Arcade Collecting > Restorations & repair
TheShanMan's Defender restoration - New repro wiring harnesses!!!
TheShanMan:
--- Quote from: Peale on September 01, 2008, 12:47:32 am ---The RAM may very well be part of the problem. Check the ROM board, there are four LEDs. What do they do when the machine is booting? You can open the coin door and look inside to see what it's doing after hitting the power switch.
--- End quote ---
The LED's come on and stay on. If the ram may be part of the problem (even though none are hot), how soon will you have them available? I'd like to keep this ball rolling as much as possible so I can get it up and running at the soonest possible time, so I would love to order them from you but I hope I won't have to wait long.
--- Quote from: Peale on September 01, 2008, 12:48:34 am ---Another thing to consider is the damage from the battery. It looks like the traces may be eaten away, you may have to run some jumper wires.
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I'll try some continuity tests to see how it is.
Did that new monitor pic tell you anything?
Level42:
--- Quote from: TheShanMan on September 01, 2008, 01:17:01 am ---... I'd like to keep this ball rolling as much as possible so I can get it up and running at the soonest possible time, so I would love to order them from you but I hope I won't have to wait long.
--- End quote ---
You'll need to be a bit more patient my friend, this sounds like a problem on the mainboard to me. You'll have to check if the watchdog is constantly tripping the reset of the CPU. From there, you may find lot of problems that you'll have to be experienced in finding in board errors for.
There's no "magical solution" to a problem like this. I doubt it's the RAM because the board doesn't even come up right now. I have the same problem with a Defender I'm working on here right now.
If you're really in a hurry, I'd reconsider the new multi-williams by JROK. Although I can understand why you want to try to repair the original hardware first.
TheShanMan:
I understand. I just mean that I hope to avoid unnecessary delays. It's not like I'm sticking this in the corner to deal with at some later time. That's all.
If you're having the same problem then I hope you'll be posting your findings.
I'll look into the watchdog circuitry. I saw some info on that in the manuals, so hopefully it's enough to help me do some checks. I don't have an o-scope so unfortunately I'm limited for any tests that need one.
I appreciate all the hand-holding. I've already learned a lot!
BTW, I checked for continuity of the ground at the batteries and various other parts of the board, and it doesn't appear that corrosion has broken any of the circuits.
RetroACTIVE:
+ It appears that your system isn't even properly initializing... this looks more like a voltage/connector issue at the moment. Or your switcher's rise time is way too slow...
+ If it were a RAM problem... you would at least get a rug pattern...
+ Check voltage on each of your boards... (not at the power supply)...
+ Looks as if this unit has had some moisture issues... you need to check the ribbon cable that connects the ROM board... pull it out... clean the pins and put it back on...
+ Your batteries may not even be working since it appears as if the holder is way corroded. They are most likely not the cause of this issue you are having. The batteries are there to provide back up voltage to the CMOS RAM.
:cheers:
SirPeale:
--- Quote from: RetroACTIVE on September 01, 2008, 11:03:10 am ---+ If it were a RAM problem... you would at least get a rug pattern...
--- End quote ---
The rug pattern is part of the RAM test. If the RAM is bad, you won't get proper rug pattern.
I had one bad RAM in my Defender, and got yellow bars but not a bit of rug pattern. Replaced that RAM and finally was able to go into onboard test.
*DEFINITELY* check your voltage on the board. I'm sure your power supply needs recapping. Remember...30 year old caps aren't your friends.
*DEFINITELY* clean any socketed chip legs. If you don't have a fibreglass pencil, get one. BE GENTLE. Clean both sides of the legs.
*DEFINITELY* check solder joints on the PCBs as well as connectors. Williams connectors are known to be problematic.
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