Arcade Collecting > Restorations & repair
TheShanMan's Defender restoration - New repro wiring harnesses!!!
TheShanMan:
Yeah, I've been doing exactly that kind of tracing. I got the watchdog circuit disabled (there is a spot where the manual directs you to cut a trace, and then ground a pin) but it's still not booting. I haven't tried actually shorting the reset pin to 5V yet though.
One thing that seems odd to me: as I mentioned previously, my switching PS intermittently makes a fairly high pitched noise. I was just watching my monitor after disabling the watchdog circuit and this is what I saw: Black initially. Then it went solid yellow. Then as I heard the PS make that noise, the video would simultaneously flicker to solid red, but the transition from yellow to red had kind of a garbled look. The changes in the video picture would track as the PS noise came on and off. Could this be an indication of a PS problem? Do switching PS's commonly make very audible, high pitched noise?
I can try to make a video if this isn't descriptive enough to mean anything to you guys.
Yeah, the multi-board is a good backup plan, but if at all possible I'd rather stick with original hardware (in fact I wish it had the original PS).
And Peale, I've been spending a bit of time searching through the RGVAC archives. Finding some similar symptoms, but nothing that has told me definitively what the cause is.
Retro, I'm not at this point yet, but I wonder if you're willing to have a look at my boards as you've done for someone else here? That would be another nice backup plan, though I totally understand if you'd rather not.
Maybe I need to start watching CL for an o-scope! Would you guys consider this to be an essential tool for anyone who's getting into arcade game collecting? Or can you often get by without one?
Kevin Mullins:
Do you have a CPU you can swap out ?
And you may also want to take a look at any crystals on the boards for damage etc.
TheShanMan:
No extra CPU. The crystal's case is somewhat rusty (you can kind of see it in the close up picture of the board I posted), and I've already wondered about the clock signal. I wish I had an o-scope to check it! Beyond rust on the case, I'm not sure how I'd check for damage.
TheShanMan:
Here's a video of what the monitor does in sync with the PS noise, as I described two posts back. I tried to pick up the noise coming from the PS, but it doesn't get picked up in the recording.
Also, this doesn't look exactly as I described before (it seems like it changes every time! :banghead:), but you get the idea with the flickering, which is in sync with the noise coming from the PS.
[youtube]http://www.youtube.com/v/lIn-8hsJN0I[/youtube]
RetroACTIVE:
--- Quote from: TheShanMan on September 01, 2008, 06:24:05 pm ---Retro, I'm not at this point yet, but I wonder if you're willing to have a look at my boards as you've done for someone else here? That would be another nice backup plan, though I totally understand if you'd rather not.
--- End quote ---
Not a problem... I'm free right now.. I've got another person's stuff but am waiting on parts... but its not a rush job.
I still think it's a power issue... your switcher looks like poo ;) (not that its an indication of a problem...but it certainly leaves one to wonder). Remember the reset circuit uses +12V (unregulated)... but with switcher conversion, you are using the +12V output of your supply. If the output of your switcher is noisy ... you are going to be SOL... Do you have an extra switcher lying around you could swap out just to be sure? The DVOM does not give you the complete picture when it comes to the supply voltages... this is where a scope helps.
If you send your boards to me... I can do a complete once over... and upgrade to 4164 if you like. I have a few spare 4116's kicking around I can pop in there to get it running too (if RAM becomes an issue). As Peale stated before... the 4164 upgrade is almost a must if you want your Defender to run without issue... Running with the 4116's you will find they will begin to fail here and there and you will be chasing problems until you've replaced them all anyway...
:cheers:
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