TheShanMan's Defender restoration - New repro wiring harnesses!!!

[SirPeale]

Excellent.  Well...not excellent that there are problems, but good you found what they are.  I've been eagerly awaiting your post.

Possible to clean the legs on the ROM chips?  Replacing them is certainly necessary, but perhaps he could limp along for a bit with cleaned ones?

[TheShanMan]

Yeah, I was kind of unimpressed by the job that the fiberglass pencil did (and yes, I did clean the rom chips). I imagine it helped, but I was expecting the "after" to be much better than the "before". Hopefully the ROM's aren't too expensive. I didn't see defender roms listed at hobbyroms.com, and it wasn't clear to me from looking at that site if the prices listed were for entire sets or individual roms or what. In other words, I wondered if I'd be paying about the price listed for a whole set, or that price times 11. If you think they all ought to be replaced, I'll proceed with that plan. I'll contact him to see what a set will run me. Would you prefer that I have them shipped to you? Or should I have them shipped to me, and you'll just ship my boards back since you already know that's the issue?

Interesting that you found a chip that was so hot. At one point I touched every chip on the cpu/video board and not one chip was hot.

So what does "no problems" mean? Are you suggesting that the game booted up with no apparent symptoms? If that one chip wasn't working, wouldn't there be noticeable symptoms?

Thanks so much for your help - I can't say that enough.

[RetroACTIVE]

Excellent.  Well...not excellent that there are problems, but good you found what they are.  I've been eagerly awaiting your post.

Possible to clean the legs on the ROM chips?  Replacing them is certainly necessary, but perhaps he could limp along for a bit with cleaned ones?

Well the legs are just about falling off on some ROMs... they are just about beyond saving...  and would become an issue even if they weren't faulty to begin with.

[RetroACTIVE]

Your ROM board is fine.. It functions perfectly in a known good system.  With a good set of ROMs, your ROM board is good to go. ... your CPU has the faulty IC... I will replace it tomorrow and see what goes.

[TheShanMan]

OK, gotcha. I was thinking you tried my complete board set.

[Neverending Project]

 

It's always great to see progress being made. Nice job.

[TheShanMan]

As you can imagine, I'm super excited about progress! I didn't buy it to have it collect dust in the garage.

Ordered a new rom set from hobbyroms.com this morning. $40 shipped is a much better price than I was fearing it would be.

Got a little advice from Retro on what to look for in an oscilloscope. I want to get one so I can graduate to diagnosing board problems myself since I'll definitely be buying more arcade games. Back in the day, I was an embedded systems guy (hardware and software), but last time I did that was over 10 years ago so I'm quite rusty on this stuff, and haven't been sure what to look for in an o-scope. I'm excited to get the scope and get my next game (and almost WANT it to not be working!) so I can get busy with some hardware troubleshooting. I'm happy as a windows software engineer, but I do miss hardware, and this is a good opportunity to satisfy some of that craving.

[beerbarrel]

I did not see those roms on his site. Did you have to ask for them?

[TheShanMan]

Yeah, you might have noticed that it says they have more than what's listed. Shoot 'em an email and they'll give you a quote.

[RetroACTIVE]

Well unfortunately I have no 393s in stock... so the first round of CPU fixes will have to wait a bit.  In the mean time I will replace all electrolytics (CPU, Sound, ROM and I/O), install the lithium upgrade and a few other tidy up type things.

[Mauzy]

As you can imagine, I'm super excited about progress! I didn't buy it to have it collect dust in the garage.

Ordered a new rom set from hobbyroms.com this morning. $40 shipped is a much better price than I was fearing it would be.

Got a little advice from Retro on what to look for in an oscilloscope. I want to get one so I can graduate to diagnosing board problems myself since I'll definitely be buying more arcade games. Back in the day, I was an embedded systems guy (hardware and software), but last time I did that was over 10 years ago so I'm quite rusty on this stuff, and haven't been sure what to look for in an o-scope. I'm excited to get the scope and get my next game (and almost WANT it to not be working!) so I can get busy with some hardware troubleshooting. I'm happy as a windows software engineer, but I do miss hardware, and this is a good opportunity to satisfy some of that craving.

Is this shareable information? Im also wanting to get into board work (gonna go to college to be an Electrical Engineer. Might as well star a little early...)

[TheShanMan]

Awesome! I loved my EE college program. It wasn't a dislike for hardware that caused my career shift. It was just liking windows software development more. So I hope it goes well for you. Stay focused!

And of course it's shareable:

25MHz or better 2 channel Tektronics.... can't go wrong.  I borrow a portable LCD digital nice for debug in cab... but the good old fashioned CRT Tek is great for the bench.  Ebay or Craigs is fine 200 bucks tops with probes.

Hope this helps
Jim

[Mauzy]

Awesome! I loved my EE college program. It wasn't a dislike for hardware that caused my career shift. It was just liking windows software development more. So I hope it goes well for you. Stay focused!

And of course it's shareable:

25MHz or better 2 channel Tektronics.... can't go wrong.  I borrow a portable LCD digital nice for debug in cab... but the good old fashioned CRT Tek is great for the bench.  Ebay or Craigs is fine 200 bucks tops with probes.

Hope this helps
Jim

Cool. Ill keep my eyes out for something along those lines. I've tried my hand at software. Granted it wasn't anything sophisticated, but I seem to prefer something I can hold in my hands. That and all that text was hell on my eyes. Definitely can't have one without the other though!

[Neverending Project]

...I'm excited to get the scope and get my next game (and almost WANT it to not be working!) so I can get busy with some hardware troubleshooting. I'm happy as a windows software engineer, but I do miss hardware, and this is a good opportunity to satisfy some of that craving.

Well, it just so happens that I have a System II cabinet with some video PCB problems that are just begging for some "probing". It's a win-win situation... you get to buy a scope, learn how to use it, and get practical experience on debugging an actual PCB - I get my game working. 

[TheShanMan]

Have a cab you want to trade me for my services?

[RetroACTIVE]

Just a quick update...

Got the replacement IC installed... but that wasn't the only thing wrong...  Also found a bad 74153 so I replaced them all (4) since they were of the same date code.  Now when the unit comes up I get the distinct color bars with some rug artifacts... its no longer a white screen of bars... I'm actually seeing color... this is a good thing... not working yet... but a definite improvement.

- Watchdog circuit fixed.
- Reset circuitry checked out ok...
- The 12MHz, 6 MHz and 4 MHz clocks are working as they should.
- Not sure about the color RAM but I think its fine... (besides that would not cause this latest behavior)
- Appears as if the Data bus is corrupted (video RAM side), I've yet to check out the LS374 latches on the RAM address bus to prove this... but this seems highly probable

 

[TheShanMan]

Man, there's a lot going on with this board! I'm glad I sent it in as I probably wouldn't have had much hope figuring out all of these issues.

At least my suspicion that there was a watchdog problem was right.

Excited to see the progress, and as always, I appreciate what you're doing!

[RetroACTIVE]

I believe I confirmed my suspicions with the 374's this evening... I ordered a couple of tubes of them earlier this week and they should be here by now  .... anyway when they come in... I'll let  you know the prognosis ... I'm hoping this is it.  The last thing to worry is the CMOS RAM... I don't want to remove it until I'm sure it needs to be fixed... that will come after the board is actually running of course.

Also got replacement ROMs yesterday... left the ROM board at the office DOH!... so I didn't get to test them until this evening.

Sorry this has taken so long... had a couple of project deadlines at work and I was quite low on parts as I've fixed a few of these things and have not restocked in a while...  I also decided to replace a few questionable IC's (rusty,crusty,...etc)... this board sat in a barn for 8 years and I believe moisture got the best of it... so I tried to clean things up as best as possible.

However... I'm thinking just about done with this old fellow....
 

[TheShanMan]

Retro reported to me that 2 of the new ROM's were bad, so we gotta wait for those 2 to get resent.

Even though I'm overloaded with other projects right now, I felt a compulsion to get a little work done on the defender today. Installed my new t-molding and vacuumed it out really good. I still need to replace the front lower particle board panel that has moisture damage, and I need to clean up and touch up the artwork. It's in good condition for 28 years old so I don't think I'll be completely repainting, other than the top and back since they're straight black, and don't look nearly as good as the sides.

Bummed about the delay caused by the bad ROM's because Retro seems to be so close to done, and I'm itching to play. But a few more days won't kill me, especially when I have some stuff I need to do on my '66 mustang (my other time sink of a hobby).

Oh, one other bummer. I never looked closely at the coin mechs, but there is only one complete mech, and I wonder if it even works as is - I know the PO had it on free play and there's no coin box. It's taken a hit from moisture too, so at the very least I'm going to have to take it all apart and clean it up. Anyone know how hard it is to get a williams coin mech? I'd like to get 2 working. I understand the middle one was actually used for Susan B. Anthony dollars, and mine is blocked - I imagine it became fairly standard to have the middle one blocked as those dollars became less common?

[SirPeale]

They're just regular coin mechs.  I've got a bunch of quarter mechs for you.  $5.00 each.

[TheShanMan]

Cool! I don't know how many you have, but unless you are low enough that you might run out, I'll wait until I can get my existing mech cleaned up and tested before I buy, so I know if I need 1 or 2.

I don't know if my mech is token or quarter, but I actually would want to convert to tokens. Can these be converted or would I have to buy other mechs? I checked the "convert coin mechs to tokens" thread and I don't think these mechs are there.

[RetroACTIVE]

HOLY CRAP!  This board is full of problems...

The good news is that it now starts up... rug pattern is there... and it goes into the attract mode (at least you can tell by the smattering of pixels)... but it still is not completely up yet!

The bad 374s were the remaining problem holding up the start up sequence and keeping all 4 status leds on on the ROM board...

Now I believe its the 165's (video shift register circuitry) that is screwing up the works....

This is with out a doubt the most messed up board I've dealt with in a while... its not obvious like massive corrosion or physical damage.. or typical easy failures... but many many parts are faulty on this bad boy...

... almost there
 

[TheShanMan]

Oh my gosh. I would have been way over my head if I had persisted in trying to fix it myself! You're a God-send, Retro!

[RetroACTIVE]

Well ALRIGHTY THEN!  Its done!

- All inputs and sounds check out.
- CMOS passes CMOS test... (I've not yet put the battery in and saved  a high score... )
- The last thing was the 74LS139 (1 of 4 decoder)... keep an eye out for failures where it looks like the rug pattern twinkles and the attract screen has very little data on it (I could barely see the bottom of the Defender text flashing)... this behavior is indicitive of the 139 failure.

I will put the battery in and see if it retains scores\coinage... I think it will be ok... I'm feeling good now!
I will run a full blown burn in (24 hrs) with entire ROM set before I say good to go back to TheShanMan!

[TheShanMan]

I am very excited! I'm sure you'll be happy to be rid of it - you probably would have never guessed that you'd be in for all of this when you expressed willingness to work on it. I assume you don't have a tracking # for the 2 replacement roms, but I guess we should cross our fingers for them to arrive by the weekend. It would be too cool if I actually get to start playing 2 weekends from now!

I hate to keep saying this over and over, but thank you so much!!! I hope it won't be long before my abilities will be good enough that I can give back to the community in a similar way.

[TheShanMan]

How does one adjust the joystick's action? I installed a rebuild kit and the joystick just seems AWFULLY springy. Seems like it should be stiffer or the springiness needs to be dampened or something.

EDIT: Here's a video to demonstrate.

[youtube]http://www.youtube.com/v/soGBuU3J2wQ[/youtube]

[SirPeale]

Looks good to me.  At least you have that.  Mine is loose and sloppy.

[meany]

Looks like I remember it in the arcades.

[beerbarrel]

Looks good to me.  At least you have that.  Mine is loose and sloppy.

Mine is loose and sloppy too!

[TheShanMan]

OK, cool. As much as I always liked it, I rarely played it in the arcades because of the difficulty (I didn't have THAT many quarters to burn!). So I don't even have a memory of how it was back then. Thanks for the feedback guys!

[RetroACTIVE]

Ok... I still have TheShanMan's Defender boards... but they will be returning to him tomorrow...

His boards were plagued with problems... so this took a while

Initial Symptom:  White screen, board was held in reset and all 4 leds on the ROM board stay on.

#1 Tested the ROM board with known good defender CPU... no dice.  Beyond physical corrosion, many of the ROM chips were bad.  A new set was installed... ROM board tested ok...(as it seemed...ribbon cable bites us later)

#2 The Watchdog circuit was faulty, holding the board in reset.  This turned out to bad IC 5O (LS393).

#3 After fixing watchdog, no change in behavior... Observed IC 3G (LS153)... outputs appeared to be not quite at 5 v... so I replaced all of the 153s.  Now the bars are no longer pure white... there are multicolored rug artifacts but still distinct bars.

#4 Video RAM data bus is corrupted, IC 1M (LS374).  I replaced all of them (1M,3M,4M)... and BINGO!  Now all of the leds go out and the game behaves like its going into attract mode... but the attract mode is screwed up.

#5 Bad IC 4K (LS139) (2 to 4 Line Decoder), causes this weird twinkling effect on the rug pattern and the attract screen to be missing nearly all of the graphics... except the bottom of the word DEFENDER... and I mean the bottom, I only know thats what it is by its blinking effect. 

#6 Long term test proved system to be unreliable, the board locked up and after cycling power, I could not get it to come up reliably each time... I replaced the ribbon header on the ROM board and this solved the issue.

#7 I was also concerned about the CPU and Decoder ROM sockets, so I went ahead and replaced them for good measure.

Other things done:
Installed lithium kit, replaced all electrolytic caps, replaced 20 pin I/O header and cleaned up the boards in general.

This was fun... a bit wicked... but fun none the less.  A big thanks to TheShanMan for being patient and understanding, its hard fitting this stuff into day to day life.  Another good thing is I know have enough parts to help save plenty more Defenders!

 
Jim

[TheShanMan]

Is this guy awesome or what? No need to thank me for being "patient and understanding" - how can someone complain with you being so generous with your time and ability? I'm just thankful that you enjoyed it, because I feel bad enough about how this project became much more difficult than we figured it would.

Hey, at least I correctly guessed that my board was stuck in reset! I would have been WAY over my head trying to repair this myself, despite being an embedded systems engineer early in my career. But this process has helped me just about as much as you could possibly hope without being physically present, so whenever I do encounter a real non-working game I will at least feel more comfortable tackling it. And you have certainly inspired me in that respect, Jim!

Of course, this will also make me more discriminating when it comes to buying games with apparent moisture or corrosion issues!

Thanks so much Jim. Can't wait to play Defender!

Restoration will continue after I get the boards back. Still plenty to do on this prized possession!

[RetroACTIVE]

Well... I win the ---meecrob----bag-of-the-year award... I sent the boards back to TheShanMan and forgot to put his 4164 adapter back in the box!  So here he is excited and ready to go... and then  dummy forgets to put everything back in the box!

...this guy.... not so awesome 

[TheShanMan]

No, you're too hard on yourself! With all the stuff of mine that you had, it's no surprise that something so little got overlooked. Remember when I PM'ed you a checklist of items to help prevent this very situation? Well, I forgot to include the adapter in that checklist, so I'll take some of the fault too.

So don't anyone let this guy convince you that he's anything less than awesome, because I certainly think he's awesome for what he's done for me, and this minor glitch doesn't knock my opinion of him in the slightest.

[SirPeale]

That's the one I made for you, right?  Both you guys handled it, how does it feel?  Still in one piece?

[TheShanMan]

Yes. Seemed to be perfectly fine to me, given the limited amount of time I messed with it before shipping my boards off to Jim.

[RetroACTIVE]

That's the one I made for you, right?  Both you guys handled it, how does it feel?  Still in one piece?

I like it... way better than using wires.   What kind of header/housing did you use..amp or molex?  The ones I use have a more severe locking mech and are very difficult to unplug... I like the ones you use, they are just right.

[SirPeale]

It's a Molex header with pins from ITW.  It's pretty compact.  I expanded on previous ideas and came up with that design.

[TheShanMan]

While reinstalling my boards, and since I can't play it yet , I figured I'd clean up the power supply board. Well, the transformer part of it. It had a switcher in and no PS PCB when I bought it, so these pictures reflect that. I've bought a PS PCB off of ebay that I'll get rebuilt and installed so I don't need to use a switcher any more, but that's a project for another day.

How do you guys like the before vs. after? A little better? 

BTW, I decided not to paint the particle board because although you can't see it in the pics here (my full size pics show it), there is a "TESTED" stamp and a "JUN 26 1981" stamp on there. I like seeing that on there.

[SirPeale]

It's cleaner!

In the interim while you're waiting for that adapter to arrive, you can pull the wires not used out of the harness and wrap them with electrical tape.  Easy to pull out, you just need a tiny flat bladed jewelers screwdriver.