Defender: Hacked Harness / Switching Power Supply

tb lilley

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Ok. I'm expecting to take delivery of a Defender in a couple of days time. Not seen it in person, just a few photos. Cab doesn't boot.

Looking at this, it appears to have had a switching power supply installed. It's not a neat and tidy job either as it looks like the wiring has been horribly hacked ....

e64fed8c.png


First job will be to rebuild the linear power supply and rip that switcher out. But ... does anyone know where I could acquire the correct wiring harness to replace the hacked one?
 
I don't see what's so "horribly hacked" about that. Looks pretty neat compared to some I've seen. Looks like the control panel harness was replaced, but it looks like a clean job. I wouldn't worry about replacing it.

The switcher appears to be plugged into the existing harness - other than the 120vAC input to the switcher, it looks unhacked.

I would suggest you NOT fix the original power supply. The Defender original power supplies were terrible, awful designs with no over voltage protection. Having seen the aftermath of literally exploded RAM chips after one of those goes, I would not want one anywhere near my games. If you *really* want a linear power supply, then use a newer one, like from a Stargate.

The switcher, provided it's working, should be fine, and you should be able to get the game to run with it. The only problem with using a switcher in Defender is the occasional loss of NVRAM data due to the powerdown sequence of a switcher. Get the game working first, then worry about tracking down/fixing up a linear power supply if you want.

-Ian
 
That is one of the better hack jobs that I have seen. You will also need to know if 4164 RAM has been installed in the MPU or not.

Which part of the hacked wiring do you want? The Trans to 4J1 is hacked and 4J2 to the MPU, ROM board, Sound board is also hacked. 4J3 appears to be intact from the pic that I see.
 
Which part of the hacked wiring do you want? The Trans to 4J1 is hacked and 4J2 to the MPU, ROM board, Sound board is also hacked. 4J3 appears to be intact from the pic that I see.

You've got good eyes for this. I knew you'd chime in. I honestly don't see the other mods, but I do see the transformer connector now.

Dokert's the man when it comes to Wiliams wiring harnesses.

But yeah, that's a really, really clean mod. You should have seen my Robotron. Here's a couple of pictures that I took of the control panel harness in that game:

http://i250.photobucket.com/albums/gg280/RetroHacker/cp_connector.jpg
Oh look! The control pannel connector. How... nice.

http://i250.photobucket.com/albums/gg280/RetroHacker/cp_ratsnest.jpg
Look at this wonderful control panel wiring job!

Whole thread is here, if you want to see how bad a Robotron can be:
http://forums.arcade-museum.com/showthread.php?t=88159

-Ian
 
That is one of the better hack jobs that I have seen. You will also need to know if 4164 RAM has been installed in the MPU or not.

Which part of the hacked wiring do you want? The Trans to 4J1 is hacked and 4J2 to the MPU, ROM board, Sound board is also hacked. 4J3 appears to be intact from the pic that I see.
I'd like it to be as original as possible. I've just sold a Streets Defender. That required a full linear power supply rebuild and I was comfortable in doing that. Also switched the RAM for 4164 (modified the power before it entered the main board).

My intention with the Williams is to rebuild the power supply so that it's up and running again. After that the first thing I'll need is the correct harness from the transformer to the linear power supply. After that, the correct harness that takes the power from the linear ps and away to the boards.

I'm quite reassured that you don't think the hack job is too bad - that's good to know. But I really do want that switcher out and the linear working again.
 
I'm gonna bug you for a Stargate harness within the next couple months if that's cool. Gonna do a scratch-build on the cab with me Pops.
 
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