
 
Wow. It sounds like all my "broken record" nagging about RAM voltages and crimping cables is starting to pay off. ;)

The voltages you are looking on the RAMS are:

picture.php


ken
 
Thanks Everyone... I'm getting 5.15 on all the boards connections except the CPU, I'm getting about 4.85 v - 4.93 v. If I unplug the CPU I get 5.15 at the connection.

On the 4116 chips I'm getting about 4.80v.

I crimped the ribbon cable on the unattached side, I was sure how to crimp the attached side.

I'm still on getting the 4 LED's to flash once. I do get sound.

I have a switching power supply installed also.

any ideas where to look next? Kevin
 
Last edited:
Thanks Everyone... I'm getting 5.15 on all the boards connections except the CPU, I'm getting about 4.85 v - 4.93 v. If I unplug the CPU I get 5.15 at the connection.

On the 4116 chips I'm getting about 4.80v.

I crimped the ribbon cable on the unattached side, I was sure how to crimp the attached side.

I'm still on getting the 4 LED's to flash once. I do get sound.

I have a switching power supply installed also.

any ideas where to look next? Kevin

BEFORE you start looking elsewhere, you need to get the 4.80 to at least 4.95. So you still have some kind of power problem on cpu board. Look at caps and feel for hot chips. Something is pulling the 5 volts down.
 
I cleaned the power connection pins on the CPU and now I have 5.15v on the 4116 chips, but still have only getting the 4 leds to flash once.
 
I cleaned the power connection pins on the CPU and now I have 5.15v on the 4116 chips, but still have only getting the 4 leds to flash once.

All 4 LEDs flash once then go out? Do they all stay out?

You said you hear sound, is it the "Defender growl" or something else?
 
www.arcadesolution.com has a set of self help pages. One of which shows how to use a vise to crimp the ribbon cable connectors. Just skip over the first part about how to replace the ribbon cable and follow the directions on crimping the connectors. Remember:
(1) they are plastic so gently means gently.
(2) don't forget to put a piece of soft wood under the board side. If you don't you can break the pins, crack the solder or just plain break the board.

ken
 
I found this post with the same problem as mine...


Yesterday my Defender started acting up with the exact same symptoms
as yours. Start up sounds and then the never ending rug pattern that
didn't look quite normal. None of the 4 LED's would light up after
the initial power on blink. One time it did make it out of the rug
pattern and the text said multiple ram errors plus tons of other
errors I can't remember. This at least clued me in that it was some
major pathway screwing up and not a single IC.

The problem did turn out to be the ribbon cables. If I remove and
clean the pins with sand cloth and then spray with contact cleaner the
game works great.
 
Be very careful what you clean the pins with as this may clean up issues now and give more headaches later. The pins are usually plated with a thin layer of gold, if you scape it off with sandpaper you will expose the copper core to air causing corrosion. It may improve the connection in the short term and cause the board to fail catastrophically later.

Use a hard red rubber eraser or a soft brass detailing brush to polish the pins. Some people swear by the fiberglass pens. Just don't use a hard abrasive like sandpaper.

The above is also why you don't use sandpaper on leaf switch contacts.

ken
 
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