Comet repair job

shardian

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The guy who bought my Lethal Weapon has commisioned me to repair/shop his Comet pinball. This thread will chronicle the process, and serve as a journal for my own use (and your entertainment). Owner says that many of the GI lights don't work. He also said the million shot kickout doesn't work.

It is in overall decent condition cosmetically. The playfield is of course yellowed/stress cracked wherever there is no mylar. It appears to function with the exception of all the solenoids (fuse).

I found a few issues right off the bat - a burnt connector and a fried looking driver. I pulled the board and found this crap. Ladies and gents - that is SINGLE strand wire to repair a solenoid driver. Not solid core wire - I mean literally a single strand of wire you that yout would pull off a normal stranded power wire.One of the leads wasn't even connected, and it appears the sheathing had fused on two of the wires - probably shorting.

I haven't downloaded schematics yet, but I can assume that the J7 connector is GI. The connector was apparently replaced, but not the header. That is a big no-no on Williams games, as you can see.

On the power board, there is a hack repair in the lower right. It looks like a connector was bypassed. I'll know more after reviewing schematics. This repair may be okay. We'll see.

I was hoping for a simple issue, but instead I get some hack work to fix up. Dang...
This is why we don't quote flat rates before seeing the damage folks...hourly or nothing.
 

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Speaking of that connector - that leads me to my tip of the day.

Always take the time to label all of the connectors if they aren't already (these weren't). Also make sure the keys are intact too. If not, either replace the key or mark pin #1 by marking across the pin header and the connector in the same place so the marks always have to line up.

2 extra minutes here can save you an 'oh shit, where and which way did this go' later.
 
Wow, what the hell happened in that first pic? That's the worst solder job I've ever seen. Looks like a few traces might be shorting as well. Looks like there's solder everywhere but around the actual component.

I always wondered why people used markers on their connectors. I've always just cut labels out and taped them on with electrical tape. I guess I'll have to steal your method :)
 
I just use a sharpie as well, I put the connector number on the side and I just put a little dot on top of the connector to signify that the connector faces up towards the roof.

I tried the tape method but its more work and taking the tape off sucks. Some hardcores probably want clean connectors, but I could care less. I'd rather have them labeled so I don't screw something up, plus when you go to remove them the 2nd time it makes it super easy..
 
Well what most likely happened to cause that mess is that the solenoid fuse was supposed to be a 2.5 amp fuse. I just pulled a dead 5 amp out of the holder. Bad things happen when you double the fuse rating.

I guess that brings me to my next tip: ALWAYS pull all fuses on a game you get - even if it works perfectly. You need to verify what is supposed to be in there is actually there. I made this mistake on Lethal Weapon. Even though everything worked fine, there was a 10A fuse in the 5A solenoid fuse holder. The result was a badly cooked transistor that almost melted through the board - kind of like what you are looking at in that pic.

And for the record, one of those puny wires simply fell off when I touched it. That fried transistor was for a jet bumper. It was jumpered to an unused (below) transistor, and the funhouse kickout TIP122 (above). The funhouse kickout is allegedly the one that didn't work. It's pre-driver appears to be burned up a bit.
 
That pop bumper's driver and pre driver are dead. I figure the 7402 chip is also crapped out. Since it's already in a socket, I'll go ahead and throw one in to replace the whole drive train (special coil, so no CPU control PIA to blow up).
The resistors in that circuit are also testing way out of spec. I'll pull them out to verify, but resistors on neighboring spec circuit coils test correct in circuit.

Now why did this cook you might ask? The coil is shorted. Not only is is shorted, but it is frozen in the up position. I bet that puppy got smoking hot when it tried to pull in the plunger.

The dunking booth coil is testing open, so it might be bad too. Everything else on the game is fine.... well other than the burnt connector I've already mentioned. The 2 watt resistors up there that come off of that connector have cold solder all over the place which will be reflowed.
 
What makes you think that?

It's been replaced before, along with the driver/pre driver. Both drivers are fried. It is a fair assumption that the 7402 is bad again too. I suppose I could test it, but I already have a chip on hand to put in a socketed location. ;) That's easier and quicker, and doesn't take any time for me. I hate testing chips.

The coil was pretty darn melted. It was locked in the up position because the sleeve was full of molten plastic. :eek:

...but since you said it, I suppose I'll test it now. Damn you Lindsey.
 
Board repairs done, and the game works fine now. Now I just have to wait for a a parts order for the two bad coils.

The GI was also out, which apparently is a MAJOR issue on Williams of this era. Just another one of those funny little 'passes' Williams gets I suppose. ;)

After 15 minutes of on time, the connector I replaced along with the 2W resistors below it were hot. The reisistors were hot enough to burn me if I lingered too long. There is some hard to find automotive relay that is bad for the backbox GI. I also need to do a few mods to lower the heat in the GI circuit for long term reliability.
 
GI issue was the relay. I saw tons of people on RGP freaking out over this relay, wondering where in the world to buy it. It had me worried it was obsolete or something.

However, it is just a simple 12V relay, so that didn't make sense. I went to NAPA this morning with the relay since it said "Bosch" right on it, and asked for a replacement. One minute later I walked out with a brand new relay that works perfectly. Methinks I should make some money from some RGP folk who apparently lack for common sense. :cool:

More pics huh? When I get my parts order in and start tearing it down I will post more. I meant to take a pic of my repairs, but got impatient and installed it instead. I try to avoid jumpers whenever possible. I made a hook out of a cap leg to repair one trace. You just scrap back the trace about 3/8", use pliers to 'hook' the end, and solder it down to the trace with the hook overlaying the original through hole. Insert the transistor and solder like it was a trace. Instant solid connection.

For the middle leg I just bent the transistor leg into a shape to overlay the trace. For the last one I was pretty much forced to use a jumper, so I used a nice insulated chunk of stranded wire, and routed it tight to the board.

I suppose I could take a few pics of the machine as-is now. Not much to look at really. My main interest was getting it operational. It's an okay game, but not one that holds my interest.
 
Hmmm... I've ran into an issue that I could use some help on.

While playing I noticed that the sound sucked. I had never played this game before, so I did'nt realize anything was wrong for a while. I ran the sound tests, and many of the speech calls were garbled. Reseating the roms seemed to make them a little more clearer. Research seemed to point me in the direction of the 1458 amp chips. I looked at them and one of them appeared to have bad solder connections. I reflowed it top and bottom and reinstalled the speech board. They were a bit better, so I started pressing on chips. During speech test, I had all of the speech calls coming in perfectly, but still a bit quieter than I thought they should be. So I started up a game. Now ALL speech calls were missing. I cued the speech test switch again, and now all speech calls are 100% missing (except for the Explosion one). It also seems that sound #1 is missing now.

Any advice from those that have messed with sys. 9?
 
Since I had nothing better to do without ordering rebuild parts, I went ahead and completely resoldered the U3 amp chip. The connections still looked kind of crappy (you know how sometimes the legs can look like they have tar or something on them?), so what could it hurt? After completely replacing all the solder and reflowing the 2 top side trace connections, I get all sounds again perfectly in testing. I started a game and everything is there. Makes me wonder if the thru hole plating was cracked. That seems to also be a problem on this era of boards. Oh, I also reflowed the single top side leg trace on the other amp.

Now that I do have the speech sounds , the dunking booth guy took about 20 seconds to annoy the hell out of me. ;) "HEY! C'MON! HIT ME TURKEY!"

I don't think the owner was even aware this game had speech, so this ought to be a nice surprise for him.
 
I had a feeling things weren't over, so I fired it up first thing this morning. As I suspected, the speech was gone again. So apparently the heat of the soldering iron is what was making it work?

As a test, I heated the speech section where the amps are with my heat gun for 15 or so seconds. Enough to get it nice and warm to the touch. Then I fired it up. Now I get constant static like sound on the speech side, and the CPU generated explosion is still the only sound played in the speech test. I'm going to order the 1458 amp chips, along with some caps in that area. It works perfectly twice now after reflowing/replacing solder on those amps, so I think it is safe to assume they are the problem.

Oh, and when I take some pics later, I have a fun one to show. I know everyone pics on DE boards for running super hot. DE has NOTHING on the lamp driver section on a sys. 9 board! When I was doing testing after running the game for a while, I was pecking at the board and feeling for heat. I pecked at the lamp drivers with the back of my index finger, and it burnt the hell out of me. It was instantaneous contact - fraction of a second. It gave me the kind of blister burn you would get from a soldering iron.

I'll add that to my list of why Williams gets a far greater rep than they really deserve.
 
Well, to be fair, these DE boards are almost a straight rip off of Williams System 11 boardsets. Take a look at them next to each other sometimes, kind of funny.... Especially the PS boards....
 
You just keep trying to convince yourself of that... :)

Wade

Stop by and pop some popcorn on this boardset then! :)

Every board set has its issues. You and I both know there is a handful of people who refuse to acknowledge that Williams also has had a few issues over the years. I will say that the WPC hardware is pretty darn nice. It even tells you which fuse popped and where to check for issues. That is pretty sweet.

I can't help but find it humorous when I dig into a Williams and find all sorts of documented design flaws. My first thought is "Hey! I thought these Williams boards were perfect!".

PS. You owe me like 2 emails. Get to it!
 
Okay I took plenty of pics for you guys. Up first are the playfield before shots. You can see where the playfield is horribly stress cracked in the clear and paint. Nothing can really be done about this. Also you can see the fading of the non-mylar areas. Other than that, there really isn't much wear. This playfield will be a great test for the treasure cove kit. If this turns out well in the hour or so I will spend on it, I think treasure cove will owe me a few free replacement spplicators. Why? Because surely many of you will rush to get the kit!

The mylar area will look great, and the kit should take out a lot of the ball swirl. The thing I am worried about is removing paint. I'll have to take it easy in those areas.

I am not doing a complete tear down on this one. Just a basic cleaning and a polish with the cove kit. No removing/polishing of any playfield parts. Well I will clean the main ramp, but that is about it. I will be putting on all new target decals, and a flipper rebuild. The left flipper has the fatigue flutter, but the right one is fine. I've always wanted to try a rebuild kit, and what better time to try it than on someone else's dime. ;)
 

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Here are some cabinet shots. Nothing much to see here. The cabinet is in pretty good shape other than a few dings and a chipped corner I have to reglue. Since it's black, I'm just using magic markers and sharpies to refill the gouges. My method on this is to hit it hard with the marker without being careful, then following up with a paper towel to wipe off the excess on the undamage cabinet. This way, the scratch gets filled and you don't have the obvious overlap mismatch black on the cabinet. It makes a much cleaner looking fix. Paint would be better, but this is good enough and really quick.

Special note here is the corkscrew ramp. These are notorious for being broken. This one is of course also broken, but I feel the game isn't worth spending $70 on. It has been previously repaired with masking tape as you can see. This repair works...surprisingly well! Just for giggles, I will spray the back side of that masking tape with matching orange paint. Then most people probably won't even notice it. If it ever breaks, you just slap a new piece of masking tape over it.

Lastly is the promised battle damage photo of my finger. That was from merely tapping my finger on the top of a driver for the lamp section. That area is below that burnt connector I showed earlier. After changing all bulbs to 47's and getting rid of the numerous mirrored bulbs (which pull higher amps), I hope most of the heat issue goes away. It already seems to be better after fixing the backbox GI.
 

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