Solenoid Driver Board Problems

[gajaman]

I recently bought my first pin - a Bally Space Invaders.

I have problem with some of the coils firing at the wrong times or not at all that has stumped me.

The problem affects the single drop target and two of the three thumper bumpers. The drop target and one of the thumper bumpers wont work at all and the other thumper bumper fires the wrong coil. I have confirmed this in the coil test mode.

I have tested the wiring by grounding the transistors and this makes all the coils fire correctly indicating the wiring is good. I have also tested the transistors themselves with my DMM and have similar readings on all of them.

At this point I didn't know what to do next. I saw a replacement board on ebay and bought it as it was cheap and apparently 100% working.

This arrived yesterday and after checking I had 5v at TP1 I hooked it up with high hopes.

This board blows the 1amp fuse under the playfield as soon as the pin is plugged into the mains.

So, now I have one board that works fine except for 3 coils and one that blows the playfield fuse.

Any advice on where to go with either board next?

[StephenH]

Here is some info for your pinball system:

http://www.pinrepair.com/bally/index1.htm#top

[gajaman]

Thanks for the reply StephenH.

I've used the pinrepair guides a lot since I got the machine but having the read the whole section on solenoid driver boards I just can't find anything that would cover the under playfield fuse blowing as a direct result of the solenoid driver board. I know it's the board as the fuse doesn't blow when I plug in the other board which doesn't fire all of the solenoids correctly.

Help!

[gajaman]

Thanks for the reply.

All of the coils have 43v at all lugs. The J5 connector looks ok and when I short each capacitor the correct coils fire making me think that the connector is ok?

Which leg should I cut (there are three) and what will this do?

The game does not have an expander board.

[gajaman]

Thank for the help.

I snipped one leg of the capacitor next to the transistor that controls the single drop target on the solenoid driver board;



(The orange disk)

Unfortunately, this hasn't made any difference.

I don't think the problem is the MPU as this is a new ultimate replacement.

When you say "look at the schematics to see what's associated with the logic to handle those coils" can you elaborate at all? I've learned a lot so far about electronics but I'll need a bit more direction I'm afraid.

Thanks 

[smartbomb2084]

I'm not real familiar with this Ultimate MPU garbage, yes garbage, but don't you select the game it is to be used in with DIP switches?  Do you have the right ones set?

[gajaman]

Smartbomb2084 -  I thought the dip switches could be wrong so I used the memory clear feature and then reset them to the correct settings. Made no difference.

pinballjim - I didn't think it was right, now resoldered. I clipped the capacitor on the switch on the drop target;



Didn't make any difference I'm afraid.

I'll go through the manual and diagrams tonight to see if I can work out if the non-firing coils are grouped together as you suggest. If it's not obvious I may need to come back for more guidance.

Thanks for the help.

[smartbomb2084]

Sorry my friend but that last picture you posted shows that you have clipped a DIODE and you need to reconnect it immediately because the switch matrix requires it and you will just have even more headaches.  Not all the Bally switches have capacitors on them.  It usually is the pop bumpers and kickers that have them.  The reason they are there is that Bally was worried that the MPU would be too slow to react to the switch closing or maybe even miss it all toghether. The capacitor lengthens the time the MPU has to 'see' the switch. Remember the capacitors are disc shaped like the one you cut previously on the Soplenoid/Driver board.  Did you test the swiches by hand in the switch test mode like you did the coils?  Did you check all of the transistors on the Solenoid/Driver board that blows the playfield fuse like you checked the transistors on the original board?  Did you check the switch wiring?  Have you disconnected the TILT?

[gajaman]

Hi smartbomb2084

I did think it was a diode but thought maybe capacitors came in that shape as well doh! I'll re-solder it.

It appears that the drop target switch does not have a capacitor then.

I have tested the switch by placing it down in test mode. It comes up as stuck until I manually move the target up by hand at which point it passes the test.

I haven't checked the transistors on the second board and will do this.

The switch wiring I think is fine as the target resets if I short the transistor on the SDB.

The tilt is not disconnected, not sure why this would make a difference as it works fine on the board that doesn't blow the playfield fuse?


Thanks for the help.

[gajaman]

So, I've checked the transistors on the second board and have come up with two odd readings.

The first is on an outside leg of a transistor that is not used by the game, all the transistors outer legs read in the 400 - 600 range on the outside legs except this one.

The second is on a centre leg of a transistor that is used by the game, all the transistors middle legs read as 1 on my DMM except this one that reads 2.

Will the transistor not used by the game be causing the problem? Could I swap a good one that is not used by the game for a bad one used by the game or do I need to replace any bad one used or not?

[smartbomb2084]

I would like to see you put a new transistor in BOTH places if possible.  I hope you have some de-soldering skills so you don't damage the board because removing them is the hard part. If you have a good solder sucker and have the skills then go ahead and rob one board temporarily to fix the other.  The call is entirely up to you.   As far as the TILT goes it has been known to cause switch problems in the past.  Start a game and put one hand on the metal siderail that holds the glass and put your other hand on one half of the tilt at the same time.  Repeat the process with the other half of the tilt.  Anything weird happen like a popbumper or other solenoid firing on its own?

One more thing, shorting the transistor does not prove that the SWITCH wiring is good it only  proves the transistor is connected to the coil.  By doing this you are bypassing all of the switch wiring and all of the logic of the MPU.

[gajaman]

I've ordered some new transistors and will swap them out on the second SDB board. My soldering skills are ok but if I do screw up I will still have the other board I guess!

I've order TIP102 transistors as I couldn't find ones coded TIP102c in the UK. Will these be ok?

I've ordered these ones;

http://www.pinballheaven.co.uk/shop/product_info.php?products_id=101

I'll try the tilt test later - thanks.

Cheers for putting me right on the switch. How do I test the switch wiring with my DMM?

Thanks for the continued help!

[smartbomb2084]

The TIP 102 will be fine to use .  Usually there are SE 9302 transistors in the board.  It is better to change them to TIP 102's anyway when they need replaced as it is a heartier transistor.   Does it look like they have already been changed  previously by someone else?  You can often tell if that is the case because the solder will be a lot shinier than the factory solder and there is usually traces of flux that isn't on a factory connection.

 The best way to test switches is in the games' switch test mode.  Other than that you can use your DMM to test for continuity between like colored wires in the switch matrix with the power off of course.  Look at the switch matrix in the manual and find your problem switches.  Each row and column is one wire with each half of a switch connected to it in a daisy chain fashion.  If a wire breaks somewhere often more than one switch is affected unless it happens to be the last one in the row or column.

[gajaman]

The transisitors all look original. I swapped the two out with the new ones and made a really tidy job even if I do say so myself! I bought a desoldering pump which is excellent.

This has however made no difference with the playfield fuse still blowing the minute I plug in the machine with the repaired SDB connected.

I tested the switch using the test mode and it shows as locked on when the drop traget is down but not when I manually reset it. All other switches show as having no fault during the test.

Any other ideas?

[smartbomb2084]

On the board that is blowing the playfield fuse, try removing the flipper relay as it may be shorted.  There really isn't a whole lot of +43 volts on the SDB when the transistors aren't switching the coils to ground.  The flipper relay has +43 volts going to it though.  Since the playfield fuse only blows with one particular board installed the +43V must be grounded by the board somehow. You can also see if J3-pin 9 is grounded as this is the flipper relay +43V supply.

On the other board that doesn't blow the fuse, you say that the wrong coil fires even in test?  If this is true then the BCD data may be getting corrupted by an intermittent  J4 connector. Unsolder and resolder all the pins on connector J4 and while you are at it do that to all the connectors on both SDB boards and let's go from there.   

[Karetaker]

Did you check your switches for adjustment. With the board that is firing coils when it shouldn't hooked up take your fist and bang on the playfield in game play. Not real hard but hard enough to get some vibration going. If any coils are firing when you do this you more than likely have a switch adjusted to close. Cleaning the switches might not be a bad idea either.

[smartbomb2084]

Check  out my old Gaja Project that I use for MAME.

[gajaman]

smartbomb2084 - I've unsoldered and resoldered any joints on the connectors that looked iffy and this hasn't made any difference I'm afraid.

On the board that blows the fuse the flippers still work after the fuse has blown. I guess this means the flipper relay is ok?

Karetaker - I whacked the playfield as hard as I dare and nothing fired. I've cleaned and adjusted most of the switches and this also made no difference but was good housekeeping I'm sure.

smartbomb2084 - Nice controller! Defender is my all time favorite game. I've been away from the mame scene for quite a while (other than playing obviously) but recently dipped my feet back in with this:





I really wanted to try and build something small that did not look like a traditional arcade machine and this was a small as I could go with stuff I had laying around. I've got a plan to build a full sized Defender replica but chopping most of the back of the cabinet off using a flat screen so i can fit it in my house without my wife killing me!

Any further help with the SDB gratefully received. I guess I could buy a new replacement SDB but I feel like that would be admitting defeat.

[Karetaker]

Wow, you really do have a problem...LOL! Is it only when you are playing a game that the coils fire when they are not supposed to? If you fire up a game and just let the ball sit in the shooter lane do they fire, or only when you are playing a game with the ball in play? I'm not sure if you are chasing one problem or a few problems here. Try CARFULLY pulling the game Rom and cleaning the pins. Coils not firing could be a connection to one of the boards, since they fire sometimes. Could be a solder joint as well. Also check the diodes on the flipper coils. Put a small screwdriver under them and twist a little to make sure the leads don't come out. That's a long shot as when that happens a pin will normall lock up or do other weird things. But, a bad diode on a flipper coil can make a pin do some strange things.

[smartbomb2084]

Nice cabinet.  It is all self-contained complete with monitor, mother board, and power supply?  Is it running MAME?  My old controller is just I PAC powered to play DEFENDER , also my favorite game, and STARGATE.  I kept it old school though and used leaf switches and a reproduction UP/DOWN stick.  I never use it anymore as I have a ROBOTRON cabinet with three boardsets in it to play ROBOTRON, DEFENDER, and STARGATE.  I have a rebuilt ROBOTRON control panel and a rebuilt STARGATE control panel to play DEFENDER too as the two control panel dimensions are the same and they just bolt right up to the cabinet.  I made custom wire harnesses out of old shuffle bowler molex connectors for each boardset (Male) and for the cabinet (Female) and seperate ones for each control panel. To play a game I just plug in the appropriate wire harness right through the coin door.  It is nice to have the original hardware and boardsets to play on as it is quite a bit different than using MAME.  Somthing to think about when you make you DEFENDER cabinet.

As for your SDB problems. I will have to look at the drawings some more and get back to you.  I really wish you would have soldered ALL the connector pins even if they look good to the naked eye. Anytime you can eliminate some doubt it is a good idea to do so.  J4 on the board that doesn't blow the fuse should definitely be resoldered regardless of how it looks as this is the BCD data that selects which solenoid gets activated.  I still haven't ruled out the fliipper relay yet.  One way to find out if the flipper relay is shorted is to see if the flippers work on the fuse blowing SDB in 'GAME OVER' mode.  The relay keeps the flippers inoperative until a game is started and the relay is activated by the MPU supplying a ground path to the flippers.

Have any of the connector plugs on any of the wiring been replaced already?  Does the game have plugs with crimped on wire ends or does it have the red AMP style IDC plugs?  IDC= Insulation Displacement Connector

[gajaman]

Karetaker - the coils only fire during gameplay and always at the same time (ie when the left thumper bumper is hit the right slingshot fires. The right thumper bumper and the single drop target just don't fire at all. I don't think the game rom is a problem as the MPU is a new replacement Ultimate board.

smartbomb2084 - The cabinet is completely self contained with a single power lead from it. It runs mame with Party On as the front end. It has an i-pac inside as the interface. Like the sound of your Robotron with mulitple boards - great solution for a Defender fan.

Thanks for the tip about using original boards for my Defender project. They rarely come up in the UK and are very expensive when they do. Also I'd have to abandon my flat screen idea which would make the cabinet full size and not thinned down undoubtly removing all goodwill from my wife about the project! That could be a deal-breaker.

I'll desolder and resolder the J4 completely. I think the flippers stopped in game over mode on the fuse blow board. I'll check this out later to be sure.

I'm not sure about the connector plugs, are you referring to the connectors to the boards or connectors in the wiring?

[smartbomb2084]

I am talking about the plugs that carry the wires to the pins (jacks) on the boards.  I am not real sure where to go next.  Sometimes it is a bit hard to diagnose certain problems without being able to see the game in person.  The playfield fuse only has the playfield coils connected to it on one side and the flippers on the other. If the fuse is blowing it almost has to be one of the coils or a bad transistor.  Have you checked the diodes that connect to the transistors on the board?  Have you checked the pre-driver ICs U1, U3, and U4?  On the SDB that blows the fuse does it power the displays properly?

[gajaman]

I desoldered and removed the J4 connector cleaned it up and then resoldered it. Same result I'm afraid.

The plugs are white plastic with wires that appear to be crimped in the holes but I can't see how they are crimped.
I haven't checked the diodes on the fuse blowing board or the ICs U1,U3 or U4. Presumably I can check the diodes with my DMM? Do I need a logic probe to check the ICs or can I do this with my DMM.

I'll have to check the displays on the fuse blowing board. I can't remember if they work, I think not but I'll need to check.

Thanks for continuing to stick with this!

 

[shardian]

This really sounds like a wiring/switch matrix issue. The thumpers and the drop target are all tied to the same pin on the J2 connector. However, the slingshots and upper flippers are also on that pin. Any problems with those? Maybe you have a bad diode somewhere causing a jump in the matrix? You can bypass the diode on the problem switches to see if the switch registers correctly then.