Im having a troublesome issue with my Stargate.

The good:

Tournament mode works well, and the game is set on free play.

Mostly all LED lights.
New shooter lane switch, sarcophagus switch, outhole switch, trough switch.
A "light" spring was added to the trough gate to keep balls from bouncing back and triggering false ball counts.

New outhole coil and ball release coil.

New cabinet flipper switches.

Flippers completely rebuilt with complete kits from PBR.

Optos checked and cleaned

Drop target assemblies cleaned and inspected.

Kicker targets cleaned and rebuilt.

All connectors in the game have been reseated, all chips reseated, V4 game ROM and V3 DISPROM installed.

ColorDMD installed with German repro "clear" speaker panel plastic.

Sound is crisp and minimal hum from the cab speaker.

The game plays fast and powerfully and is a "joy" to play!

All switch test and lamp tests are perfect.

The bad:

Problem #1:

During extended gameplay, during multiball, the game loses track of the ball count.

The multiball modes end early, with as many as 3 balls still in play.

The flippers die and the balls drain out.

The it sets up ready for the next ball.

This doesnt happen in all games, and it happens on random mutliballs, sometimes twice in the same game.

It is mostly apparent in a Ra's bracelet mode when all 4 balls are in play, drain one ball and the mode ends draining the other 3.

Again its random and can happen in the glidercraft multiball but only have 2 balls during the mode but when 1 drains the flippers die and the mode ends.

This never happens in a short game, but always happens in a long "great" game.

This happens with the original trough switch as well as the new one recently installed.

It does not seem to be a TILT or a SLAM as there is no indication on the screen.

Problem #2 (could be related to problem #1)

If I take out all 4 balls and replace them "one by one", the outhole solenoid hesitates for up to 3 seconds to fire on the first ball but seems fairly instant on the last 3.

The outhole coil is plenty strong (and its the correct coil and resistance is perfect on it). but it isnt strong enough to clear 2 balls in the lower side of the trough.

It seems that the outhole kicker might also die when the flippers die?

This is somewhat of a problem as, when the mode ends early and flippers die, sometimes 2 balls can get trapped in the lower part of the trough and then the game is unplayable until I remove the glass and manually help one of the balls over the top to the higher side.

Wall voltage is a fairly continuous 117v to 121v.

I havent done any "ground" mods.

I have gad the game for a few months and this behavior is recent.

Any insight to this would be helpful

Not helpful.

Thanks for the bump!

New developments:

I left the game off overnight in my unheated but insulated shop.

Temperature was 60 degrees.

Turned on the game, waited 5 mins to warm it up.

I played 2 pefect games with no issues.

I left it sit powered up for 2 hours and allowed the room to warm up a bit.

Played one game and had 1 issue of a multiball ending early.

Waited 2 more hours,, played 2 games and each had at leat one mutiball failure.

Waited 2 more hours, all multiballs had failures and the game was unplayable.

Sound like a temperature sensitive issue,

Ill do the ground mods on monday and report back.

Meanwhile I ordered a new sytsem 3 MPU board from Barakandl/Weebly off of Ebay.

There are 2 available, one from Boston Pinball and the one from Barakandl/Weebly.

Im sure that they are both good products but the Barakandl one was $50 cheaper.

It will be here next week to try out.

Ill be doing the extreme ground mod tomorrow (cutting off connectors and installing soldered ring connectors)

My optos test properly, but one never knows what happens under load.

Id be inclined to just replace all of them at this 30 year old point in time.

One thing I did (testerday) was inspect the auto launcher and get the ball to rest on "it" instead of the tip of the shooter rod.

It was easy to replace the barrel spring and add a shooter washer between the spring and shooter housing.

This pulled the tip of the shooter rod back enough so that it sits about half a millimeter behind the launcher arm.

I also squeezed and adjusted the launcher arms so that they were centered on the ball in the playfield gtoove.

The launcher now, always makes it up the ramp with very few roll-backs.

I was reading about how an old pyramid motor/gear box, draws more current than a new one.

Extra current draw is a bad thing in a matrixed system.

Old motors seem to draw more current if they are just "gummed" up and need cleaning.

No replacements are readily available and I doubt that the windings are shot, but who knows!

When I have it apart I will certainly silicone grease it and clean out the electrical motor with spray.

I was reading that the nylon outer caps on motors can be removed and totally clean out old "gunk" and basically re-new the motor.

We'll see if I actually do this instead of just buying a new one, down the road.

I did look at this!

Sadly, nothing was acting up.

Its possible that the grounds are interfering with the data returns to the MPU board?

Or, its also possible that the MPU board might be having trouble "seeing" fast switch actuations, due to faulty connections or impending component failure.

I would like to hear about this more.

I will have more info, good or bad, tomorrow.

I removed the little ground board.

I absolutely agree that having the ENTIRE game running thru two little foil traces seens crazy.

Thay said, my board is in PERFECT shape, no cracks/hacks or wear at any level.

Most I can say is that the grounding areas are very slightly oxidised.

I seriously DOUBT that there are any severe grounding problems on my game.

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Just to future-proof my game, I decided to go ahead and remove the connectors to the ground board and place them on the ground plane of the transformer.

I stripped them, twisted them together, soldered them together, crimped them onto the ring terminals and then soldered them to the ring terminals.

These ring terminals accept solder fairly readily with a drop of flux.

They are absolutely ROCK SOLID.
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After the ground mod I played a few games.

The game plays "more sprightly"!

Game one:

Short game with no malfunctions/

Game 2:

Longer game, no extended multiballs. no malfunctions.

Game 3:

Longer game a couple 2 ball multiballs, during glidercraft the game ended early after draining one of the 3 balls in play.

Flippers died, balls drained the game ended with 2 balls still in play.

So, as I expected, the ground mod did nothing really (except maybe playing a bit more brightly) and Im back to suspecting the MPU board.

Yes, nothing out of the ordinary,

My thought is that it may be some sort of logic issue?

Im hoping that replacing the MPU board will have a positive effect.

I dont game any spare Gottlieb parts, so Im not adverse to picking up a spare CPU and driver board,

The new boards have a "host" of features including NVRAM and no battery.

I really like the new power supply boards too.

Bump

Any Ideas are good Ideas at this point !

My new MPU board arrives today.

Ill install it friday and report back.

If this solves everything, I would be surprised!

It would just be too simple...

I have discounted current draw from the motor as being an issue due to the game losing the ball count when the electric motors are not running.

Solenoids on the pivot targets are something to be explored.

My game does not have extensive plays on it. A lot for sure, but its not beat down to rubble like some of my other project pins.

So, Im not thinking that the smart switches (or optos for that matter) are worn out yet.

They seem fast and accurate in tests.

While waiting for the new MPU board, I was looking at the strobe lines for the lamps and switches.

Its quite a system!

However its not too bad to check the switch and lamp rows and columns at the same time.

Strobe 2 seems to be the common strobe.

Certainly, I guess a bad diode on a lamp could cause false closures in a row or column.

But, If that were the case, I would think that I would see additional lamps lighting up in single lamp test.

The game has all comet sunlight 2 SMD frosted lamps and 5 SMD tower flashers as well as some 8 SMD tower flashers for the #67 lamps.

I dont see any LED ghosting in the system at all.

I was thinking that ghosting might affect the switch performance, but that hasnt been reported anywhere yet.

And, Im not seeing any at this time.

Im thinking a lot about power today.

Specifically the 5v and 12v systems.

Im also thinking about resistance and age in older architectures.

I imagine that pumping up the 5v via the trim pot might have beneficial results.

At the same time, Im working the problem from the bottom and the top at the same time.

My feeling is that if all switches are good, then there is a power/signal/return problem when the game is under load.

I will replace the 12v bridge rectifier and the 10k cap on friday as well as install the new MPU board, since I have the parts in stock.

Ive already replaced the other 2 rectifiers just because I had them (the old ones tested good).

My thoughts are that an anemic 5v, with low current flow would probably manifest itself as phantom switch closures and erratic performance.

I ordered a Boston Pinball 5v supply to add into the mix just for future proofing.

I will likely order a driver board next.

I really think that if replacements for 30 year old boards are available (and they actually work) one should get them.

My experience is that older electronics are not as stable as newer more robust parts.

Im not really a fan of "cute" authenticity, if the system works the same.

Here is a small note from pinrepair.com:

"One chip that is critical to the timing of the CPU board is at U11. This chip must be a 74HC123AN or the game will not boot (or will constantly reboot). U11 must be this exact HC variety (a 74LS123 will not work)."

"74HC123AN: used on the CPU board at U11. Note this chip *must* be this exact HC variety (the AN suffix is important too so it appears). It's a strange situation where if this chip is suspect, it can cause boot up problems (or issues when the game is warm.)"

I'm definitely having issues when the game warms up.

If swapping the MPU board solves the problem then this might be the suspected failure.

The game plays flawlessly when its cold.

I received my new MPU board.

I really like it, it boots up twice as fast, and now I can actually see the eprom version again on my colorDMD.

Oddly the first of the 2 startup beeps/squeals goes by so fast its just a slight pop.

The game processing is faster and cleaner, no more lag!

The new board has NVRAM, so no more battery!

I was going to mod my original board with a coin battery but this is way better, and again, future proofing...

Sadly this did not totally solve the lost ball issue Im having.

However, oddly, its very reduced and the game does not become unplayable after several hours of run time.

So, its a lot better! But not perfect yet.

Time to move on the the next item...

One of the recommended mods on Gottlieb system 3 is to do something about the terrible power supply board.

While trying to track down my switch issues, I started looking at the power.

Testing the output of the 5v power yielded not so surprising results.

Im getting 4.94 at the supply board and 4.25 at the MPU. Oddly the new MPU still funcions at this low voltage.

I expected a .5v drop from the cabling and connectors.

The little adjustment pot is VERY finicky and near IMPOSSIBLE to get right.

If I just tap it it goes way up or down but not where I want it.

Replacing the POT with a 10 turn or better, is probably an ok solution but I bought a new power supply board instead.

I bought the Boston Pinball power board as they removed the POT and put in DIP switches.

Its a great set up.

The new Power supply board is outputting 4.97v and reads 4.6v at the MPU.

I clicked the DIP switches one at a time (as recommended from Boston Pinball) and now have a ROCK SOLID 5.13 at the MPU board.

WOW, this really woke up the game YET AGAIN!

My game is betting faster and stonger every day.

Im going to have to make some mechanical adjustments.

Im now getting air-balls off the flippers.

Balls are hitting the glass, and flying onto the wire ramps, or all the way into the shooter lane!

Game play is fast and furious! Ramps are a breeze to make. Hitting the pyramid from the upper right flipper is fast and accurate!

My game is getting to be AMAZING!

But, still loses track of the ball count once in awhile. This is too frequently for me.

I read about checking fuse holders in the repair guides.

As I was checking the holders, I found an 8 amp fuse installed in the trough coil fuse holder.

THIS IS EXTREMELY BAD !

Finally it has dawned on me that this ball count and trough issue has been going on since before I bought the game.

Now it makes sense that the ball release and trough kicker coils were dragging and had to be replaced.

Something really BAD had happened in the past.

I replaced the 8 amp fuse with the 0.5 amp recommended one.

Powered up the game several times and the fuse is holding up perfectly.

Still however with all of the changes Ive made, the outhole kicker is sluggish to respond after the switch is actuated.

It can take up to 5 seconds for the kicker to respond after a ball lands on the switch.

I think something is amiss here....

Time to look at the driver board.

After seeing the 8 amp fuse incorrectly placed.

Im very concerned about serious damage the the driver board.

Sure enough, both the ball release and the trough kicker MOSFETS (q27 and q29) have been badly hacked and worked on.

I think Im finally getting very close to the ball count problem.

The board is a mess.

I found a damaged trace on the outhole kicker MOSFET.

I added the jumper wire (with a little "wire wrap" wire) as the trace under it was cut 3/4 the way across and scored deeply. Possibly from the original repair guy trying to salvage his terrible work, or the next guy checking for problems, as I am doing.

There is no "easy" fix for the blown VIA's and overheating of the fiberglass.

Adding the jumper really stabilized the game issues when the game is totally warned up.

But it still didnt fix the ball count issues completely.

After seeing the over-fusing and damaged coils and the bad MOSFET board work, I suspect that the chips at U3 and U4 are heat damaged or compromised in some way.

You can only barely see from my photo, but the top metal edge of MOFET 27 is scarred from countless ground firing tests.

Also notable is that Q27 looks like it has been replaced a couple times (possibly searching for the problem my game has?), due to the way its been soldered on top of the existing pins of the prior "hack".

I have no complaint about this method, it has saved a ton of boards from being ruined by inexperienced board repair technicians.

The replacement? MOSFETS are identical the existing ones. I'm confident that they are "pulls" from another board.

So, a bad hack job using sketchy unproven parts? Welcome to pin-repair, lol.

I have ordered and new driver board from Barakandl, it'll be here in a week.

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The delayed response from the outhole switch to the coil actually firing is troubling.

5 and sometimes 8 seconds, really? Lol. If a slingshot did this it would really be noticable, and terrible.

No other coil in the game has this problem.

Im crossing my fingers that the replacement driver board with solve this.

Im still waiting on the new driver board.

Meanwhile, Im continuing to molex mechs as I remove and inspect them.

Nothing is particularly worn out, or even that dirty for that matter.

However, it was fun to clean up the 3 drop target assemblies and add tiny bits of lubrication via the super lube pen.

Cleaning/lubing the kicking stand-up targets was particularly rewarding as now they are TWICE as powerful and fast!

Tiny amounts of lubrication on metal to metal friction areas with a dry lube or a non-drying lube like super-lube silicone oil is recommended by the manufacturer.

The key is tiny amounts, and wipe off all the excess. With these modern lubricants, the tiniest amount is all you need.

I will get back on this project after the holiday.

Thanks for listening to me rant, lol.

Yes, I have rivets and eyelets for this type of repair!

Thanks for the recommendation!

But, for the money and time, PLUS getting "improved" electronics that are NOT 30 years old, I bought a new board.

I lost confidence in my driver board, mostly due to over temp, over-fused ( 8 amp fuse for the trough coil) circuits from the prior experts who worked on this game (and having to replace both swollen coils in the trough).

I believe that these same experts drilled the hole in my coin door, to put in a credit switch.

It was very neatly done, but the loose wire that fell off the center kicking target, was drooped down and easy to spot.

This was the only problem that kept it out of tournament mode for free play.

Just like installing the replacement MPU board, I would be shocked if swapping the driver board totally solved the problems with this game.

The outhole "delayed response" problem is troubling...

Yes sol 28 and sol 27 were very damaged (The ball release coil, switch and plunger and spring have been replaced and are NEW). The ball release seems to work properly and quickly enough.

This is indeed mysterious!

The switch on the outhole is a regular DB5 or DB3 microswitch (I have bags of those) with a flatblade actuator, mounted on a plastic bracket (I have spares of those too).

The switch registers promptly and immediately in test, and no other switches activate.

(During the "playfield smack-down thunk" test, I did get a closure on the sarcophagus drop target. I adjusted that properly when I recently rebuilt the mech).

I replaced the outhole switch "twice" with new ones thinking that maybe I put in a bad switch (it happens lol). The ones I pulled out work perfectly.

The outhole coil was heat damaged, swollen, and dragging on the coil (evidence of a problem in the past).

I replaced the coil, spring, plunger and link. I removed (pulled one leg off) and tested the diode on the NEW coil, it tested good. Then I removed that diode and installed a new "tested" IN4007 diode, just to be sure.

I havent traced the wires from the coil and the switch yet for shorts or breakage, but moving the harness around hasnt made any changes.

The NEW driver board may arrive early today. Ill install it and report back.

The next step I can do is trace the wires from the switch and the coil to see if there is any mischief going on there.

All of the boards I bought were really just to future-proof the game, with needed upgrades (the MPU and power supply specifically).

Again, the OLD driver board can be repaired, but a new one isnt expensive and I feel better about newer parts.

So, Im happy with them.

I received the new Driver board.

It installed with no problems. Its a really great and clean board! Very robust and well made.

Im happy with the new non-hacked board.

Sadly this did nothing for my odd game behaviors, its still the same and unplayable.

Outhole coil is still sluggish to respond.

All multiballs end early, flippers die and sets up the next ball in the shooter lane.

Next to check are the optos.

Ill clean and reflow the solder on the little boards as well as check the connectors.

I do have a spare 4 opto board and a spare filter capacitor that Im going to install.

Ill report back with the result.

Going over the switch matrix.

Today Im swapping the right outside smart switch with the left one.

Given time, I will pull the wireforms and reflow the opto boards.

Right now Im rebuilding the left kicking target, and the bullseye targets since they are on or near the strobe lines for the trough switch.

The bullseye switches have capacitors on them that might be bad or missing, I will just put new ones on.

I will attempt to get through to PBR to get 5 new pairs of opto boards on my next order.

I still haven been able to get through by phone.

The optos dont seem to be a part of the trough circuit. But its been reported that extra balls can be added from a flaky opto on the ramps.

The game has 5 pairs of optos, but only 4 of them appear on the matrix chart. Also the subway opto doesnt appear on the chart.

I imagine that the subway one is just piggy-backed onto the left VUK opto since the opto board only supports 4 opto pairs.

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Going down the switch list from top to bottom, and side to side looking for common problen causes.

Examining the left kicking target.

I found a loose wire hanging by a thread!

Its attached, but unlikely it carries much current or signal.

Its on a return line, not a strobe.

But its important nonetheless!
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I fixed it by adding a molex and crimping the 2 wires together onto the same pin instead of the brittle solder joint.
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This wire often falls off.

Its connected to the tourament switch.

This repair should help solve that problem in the future maybe.

Since I molexed the bullseye switch and the left kicking switch (and its solenoid), I can now easily remove them for cleaning and maintenance.

Both are pretty crusty.

I always molex everything I pull off of a pinball machine these days.

Its just a better approach to the work in general.

I got my marco order.

I replaced all 4 sets of optos and the 4 opto controller board.

The subway opto (pyramid top) is a smaller opto than the rest. I didnt order the pair but they work perfectly.

During this opto replacement job I found MANY marginal solder connections.

I also took the time to rebuild all 3 VUK's.

All 3 were missing springs and needed coil sleeves and new coil stop brackets.

They are all NEW now and work perfectly!

The new optos are much faster responding than the old ones. This was a great upgrade!

Still however the game is unplayable.

Multiballs end early, flippers die and a new ball is served until the game ends.

Today fuse F21 blew and the right kicking target coil is locked on.

I pulled out the coil, checked the diode and tested the resistance of the coil (A-5195).

The diode tested perfectly but I replaced it with a new IN4007.

The coil resistance is 15 ohms. It should be 11.5 without the diode.

Its not too bad and pretty close to spec, but Ill replace it anyway.

I orderd a couple new coils from Marco.

My new driver board evidently blew a mosfet! Theres nothing wrong in the circuit.

I put my old driver board in and the coil is not locked on.

So, I orderd some IRL540 mosfets from Marco.

Ill repair the "new" board in a few days.

I read that also, so I disconnected both of the motors and played a few games but the problem persists.

Im having positive results by making extreme adjustments to the trough switch.

One thing I noticed is that the "new" trough switch's spring tension is much "lighter" than the original switch.

Its extremely sensitive. It can be triggered by "thunking" the playfield.

Since I have gone thru the entire game now, and fixed dozens of problems that I wasnt aware of, the game plays FAST and powerful !

De-bouncing the trough switch seems to be the last item to solve.

I put the old trough switch back in yesterday and had positive results.

The game played perfectly until the Ra's temple mode.

This is a 4 ball multiball.

With the ball trough fully emptied.

The mode ended early with 1 ball still in play, flippers died, ball drained, next ball set up in the shooter lane.

Im going to rig up a detent for the trough switch to de-bounce it a little and see if it has a positive result.

Oddly, for the moment, only the Ra's temple mode is ending early.

The final 7 segment mode did not end early.

Im running version 4 of the game ROM right now.

Yesterday I replaced the Right Outlane "Smart Switch" as it was last on the switch column that includes the trough switch.

It did not solve the problem.

So, as of now, all related switches (plus a lot more) have been replaced. As well as several "out of spec" coils.

Yestereday the backbox "Rope Light" stopped working.

It was a simple fix.

The top side of the far right resister on the light insert panel was loose and had become unsoldered from the heat.

It was very oxidized. Some cleaning with a fiberglass brush, flux and resoldering, fixed it quickly.