Laser Cue - IT LIVES

[ChadTower]

Well, since the guy flaked on the MAME cab I was building him, that goes back burner for now.

Up next, Laser Cue. 

I don't have any pics just yet, can't find the camera.  I should have those up in the next couple of days.  I picked this up for free, in pretty good shape, from a woman on Freecycle.  It had been in their basement rec room for 15 years and nonworking for 13.  The woman wanted it OUT, while the husband insisted it was worth a lot of $$ and wanted me to pay.  They fought and she won.  I got it free. 

[ChadTower]

[ChadTower]

The yellow pin you see to the left is Rack Em Up, a pin I scored at a yard sale last year for $75.  Pretty good shape, just needs refurb work to make it reliable again, and of course a shop job.

What you see here is a wire I noticed while reconnecting all the molexes.  Must have been cut when the owner was taking off the head so I could move it.... nice of them to tell me.  I'll put some quick disconnects on them and some tape numbering the connects so no one confuses them later on.  The wires you're looking for are yellow and in the foreground.

[ChadTower]

Oh, forgot the backglass, I can get pics of that and what I need to do with it in the next couple of days.

[arcadefever]

  you can fix pinball !!!! that nice , whaaaaaaaaaa never saw the inside before ,
it look really good !!!!!

[Bones]

whaaaaaaaaaa never saw the inside before ,

Yeah me either. There is much more electronics in there than I expected.

I can't believe you got it for free Chad, you might actually be a nice person in real life to have scored this one.

[SirPeale]

Yeah, the insides of pins are pretty complex.

Been learning the fine art of pin repair at work.  Fun stuff.

[ChadTower]

Bah, I'm actually very amicable in person, though I had to stand there while that couple fought a hard one over my taking the pin.

The wife was going to win, it was always obvious.

This era pin, and early solid state, is actally not that complex.  It's happy fun easy cake with simple frosting compared to the Twilight Zone I spent the summer on...

[Bones]

I watched Twighlight Zone but never participated, I just wasn't all that interested in pinballs. Starting to think differently now though.....

Keep the pics flowing, this stuff is all new.

[ChadTower]

I wonder if I should replace that giant cap in the wiring shot... that's gotta be wonky by now.

[ChadTower]

Cut the tips off those wires, stripped a bit of insulation for a clean end, put some insulated QDs on them, and put bits of tape labeling each end and its mate so there won't be confusion later.

Not sure why they are even there, maybe a hack repair job at some point.  Don't see much sense in having to cut two wires to remove the head when there are tons of molexes with tons of wires in them to avoid that.

[SirPeale]

I wonder if I should replace that giant cap in the wiring shot... that's gotta be wonky by now.

Quite possibly not.  Caps like that don't go that often.

And here's another piece of trivia: they don't make caps like they used to.  Really.  There are 30 year old caps that work better than brand new ones.  That's where a cap tester comes in handy. 

With older monitors. before I just aribitrarily replace every cap on a board I test them first.  A lot of the time they're just fine.

[ChadTower]

So what is up with the Atari big blues?  Just a bad choice of part?

[ChadTower]

Just spent an hour trying to figure out where the hell the power cord is supposed to come out of the cabinet, since mine was all inside.  Finally found some other system 7 photos, apparently it goes through an obscure little notch between the head and the body.  I had to remove the head to put it in there.  Annoying.

In the process, though, I found one more power molex set that hadn't been connected.  Glad I found that one.

[ChadTower]

Got this sucker powered up... very wonky behaviour.  I was able to determine, though, in the process:

• Speakers are working, got it to play a few sound effects.
• GI works, if not properly, but the playfield GI and backgoard GI lit up.
• Didn't get any response from any of the op buttons or anything in the coin door.  Mechs are absent.
• Wasn't able to coin it up or start a game, somehow got one flipper to attempt to flip but that was it

Tonight, I'll read through the schematics and check all the fuses.  Want to make sure they are all the right type/rating and all have continuity.

[SirPeale]

So what is up with the Atari big blues?

[ChadTower]

Big blue = Power supply filter cap in games like Centipede, Asteroids, etc... Atari cabs of that era.


So I checked the fuses on the sound board... all good, right ratings.

Power board:  solenoid fuse = dead.  Must replace, obviously a problem.  HV fuse = wrong fuse.

The HV fuse lists on the schematic as a .25a SB.  What is in there is a .5a SB.  That seems like such a tiny difference, but it is a full 100% increase in rating.  Is that acceptable, or should I swap in a correctly rated fuse?  They're cheap.

[SirPeale]

You should always use the correct rated fuse.  Their function, other than being a power conduit, is to protect the device from a massive power spike.

So...yeah.  Doubling the amount of amps that your board will take can be *very* bad.  It's rated @ .25A for a reason.

Now...if there's nothing wrong with the board, likely nothing will happen.  The fuses are there for the trouble times.  Since this is a pin in repair...DEFINITELY use the correct rated fuse.

Too bad you're not closer, I've got about thirty boxes of .25A SB @ the shop.

[ChadTower]

Heh, thanks for the offer, I'll just snag some at Radio Shack.  I need a couple others too anyway.  The flipper power board fuse turned out to also be the wrong fuse (7a rather than 4a as listed).

So, whoever used to work on this didn't put in the right fuses.  Surprising, huh?   

[SirPeale]

Big blue = Power supply filter cap in games like Centipede, Asteroids, etc... Atari cabs of that era.

Ah, gotcha.  Power supply caps go a lot.  We use a lot of Peter Chou power supplies.  The caps go all the time.

[ClubNinja]

Not sure why they are even there, maybe a hack repair job at some point.

[ChadTower]

Yeah, I've been going so far with general good electronic repair knowledge, rather than Marvin3m.

[ChadTower]

So, I went to dumbass Radio Shack tonight... they have two of the fuses I need, but of course no 0.25A SB.

Not sure where to get it without ordering, and who wants to ship that?

[ChadTower]

Crap.  I replaced the Solenoid and flipper power supply fuses with the proper ratings... turned the machine on, and immediately saw smoke coming from the solenoid driver board.  Turned it off FAST, looked at the solenoid fuse, and it's kind of melty.

I think I've uncovered a problem.

[ChadTower]

So... dumb.  If you look here at section 2a, you will see a warning about making sure the physically matching, but different color, connectors are properly matched.  Sure enough, I had them reversed, and the solenoid voltage to the +5v logic line.

---steaming pile of meadow muffin---.  I wonder how many things I fried.

[SirPeale]

---Cleavland steamer---.  I wonder how many things I fried.

Doing it so quickly, maybe nothing.  Maybe a transistor or two. 

[ChadTower]

That is what I'm hoping, though since that fuse was burned before, now I wonder if I burned it the first time without knowing it.  Maybe this is why the machine hasn't been booting properly.  It IS 50v through the 5v line.

[ClubNinja]

I cringe with pain. 

If you let smoke out of that sucker then something's got to be damaged.  Even quickly, I'd suspect a few cooked transistors.  Still very fixable (and a cheap fix at that).  I think you'll get out of it without too much trouble though.

[ChadTower]

My fear is this:

50v though a 5v line can cook a lot of things in a hurry.  I fear that the damage is not isolated to the driver board.  I fear it may have shot to the audio board and the mpu as well.

I'm going to verify the power supply is good next, and from there, I'm not sure of the next best step to take.

I feel awfully stupid.  Two pin projects, two times starting off with self inflicted damage.

[ChadTower]

An RGP post led to my being pointed to an old RGP post that had been reaped by Usenet but someone had on their hard drive (phew).

I'm going to paste it here since it is very much in context and applicable.

Now that I read through it better, looks like this info is paraphrased very closely in Marvin3m's guide.  I'm putting it here anyway.

Subject:

[ClubNinja]

I saw that post, very informative.

As an unrelated request, be sure to peel that ugly op/vendor sticker off the apron next time you're working on that.  There's one on Bobby Orr in the same place that's giving me heck in trying to remove it.  It drives me nuts.

[ChadTower]

Heh, that is so low in priority now.  I'm not even really bothering with the coils or playfield until I get this sucker working.  With the TZ I shopped it and then wanted to get it working... this time, other way around, so I can actually play the damn thing once it is shopped.

[ChadTower]

All of my research bears out the same conclusion:

I likely fried most of the ICs on the MPU and the driver board. 

Original replacement boards are common, though, and there are newly designed drop in replacements as well.  Getting a good set of either is going to run close to $300.  I don't have that type of cash for a game project until spring, so this project will have to wait until then for real completion.

[ChadTower]

OOOH... just got an offer from someone who wants to set up a nice test bench for doing system3-7 repairs.  He's offering to repair my boards at cost of parts if I allow him enough time with my boards to get the test bench up and running.  I'm not in a hurry with this, so I may well take him up on that.

[ClubNinja]

Take him up on that one if you don't plan to repair the boards yourself.  Very nice offer.

[ChadTower]

One of the chips on the list above has like 7000 very close pins.  I couldn't solder a socket in there if my life depended on it.

[ChadTower]

[ChadTower]

Not mine, but worth a peek.

[ClubNinja]

The NOS backglass certainly helps.  That's a good looking game right there. 

[ChadTower]

Better looking that mine, definitely.  Mine has some playfield wear that may end up a candidate for my still theoretical printed vinyl/mylar playfield patch technique.

Plus, my backglass needs love.