Stern S.A.M. System Repair
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1 Introduction
The first full production game to use the S.A.M. Board Set was World Poker Tour in 2006. The last production game was The Walking Dead (Limited Edition) in 2014. One of the features of the S.A.M. board set is that the software can be updated with a USB stick.
S.A.M., as an abbreviation, has never been officially explained—but Sam Stern was Gary Stern's father, and formerly ran Williams and Stern Electronics.
2 Games
- World Poker Tour
- Simpsons kooky Carnival (redemption game)
- Pirates of the Caribbean
- Family Guy
- Spider Man (Stern)
- Wheel of Fortune
- Shrek
- Indiana Jones 4
- Batman (Stern)
- CSI: Crime Scene Investigation
- 24
- NBA
- Big Buck Hunter Pro
- Iron Man
- Avatar
- The Rolling Stones (Stern)
- Tron
- Transformers
- AC/DC
- X-Men
- Avengers
- Metallica
- Star Trek (Stern)
- Mustang (Stern)
- The Walking Dead
3 Technical Info
3.1 The S.A.M. Board Set
The S.A.M. System board set consists of three boards in the back box. The CPU / Sound board, I/O Power Driver board, and the Display Power supply. Later SAM games, which use LED dot matrix displays (versus high voltage plasma displays) do not employ the display power supply. Later SAM games which use LEDs in place of incandescent bulbs for all playfield lighting, add an additional board to power the LEDs, and on LE games, a board to control these LEDs.
The basic S.A.M. board set is a miniaturized version of the Whitestar board architecture. The board set is dimensionally reduced and manufactured with some surface mount components. The logic functionality is easily traceable back to the Whitestar board set.
3.1.1 SAM CPU / Sound Board
- The various generations of the Stern SAM CPU board
Stern first generation CPU/Sound Board 520-5246-00 Revision G. Note Jumpers which were incorporated into the PCB with Revision H 
Stern first generation CPU/Sound Board 520-5246-00 Revision G, back side. Note the jumper 
Stern first generation CPU/Sound Board 520-5246-00 Revision H (up to Tron).
The adaptor is not part of the CPU. It's used in the White Star test fixture.
Stern first generation CPU/Sound Board 520-5303-03 Revision H. This board is identical to 520-5246-00 but factory programmed differently to run the Limited Edition Code (here Tron LE). 
Stern second generation SAM CPU/Sound Board 520-5246-02 (Transformers and forward). The USB controller chip on this board changed to an FTDI VNC2-48L1B - Vinculum-II Programmable USB 2.0 Host. This is the AC/DC version of the board with 2 64 MBit flash roms 520-5337-01 (Pro) 520-5337-00 (Premium/LE). 
Another Stern second generation SAM CPU/Sound Board 520-5352-00 (Star Trek Pro) 520-5352-01 (Star Trek Premium). To make life for operators, repairmen and collectors easier Stern released another version of this CPU with Star Trek Pro/LE. It is identical to 520-5337-00/-01 but only has one 64 MB flashrom.
Up until now there are five versions of the SAM CPU/Sound board. The first version had several minor revisions over its lifetime, but they can all be used in all games up to Tron. The first revision of this board used in World Poker Tour has some problems with USB 2.0 sticks. If you own this game, see that you can find an old 32MB stick. They usually work fine. Second one has some hardware modifications in the circuit for the Atmel AT43USB380 chip. Starting with Transformers the USB controller became unavailable and was replaced with a different chip on the CPU. Number changed to 520-5246-02 and that makes three. All these boards use a 32 MB flash rom. With AC/DC space was running out and two 64 MB flash roms are used. To save a few bucks, Star Trek Pro and LE are fitted with only one 64 MB flash rom adding another variant to the pot.
The LE and Premium models use a variation of the Pro board. The programmed chips on them are different and so they are not interchangeable. Trying to use Premium software on the Pro or vice versa is not possible. A hardware mismatch error message will be shown. For a complete list of games up to X-MEN with their board numbers see Service Bulletin #178.
Games after X-MEN use the following boards:
| Game Name | CPU Bd. No. | I/O PWR DRV Bd. No. | 6-Trans. DRV Bd. No. | LED Bd. No. | U9 Pinball Boot ROM | Remark | |
|---|---|---|---|---|---|---|---|
| Avengers Pro | 520-5246-02 | 520-5249-00 | V2.0 | ||||
| Avengers Premium and LE | 520-5303-04 | 520-5317-00 | V2.0 | ||||
| Metallica Pro | 520-5337-01 | 520-5249-00 | 128MB V1.0 | same as AC/DC just has an updated bootrom | |||
| Metallica Premium and LE | 520-5337-00 | 520-5317-00 | 128MB V1.0 | same as AC/DC just has an updated bootrom | |||
| Star Trek Pro | 520-5352-00 | 520-5249-00 (Rev. D) | 520-5326-01 | none | 64MB V1.0 | ||
| Star Trek Premium and LE | 520-5352-01 | 520-5317-00 | t.b.d. | 64MB V1.0 | |||
| Mustang Pro | 520-5352-00 | 520-5249-00 (Rev. D) | none | 520-6822-00 | 64MB V1.0 | ||
| Mustang Premium and LE | 520-5352-01 | 520-5249-00 (Rev. D) | t.b.d. | t.b.d. | 64MB V1.0 | ||
| The Walking Dead Pro | 520-5337-01 | 520-5249-00 (Rev. D) | t.b.d. | t.b.d. | 128MB V1.0 | ||
| The Walking Dead Premium and LE | 520-5337-00 | 520-5249-00 (Rev. D) | t.b.d. | t.b.d. | 128MB V1.0 |
To make things worse, the boards for 50 Hz countries are programmed differently to prevent cheaper direct imports from the US. This essentially doubles all of the board variants. Thank you Stern. NOT!
S.A.M. is now at the end of its life. A completely new system named SPIKE™ has been developed based on an earlier revision of it being used in the Stern home model pinball machines referred to as "The Pin". This new platform is first used in the Stern WWE Wrestlemania pinball machine.
3.1.2 SAM I/O Power Driver Board
Power, fuses, bridge rectifiers. GI relay, coil and flasher drivers.
The adapter in the pic on the left is not part of the board and only used on the Stern White Star test fixture.
Starting with the LE and Premium edition games Stern now uses a new driver board. The lamp section in the lower left corner of the board has been replaced with a programmable Xilinx CPLD controlling the LED lamp boards. Due to this set up, 18vdc is no longer needed, nor is it present for controlled incandescent lamps. The 5V section has been completely overhauled also.
3.1.3 Display Power Supply
The SAM games equipped with gas plasma dot matrix displays use the same 520-5138-00 Display Power Supply as the Sega/Stern White Star games.
3.1.4 128 x 32 Dot Matrix Display
Because of the RoHS law, European models from POTC to Family Guy use a modified PinLED DMD. Later games use a 520-5052-05 Red LED DMD. Starting with Transformers, Stern games use a low voltage LED 128 x 32 dot matrix display (part # 520-5052-15). It's different from the -05 variant. It uses brighter Orange/Red LED segments and different TTL chips. The LED dot matrix displays are comprised of 64 discrete 8 x 8 LED matrix displays.
All US Stern games before AC/DC use a 128 x 32 "standard" plasma dot matrix display (part # 520-5052-00). With AC/DC, Stern also started to use LED DMDs in US models, completing the phase-out of plasma displays in their games.
- Stern Red 520-5052-05 LED DMD
- Stern-520-5052-05-Front.jpg
Front 
Back - Stern-520-5052-05-Segment.jpg
Close up view of the LED matrices used on the LED DMD
3.2 Recommended Documentation
As always, it is highly recommended to possess a game manual. Every game manual is full of detailed information regarding game specific switch, lamp, and coil assignments. Equally, details for maneuvering through test, audit, and bookkeeping screen menus, schematics for all boards used, and game specific mechanical assemblies are included. Hard copy game manuals can be purchased through several of the recommended pinball parts suppliers.
Since Avatar Pro Stern no longer includes printed manuals with it's Pro models. You usually get a few sheets of junk they call documentation but it's insufficient if you need to repair your game. The yellow section is mostly absent and schematics for newer boards are not included or useless photocopies (see AC/DC LE pdf files). Good luck if you have a problem here. You can only hope this changes again because the Pro modells are targeted to operators.
As of April 2014, The Stern website no longer archives PDF S.A.M. schematics. However, individual game manuals are available on their respective game pages. A game index can be found in the right margin on the "buy" page here.
Stern Pinball makes Technical Service Bulletins available on their website here.
3.3 USB Code Update
Note: this information can be found on the front inside cover of S.A.M. System Game Manuals.
Step 1) Open the Back Box
Step 2) On the CPU/Sound board set Dip Switch #8 to "ON".
Step 3) Press the white Reset Button (S1 RESET) or power cycle the game.
Step 4) The DMD should show the current software version installed. Press the "SELECT" button on the inside of the coin door to continue.
Step 5) Highlight the "UPDT" icon on the display and press "SELECT".
Step 6) The game will prompt you to insert the USB Memory Stick.
Step 7) Pick the correct file on the USB drive and press the "SELECT" Button.
Step 8) Follow the directions on the display.
Warning: If you live in a country with a power line freqency of 50Hz like any one in Europe do not update your game code when turning the game on for the first time ever. As of 2012/06/29 there is a bug in either the system or update code. Doing so will usually wipe out the country lock code from the game and the CPU needs to be exchanged. See Stern Service bulletin 170. Let it stay in attract mode a few minutes or play a few games with the old software first. This has been observed with a Batman Dark Knight and ACDC/LE.
3.4 Accessing Bookkeeping, Settings, and Diagnostic Modes
With the switch to the SAM system, Stern added a fourth switch to the coin door diagnostics switch bank. For people who are accustomed to entering diagnostics on Williams WPC games, this four button set up will feel much more natural.
Located just inside the coin door on the hinge side is an interlock style "kill" switch. This kill switch is used to kill all power to the solenoids, when the coin door is opened. Since it is an interlock style switch, it can either be depressed (when the coin door is closed), or it can be extended outward to turn the switch on. To extend the switch to the on position when the coin door is open, grasp the switch, and gently pull it out to the lock position.
This kill switch is a double pole switch. Wiring to one pole of the kill switch is BLK-YEL and BLK-YEL, while the other is RED-WHT to WHT-RED—yes, the colors do not match!
3.5 The New Stern LED Lamp System
Stern developed a new serial lamp control system for the release of Tron Limited Edition. This system uses a serial protocol to control playfield LEDs.
There are three components to the system
- the serial bus, which carries clock, data, power and strobe signals
- lamp boards, typically strips, which carry a serial LED controller for on-board LEDs and satellite LEDs
- LED satellite boards, which solder to the lamp boards.
The lamp boards daisy chain. Therefore, the controller can feed, say, 8 bytes of serial data to the lamp boards and strobe the data in, turning on or off 64 LEDs. This system is potentially expandable to hundreds of controlled lamps, breaking the constraints of the traditional lamp matrix. The lamp boards and LED boards can be assembled outside the game,simplifying the production and assembly of the wiring harness.
The controller used is an STP16DPS05. This device controls 16 LEDs, and uses a constant current output. Therefore, it needs no current limiting series resistors, although Stern has implemented series resistors on the satellite boards. [any ideas here?] The driver is also capable of reporting short and open LEDs, but it is unknown if Stern has implemented this feature.
In terms of diagnosis, one failed board could disable the entire system. The STP16DPS05 is a likely candidate for failure if an LED satellite board tangles with GI or other voltages. Replacing the chip is tricky as it has a full-contact heat transfer pad on the underside, which is difficult to heat properly without hot air or IR equipment.
It may also be useful to have a z-connector on hand to jump around a failed board. This will result in incorrect light patterns, but will at least demonstrate that the system is driving the daisy chain.
3.6 Optional Accessories
3.6.1 Knocker
The "token dispenser" option transistor can still be used to drive a knocker, and the body of the game still has a connector for the signal. A step-up circuit is required because Q24 is a low-voltage output. 520-5254-00 does a good job, but it means finding connections for solenoid ground, solenoid +50V, and solenoid +20V (if your board is the newer revision, which the new ones are).
On the new-style mostly-metal heads (Star Trek and later) there is no good place to add the knocker in the head anymore.
See also Sega/Stern_White_Star_Repair#Adding_a_Real_Knocker_to_White_Star_Games; directions are similar, but not quite identical.
3.6.2 Slam Switch
Most SAM games support an optional slam tilt switch, a feature missing on most Stern/Sega games back into the Whitestar era. The slam switch guards against abuse, but it also provides a convenient way to reset the game on ball 1 when it's not going so well.
On early SAM games, an optional switch can easily be installed to add the slam tilt feature. Part is 502-5032-00, available from parts suppliers including Marco. This installs neatly into the coin door with the center gusset surrounding the sticker with the game's name.
On later coin doors (the center gusset is gone, and the dollar bill validator blank is larger) there is no place to mount the switch, but the harness still has the optional slam connector. If adding a slam switch is still desirable, Suzo-Happ part 95-4176-00 can be used. This mounts over the lock. A connector will still need to be added to go into the existing harness, but no diode is required.
3.6.3 Tournament button
Early games (like WPT) have a tournament button on the lockdown bar. This may not be useful in home use, but it can be annoying to connect and disconnect when opening the lockdown bar. The entire "guts" of the button can be removed instead, keeping the button on the lockdown bar but making it nonfunctional, and making it easier to open the lockdown bar. Alternatively, Cliffy sells a kit for remounting the button in the dollar bill validator hole on the coin door.
Later games have the tournament button embedded into the cabinet below the start button.
Early games have a 5-pin .062 Molex connector in the coin door wiring harness for adding the button. A kit is available from the usual suspects that wires up to the hole on the lockdown bar. Marco lists this kit as 500-6587-06-TK.
Later games have a bunch of QD wires in the wiring harness, but they don't go through a single connector anymore. In this case, only the button is required. Pinball Life lists this part under a similar part number. The connectors are in the wiring harness leading to the coin door and can be pretty well hidden.
The switch between these two is (maybe? probably?) when the tournament button moved from the lockdown bar to the front of the cabinet. (Wheel of Fortune may be the game where this changed?)
3.6.4 Shaker Motor Kit
A shaker motor can be added by using either a genuine Stern shaker motor kit or a third party shaker motor kit.
Genuine Stern shaker motor kit
If you have a machine with a damaged or worn out shaker motor, you can purchase just the "motor only" to repair your machine's shaker motor.
3.6.5 Playfield Slide Brackets Kit
Some PRO models did not come with playfield slide brackets. Without them, it is difficult to service things at the rear of the playfield. Pinball Life has reproduced these brackets as a set. Once installed, it's much easier to service things at the rear of the playfield.
SAM cabinet Playfield Slide Brackets Kit
4 Problems and Solutions
4.1 Power Problems
4.2 MPU boot issues
4.2.1 Game with CPU Rev F resets during game play
This is mostly a problem with CPU boards from World Poker Tour. The first boards had a problem with the Flash ROM which caused random reboots or lockups during gameplay see Service Bulletin #163.
The service bulletin doesn't show which changes were made or which boards are affected. Unfortunately not all boards seem to have been modified at this point in time. A used game which has the old CPU in it can still be bought, either because the operator was lazy or swapped boards. Stern doesn't seem to be interested in fixing the problem free at charge after 8 years, and doesn't even respond to queries about it.
So if this problem is experienced, first check if the board is one of the affected boards. If the CPU is 520-5246-00 Rev. F, it's a likely candidate.
Next, check if it has already been modified. See if a thin green wire goes to the chip at location U44. This is the 29GL256N Flash ROM which holds the game code. There are usually two other green wires near the power connector J11 from an earlier factory hot fix which have nothing to do with this problem. They deal with RAM issues and all Rev. F boards should have them.
If the modification has not been made, try first to resolve the issue with the seller or Stern. If the issue cannot be resolved, continue below.
To modify the board, experience in SMT soldering of very fine pitch parts is needed. Also it's a $500 PCB, so if something goes awry don't blame PinWiki.
Two modifications are needed on the front and back of the board:
First, cut the trace at location 1 on the backside of the board. This is going to the OE# pin 34 of the 29GL256. It will need to be rewired to the NRD/NOE pin 49 of the U42 Xilinx CPLD. To do this run a wire between location 2 and 3. Check the work by measuring continuity between pin 41 of U13 and pin 34 of the Flash ROM.
Next comes the tricky part. CE# pin 32 needs to be rewired directly at the Flash ROM. Location 4 at the front picture. First cut the trace at this pin. It's the fourth counting from the right and is around 5mm long. It's connected to ground, so double check that it's open after cutting, or damage of U42 will likely occur. Then, run a wire from pin 32 to location 5 on the picture. This is the original trace previously running to pin 34. It's the chip select for the Flash ROM pin 71 GF0 coming from U42.
This modification properly connects the Flash ROM Output Enable and Chip Select pins. Something which Stern should have done in the first place. Also the schematics are wrong and don't show this. Revision G CPUs still had this and some other modifications done by the factory. Only with Revision H the pcb was changed and the schematics on Sterns website and in all manuals only show the revision G CPU. The barely readable Avengers LE schematics show the correct wiring for the Flash ROM despite being for the later SAM CPU with different USB.
While it runs stable afterwards there is unfortunately a problem with this modification. The Flash ROM can no longer be written to. Updates will fail. OE# needs to be held high during a write cycle and this doesn't happen. To remedy this, it is likely that U42 will have to be reprogrammed. The owner of the modified board here had the latest WPT update already flashed, and didn't want to risk bricking it so this has not been done yet.
4.2.2 Game with CPU Rev F or G does not boot
As stated in an earlier section the Rev. F and G 520-5246-00 CPUs had the chip select inputs to the Flash ROM modified. If your game doesn't boot check if one of the two wires for the modification has come loose. This can happen because not enough solder and/or flux was used doing the connections. This can be verified by putting the game into update mode (setting dip switch 8 to ON). If the CPU boots here check the connection first.
4.2.3 Relocating the battery from the MPU board
The Stern S.A.M. system uses a single 3v lithium CR2430 "button cell" for its memory backup. These cells have very long life and are not prone to electrolyte leakage so you do not need to do this.
If you really, really want to relocate the battery, use a 2 cell holder, with two AA batteries. No blocking diode is required.
4.2.4 Connecting a logic probe to the MPU
4.2.5 Using a PC Power Supply For Bench Testing
4.3 Game resets
4.4 Solenoid problems
4.5 Lamp problems
If you have a bulb not working, seat the wiring into the IDC type socket better. I've run into a lot of these where the wires aren't seated and making good electrical contact.
4.6 Switch problems
If a switch isn't working. The three most common things I've seen is. 1- crappy switch, even if new. 2- if wires go into a IDC connector nearby, be sure they are seated good and making electrical contact. 3- broken wire at switch, or inside casing or harness, easy to quick check continuity of wiring.
4.7 Display problems
4.7.1 DMD LED to Plasma conversion
Starting with Pirates of the Caribbean, Stern replaced the normal Plasma Dot Matrix Display on European models with an LED variant because of the RoHS law. They first used PinLED DMDs, and later, switched to a red DMD specifically made for them (520-5052-05). The debate which looks better will be going on for your remaining lifetime and continue right into your next few lives, but here, we show how to replace the LED DMD with a standard Plasma Dot Matrix Display.
The following parts are needed:
- 1 x 520-5138-00 Stern Display Power Supply Board
- 1 x 036-5454-01 SAM DMD Display Cable
- 1 x 535-9769-00 PCB Metal Mounting Plate (Display)
- 1 x 830-6053-00 Plastic Cover Danger High Voltage
- 2 x 254-5000-05 1-1/4" x 3/8 Plastic Spacer Grey
- 2 x 237-5975-00 #8 x 3/8 SHWHSec (Zinc) Screw
- 2 x 02-4425-2 Machine Post/Stud standard metall threaded posts with #8 bottom and #8 top (for the gray spacers).
- 2 x #8-32 Nylon Insert Lock Nut
- 4 x #6 x 1/2" Wood Screw to mount the unit in the backbox
You can get all these parts from your favorite pinball dealer. I got them from Pinball Life. If they are not on the web page, ask.
You need to first assemble the High Voltage unit. Assembled it looks like this one here:
- Stern SAM High Voltage Unit
View 1 
View 2 
View 3
Just screw it into the backbox of your Pinball over a ground strap:
The cable which goes into the left side is somewere hidden in the wiring harness of your pinball:
The LED DMD plugs into your wiring harness with a 2 pin connector. You need to remove the connector and connect the 5V line to you DMD HV unit. You should find the corresponding 2 pin plug which matches the one on the picture nearby. Warning: the wires should be red and black. At least in Family Guy and Shrek there is a similar connector with 2 brown or black wires with color stripes nearby. This one is for the optional knocker kit. Make sure you do not connect this one to your DMD 5V line. Doing so will take out the DMD and the SAM CPU beyond repair! If unsure measure the voltage on this connector first.
If your game uses a PinLED LED DMD, a small PCB is connected to connector J5 on the SAM CPU. Take this one out and install the ribbon cable directly in J5 on the SAM CPU. Now you just need to replace the DMD with a standard plasma DMD and, voila!, it should work.
4.7.2 LED DMD bad vertical line
If a game is always showing a semi-bright vertical line on the DMD, usually one of the LED segments is bad. Fortunately the bad segment can be found easily. As shown in the picture to the left, one pixel in the line is always dark. This 8x8 segment is the bad guy and needs to be replaced. The good thing is that this problem usually occurs with NIB games just after a few hours or days of game play so the DMD is still under warranty. If not, ask Stern for the availability of the LED segments. When replacing a block, be advised that the vias are small and are difficult to remove without the proper equipment.
4.8 Sound problems
4.8.1 No Sound
A problem which has been seen in both first and second generation S.A.M. boards is a complete loss of sound in an otherwise completely working system. Reflashing the system will not correct this and even though all voltage lights will be illuminated and the game plays normally, there will be no sound. This problem has been traced to a failure of the PCM1755 D/A converter at U16 on the S.A.M. board. If your system is showing these symptoms, the only solution is to replace U16 which is a 16-pin SSOP (shrink small outline package). This is a very small surface mount component that measures approximately 5 x 6 mm (including the chip legs). As a result, its replacement should not be attempted without the proper skills and equipment. Normally, replacement of this component will return the sound to the system.
4.8.2 Volume Control Bug
In early SAM games, if the simulated knocker is activated (the annoying loud "twip"), the sound level may increase to full volume after a replay is awarded. This is a bug in the basic operating system code. The bug was fixed in newer games but Stern didn't release updated ROMs for older games. This bug has been observed in WPT, Family Guy and Shrek. The workaround is to disable the simulated knocker. If a knocker sound is still desired, a real knocker can be installed as the games support it.
4.9 Flipper problems
See Common Flipper Troubleshooting for general flipper information.
Like Stern's previous system, flipper coils in SAM games are solenoid coils that are duty-cycled. Unlike traditional flippers, the flipper coil is single-wound like other solenoids. The initial "kick" is done at full power, then the coil is software duty-cycled to keep it in the "hold" up position. The EOS switch serves to tell the game when it needs to re-kick the flipper.
Unlike other systems (including WhiteStar), no diodes are required to be on the flipper coils. These have been incorporated into the solenoid driver board. A diode on the flipper coil indicates likely replacement. It won't hurt, but it does provide an opportunity to wire the coil backwards.
Mechanically, the flippers are identical to the WhiteStar flippers and use the same parts. (The design is very similar to the Williams WPC/System 11 design.)
Major wear points are the coil stop, flipper link, and coil plunger. If these have deformed (and they will, because a flipper essentially pulverizes itself during game play), the flipper will lose power and won't play as well. Every few thousand games, a rebuild kit can be installed to restore the flippers to factory performance.
Coils hum. (They jiggle in their mount.) The way they are power cycled causes some of this. They get noisier with use. Filing the plunger end and coil stop smooth can alleviate this, as would a rebuild kit.
4.10 Pop bumper problems
4.11 Opto problems
Stern's SAM era optos are a bright, visible red. Unlike Williams', Stern (and Sega and Data East) chose to show the switch as open when the opto receiver can see the sender's light, like any other switch.
Optos are connected to a board in pairs. Both the sender and receiver are the same part, so one way to verify if the receiver is working is to plug it into the sender's pins. That is, just reverse the two cables.
A common failure point for optos is that the wire breaks at the opto sender or transceiver itself. These will have to be soldered back on. Typically, the wire seems to be plain old speaker wire. The copper-colored conductor goes to the cathode 'K'; the anode 'A' gets the silver wire.
4.11.1 Opto board 520-5292-00
If there is trouble with the switch matrix, check this little opto board. It's installed in at least Batman Dark Knight, AC/DC, and several in The Rolling Stones (one is used for each position the moving Mick stops). In AC/DC, a bad board can give problems with at least the bell and the right pop bumper. If the pop bumper turns on when the ball is shot into the bell, the board is bad.
There is not much on the board. If there are general switch problems, the likeliest candidate is Q1 a BSS123 in a SOT-23 case (small) transistor. Check it with a DMM. It's a Mosfet so can not be completely checked with a DMM. On the defective board, the drain to gate pins were practically shorted.
If the opto interruptor just doesn't work, it can be replaced with a QVE11233 from Fairchild. It's the standard opto for WMS flipper boards, which is now discontinued. Stern also used a chinese substitute OS92B4. Not much can be found about it.
4.12 Trough problems
The trough design on S.A.M. games is identical to what was used on Whitestar games. See Sega/Stern_White_Star_Repair#Trough_Opto_Boards.
Stern opto boards at end of trough. And boards playfield optos plug onto. I've noticed when problems arise, to reflow the solder on the optos, and pins the connectors plug onto. This eliminates a lot of problems that arise with the optos. LTG :)
5 References
As of April 2014, SAM system schematics are no longer available on the Stern Pinball website.
Older manuals still have complete schematics and can be useful for troubleshooting newer games. The SAM boards did change, but connector designations generally didn't. Some manuals may be available from public sources in high-quality PDFs originally distributed by Stern Pinball.
6 Game Specific Problems and Fixes
6.1 Pirates of the Caribbean
The spinning disc. Check your serial numbers with the service bulletin on Stern's website. Some of the early games need to have the bearings lubricated.
And if your artwork is worn off. I've found when you put on a new decal. To put clear non-slip bath tub stuff on top of it. It works just as good at flinging the balls. And doesn't wear off as fast and get messy all over the game like the original. And easily replaced. LTG :)
6.2 World Poker Tour
I bought a World Poker Tour that had been routed. When I got it, the "jail" detected balls on power-on that weren't there. Cleaning the upper playfield made it happy, since the optos assume they can see through the clear playfield. I replaced the whole upper playfield in late 2014. After a few hundred plays and three trips to California Extreme, the upper playfield was dirty enough that this problem happened again--or at least the switch became flaky. A little cleaning "fixed" it. But it's likely this will require additional cleaning every few hundred plays. ts4z (talk) 03:07, 25 November 2017 (CST)
WPT's drop target banks may need some washers inserted as shims. Stern published service bulletin 165 with the details. ts4z (talk) 15:35, 4 November 2014 (CST)
6.3 Tron Pro
Spinning disk motor dead, no power going to it. Found someone had oiled the motor which had then slung oil everywhere. Discovered oil had leeched inside the spin disc relay (assembly # 511-6919-01), burned the contacts, and blew transistor Q5 (IRL540) on the power driver board (fuse F6 was blown too). I popped the cover off the relay and cleaned out the oily mess with 99% isopropyl alcohol. Then I filed the burnt contacts and reassembled the relay. Next I replaced the bad Q5 transistor and blown fuse. That fixed the problem and the motor works again.
7 Repair Logs
Did you do a repair? Log it here as a possible solution for others.
7.1 feature lamps not working
If you have feature lamps not working. Check the wiring pushed into the lamp socket. I've seen more than a few where the wire isn't making good contact where it is pushed in. Easy to push in better. LTG :)
7.2 bad opto board
I got a brand new Star Trek. After a couple days of being played at a show, the game's technician alerts reported the left ramp entrance as not registering. After I got the game home, I discovered that the under-playfield indicator on opto board 2 registered fine (it's on until the opto is blocked, then it shuts off), and grounding the two switch matrix switches registered the switch. So there must be a failure on the board. Stern tech support sent a new board under warranty and that fixed the issue. ts4z (talk) 02:28, 30 July 2015 (CDT)
7.3 Battery draining quickly
A SAM CPU board was rapidly draining the battery when the game was powered off. Power was getting from the battery to the clock at U43 and the RAM at U11. In other words, the components on the way to the clock and RAM were good (R211, D24, R212) and the diode at D25 was also good. However, when setting the time under the Utilities menu, gibberish would be output when the last entry was accepted. This indicated a problem with the clock IC at U43. The clock is a SOIC-8 150 mil package. A replacement is DS1302Z+ found at mouser.com. After replacing the clock IC the game kept correct time when powered on and off, and the battery no longer drained quickly. Stangbat (talk)