View Full Version : Schematics Misleading and otherwise!!!!

16th October 2012, 09:08 PM
Hi All,

I thought it was about time I made some contribution to this great forum (after taking so much from the various threads others post).

Apologies in advance, if the pictures attached are oversized - I am not across how to reduce the size of the picture!!

This weekend I embarked on bring a Bally Fireball Classic back to life - in readiness for a meet in December:cool:.


By way of background, I had the wiring in my garage (Mancave) upgraded to include a trip swtich which detected any applicance not properly grounded or shorted. Turning my Fireball Classic on tripped the switch each time.

After spending an entire Saturday I discovered the wiring of the motor appears to be incorrect. Referring to the manual and schematics (downloaded from IPDB *), the way they wired up the motor appears to be pretty slap-dash!! Both the active and neutral wires come attach to the AC side (after the transformer itself and before the bridge rectifiers) by linking onto the default transformer wiring???It would appear they have simply taken standard power supply modules of that vintage and connected the motor in the most amateur way possible.

44310 4431144312

At first I thought this was an after market hack, but in fact it is factory!!!! 44306. Again apologies if the JPEGs are illegible, you can view them at IPDB.org.

I raise this because, the manuals and schematics should be considered the Bible when repairing Pinballs (and they will always require TLC). Here, directed by the schematics, I was working with AC, and what appeared to be after thought wiring, giving no specific direction as to which wires should be linked (from the schematics), coming straight from the transfomer. All to get the main feature of this game working (the game is crap without the disc spinning).

At this point I should declare, I am completely self taught and use simple logic (and now the internet) to solve pinball problems. Granted I have had too much experience in the 'trial and error' method of gaining knowledge, but it strikes me that the manufacturers should have provided schematics that the lowest common dominator (Dummies like me and maybe the less experienced) could understand.

Unless I have missed it, Fireball Classic is a 'Classic' example of the manufacturers dropping the ball. I hear my Contempories saying this is a sign of those times? The mid eighties might be considered a low point for Pinball. Cost cutting might have being the order of the day, but that should not excuse providing sub-standard schematics.

And it gets worse. AND this is probably my main point.

Once I solved the motor problem, attention turned to the logic lights. On this game the bonus increases on a 5K increment (ie 5K, 10K, 15K, 20k, etc)

Looking at the Schematics they refer to 2K, 4K 6K etc, bonus lites!!!

The Manual was silent - note Bally Operator Manuals usually provide a diagram of the playfield showing where each logic light is and its description. This is all a bit confusing?:confused:

It is challenging enough to get these old girls working without having to deal with a wild goose chase.

Which is a long way round of posing this question.

Maybe we should have a thread to outline the errors (forgivable and otherwise) in the paperwork that should assist in troubleshooting. If someone had discovered this issue prior to me stumbling across it, I would have saved a lot of time, energy and hair - all of which I have precise little of of!!

I look forward to hearing from other Fireball Classic owners to see if they have the same problem. AND others that might have stumbled across the odd error in the paperwork that goes with their machine......

* I did buy a paper version of the manual and schematics and have yet to confirm they are different from those now available online, I would find it difficult to believe they would be contrary to the ones published on IPDB.

16th October 2012, 09:38 PM
Hi Again,

By way of a second example where the paper work has some deficiencies. Please see the switch matrix for 1980 Williams Black Knight (my favourite game of all time and possibly the reason for my 'decay' into this hobby:().


Unless I have missed it, I cannot see where the Left Kicker is??? Naturally referring to the other diagrams in the manual you can deduce (by process of elimination) the Left Kicker is actually switch No. 21. The switch matrix clearly states Switch No. 21 is Lower Kicker 3-Bank, Left Target.

This might be considered forgivable. However looking closely at the matrix ? could there be some secret to be unearthed in switch No. 28? Could this be something useable like the drop target version of Firepower??? I cannot recall stand up targets in this game yet Switch 28, 32 & 40 are labelled stand up targets? Note the remainder of the switches in the matrix state they are simply ?not used?.

17th October 2012, 04:38 AM
Great write up - keep it coming.

You would be AMAZED at the errors I find in schematic diagrams from ALL manufacturers. Incorrect traces, wrong part values and parts connected (according to the diagram) in such a way that it would be impossible for the circuit to work!

This makes it tricky sometimes to lay out a new board without having a machine around to actually test the first prototype in....I use the schematics as a guide only and I am always on full alert if I am re-creating a board without having an original board in front of me to confirm things.

17th October 2012, 07:26 AM
keep in mind the schematics generated are the "design" stage, and may also have been copied from pervious games of similar type.

the "production" stage may have identified some errors and reported them but the updates may not have made it into the design schematics.

"configuration management" is something auto and aerospace manufacturers would have been good at in the time, doesnt mean consumer goods manufacturers were good at it.

imho williams is a good example of a co that was pretty good at it in the time, but getting revisions and updates and service bulletins out to the industry really depended on the people at the time in those roles

i'll stop wafflin now.

17th October 2012, 08:53 AM
keep in mind the schematics generated are the "design" stage, and may also have been copied from pervious games of similar type.

the "production" stage may have identified some errors and reported them but the updates may not have made it into the design schematics.

"configuration management" is something auto and aerospace manufacturers would have been good at in the time, doesnt mean consumer goods manufacturers were good at it.

I've encountered this repairing a Philips TV for g/f (at the time).
The schematic was supplied in the back of the TV. The horizontal IC had blown.
After replacing it all voltages checked OK but blew again a few weeks later.
Checked again,all peripheral voltages were OK.
Sent it out for repair. Diagnosis was that, apart from the IC, a zener diode of a different value had to be replaced.
A fault from manufacture, but being a layman, had no idea with no access to update bulletins for the original schematic.

29th October 2012, 01:10 PM
I found another one!!!! :huh::huh:
checking the logic lights this weekend and found another mistake in the schematics.

Again forgivable, but that makes 3 out 4 machines that have basic errors in the paper work - FBC, BK and now EBD (firepower appears ok - so far;)).

on J3 of the light driver board the schematics refer to two different 4X Bonus lights (only one on the game). turns out the second one should really be 5X Bonus!!!!

Pin out 14 is 5X Bonus.
pin out 24 is 4X Bonus.

Not the end of the world, but added time un-necessary.:(:( to the repair. I could have been playing it instead of tracing wires all over the shop<_<<_<

15th November 2012, 10:03 AM
You've brought to light one of the headaches of any technical organisation - documentation.
Documentation costs money like any other part of the manufacturing process and as expected , manufacturers will spend as little money as possible to get something done. Considering the number of components,wires,switches,etc. in just one pinball machine , pinball manufacturers have probably done pretty good over the years in the documentation area.
As a long time tech. , I always consider the documentation as a guide only until proven in the real world. Knowledge and experience keeps me "on guard" for unusual and weird things.

27th January 2015, 09:04 PM
It has been some time since I posted this thread.
Alas I must return to it as I have found another paperwork error.

In preparing to Host for the 2015 opening round of Sydney's Wildball. I have been fine tuning my Bally Spectrum. A sleeper from April 1981.

The game is based on a board game from the 1970's. Mastermind. Where you must determine your opponents colour code via a series of guesses - read knocking down the drop targets which are colour coded. Just Google the game and you will find a many references to this game.

It is a classic example of the SS era, when Pinball was moving from the simple mechanical logic of EM's to a computer based logic providing more variables for both the pinball designer and the player.

I think the game was not well received because it was to complicated for the playing population at that time. It has a great strategy that many would say was before its time. it also makes for a good game to practise on.

Anyway, attached is the offending page (4) from the manual (which was retrieved from ipdb.org).


At point E on the page, the manual states -'if the light is flashing this means an incorrect guess.

In fact it is the exact opposite. if you do manage to select the correct colour it will flash. If your selection is incorrect the light will remain on solid.

You might say is it a minor error, however, it directs the reader in the exact opposite direction. Did the people at the manufacturer actually read through the paperwork prior to its public release. What was the process of review?

Looking back I reckon this simple mistake added to the confusion that surrounds this game even to today....

In trying to explain the game, I have failed on many occasions to get my point across (you need to know how to play the board game Mastermind to really understand how to play this machine). So you're off to an awful start by referring to the manual to get up to speed on how to play this game!!!

I do not want to be too critical as I provide written documents to clients each and every day. through standardisation and procedural review we manage to ensure error of this nature are avoided.

With the luxury of hindsight, looking back I wonder if they were just going through the motions??

27th January 2015, 10:02 PM
Great game. Played on VP regularly a few years back.
I will pull it up for a game to check that as soon as all my nasty viruses are gone.

Sent from iPhone using Tapatalk

28th January 2015, 07:01 AM
I fully understand your frustration on the topic.

28th January 2015, 07:33 AM
Yes its a headache. Reverse engineering a schematic from a pcb is harder. Defining whether a unit is economically viable to repair for a customer prior to embarking can be harder still. That's partly why I have a minimum charge/ inspection fee. No wonder electronic techs are a dying breed....

28th January 2015, 11:08 PM
the manual states -'if the light is flashing this means an incorrect guess.

In fact it is the exact opposite. if you do manage to select the correct colour it will flash. If your selection is incorrect the light will remain on solid.


I like how you can get the clues to eliminate the wrong guess. Simple game really.

29th June 2015, 06:03 AM
It is with a tinge of sadness that I post this, the latest instalment to this thread :cry
Here we look at a short coming in the Schematics of Ballys Centaur, a Classic from 1981. A favourite of mine and a game sort after by players and collectors alike.

The addition of this game to this thread now means that most of my favourite machines have misleading paperwork (errors) :(:(
Special thanks to JPD, who discovered the issue. I found the same problem in my Centaur! and would welcome other Centaur owners observations.

Although I am not sure he hadn't been involved with the game from inception!! ;) Who approved (that's what I assume AP'D means!!) the schematics?????
Whilst we are here, please read the disclaimer and ownership statement -
http://i1358.photobucket.com/albums/q766/68Pinball/20150628_1825411_zpsddsfwwe3.jpg (http://s1358.photobucket.com/user/68Pinball/media/20150628_1825411_zpsddsfwwe3.jpg.html)

The background, Lane change was the latest thing back in 1981. Williams Firepower (1980) led the way, Centaur was one of the first Bally games to have this feature. The top lanes have lights that can be moved by pressing the flipper button. Seems rather secondary now, but it was quite a cool feature back in the day. it is pivotal to game play on Centaur!

One of these lights was having issues so when we traced the wires back to the Light Driver Board (an Auxiliary board) we made the discovery. Here is the point of this thread.
This 'discovery' took way longer than it needed to!!! In what should have been a quick fix (I use the phase liberally), we spent our value beer drinking and playing time scratching heads and looking aimlessly into the backbox again & again & again.
If your not careful these little errors, flaws, transgressions, glitches, etc can make the most experienced look like an absolute rank amateur.

The technical.
In short the left and right lights have been switched around.

The schematic shows the left lane light at pin 7 (A9J2-7) of the Aux Light Driver Board to have white with green trace (colour code 54). The right lane light at pin 18 (A9J2-18) is coloured blue with white trace (code 25).
http://i1358.photobucket.com/albums/q766/68Pinball/20150628_1825231_zpsbnfnucvq.jpg (http://s1358.photobucket.com/user/68Pinball/media/20150628_1825231_zpsbnfnucvq.jpg.html)
apologies for the lack of focus.

Before looking at the light sockets, we need to look at the connector between the backbox and the playfield. Here the colour of the right light wire (blue with white trace) changes from blue with a white trace to a lightler blue with a white trace. the light blue has turned gray with age (who hasn't <_<)
http://i1358.photobucket.com/albums/q766/68Pinball/20150626_2039221_zpsgx45chib.jpg (http://s1358.photobucket.com/user/68Pinball/media/20150626_2039221_zpsgx45chib.jpg.html)

Looking at the underside of the playfield. We can see the wires now appear in the opposite position. The gray (formerly blue with white trace) wire is now on the left light. The white with green trace (the green trace is not that obvious from the camera angle - it is there) is on the right side!!!!!:confused:
http://i1358.photobucket.com/albums/q766/68Pinball/20150626_2014411_zps7cyadpyx.jpg (http://s1358.photobucket.com/user/68Pinball/media/20150626_2014411_zps7cyadpyx.jpg.html)

With the wires in this orientation the game works as it should, ie, actuating the left lane switch lights the correct (left) light.

The trouble occurred because (I surmise) a prior owner, in trying to correct another unrelated problem, took the schematics as gospel, and soldered the wires as per the paperwork. Another sad example of the schematics leading a repair a long way from the solution. How would the most experienced Techs solve this?

Imagine confronting this problem in the wild for a customer! As stated above, it is pivotal to game play on this game. I would fully understand an owners frustration if this feature was not 100% functional.

The only way we found the fault was to check another Centaur! Not a luxury all Techs have!

I do not want to appear overly sensitive to these errors but,

If schematics are designed to reduce the amount of time attending to these issues. Emphasis should be placed in getting them right! As we have discovered, incorrect schematics more than double the amount of time consumed to solve these issues. A precious resource especially if your paying for it

For the super techs, please note the solder splash atop the left light socket is, purely aftermarket I am sure (amazing with you miss when you look hard enough!!)