Sigma SG300 Treasure Wheel problem

[RV Doctor]

Recently my SG300 Treasure Wheel started intermittently giving me the error message: "Coin-In Reverse". This would happen even if I wasn't playing with coins but just using credits.  I'd turn the machine OFF/ON and/or open the door, and the error would vanish.  However the frequency of these errors was increasing.   I noticed that the single soldered-on 3.0V CPU battery was only about 2.7V so I replaced it.   At the same time I noticed that the rightmost conductor on the ribbon cable going into connector CN18 (on the CPU board) was broken.  I repaired the wire and powered ON the machine.

The reels would do their start-up spin and the lights on the treasure wheel would flash. The display would say "Game Loading, Please Wait".  Everything appeared normal.  But then the "Winner Paid" and :Credits" displays would both go blank and the speaker would start giving a sound like a 20 Hz buzz mixed with static.  The LED on the MC-40 would go orange.  I removed the (previously broken) pin on CN18 but this symptom persisted. I reinserted the previously broken pin and still my problem persisted. (ie. no change in symptom).   I reseated the connector on the MC-40 coin acceptor and suddenly everything worked great.  The LED on the coin comparator was green, and all functions of the machine performed 100%.

After about 10 minutes the light on the coin comparator went orange, and the funny sound on the speaker returned and the "Winner paid" and "Credits" displays both went blank.

Now when I turn the machine ON the reels don't spin, the "Winner Paid" and "Credit" displays are blank, the main display shows an underscore in the top left position, and the speaker immediately sounds like a 20 hz hum with static.  The lights on the treasure wheel are flashing constantly, and the LED on the MC-40 coin comparator is orange.  Using the reset key has no effect. Coins fall through the coin acceptor into the tray.

Does anyone have any thoughts on this?

RV- Doctor

[jay]

Knowing nothing about Sigma.... but it Sounds like you might have a bad comparitor especially if it errors out during credit play. I would have gone with bad optics had you not indicated the Orange light on the comparitor
Can you simply unplug the comparitor and see if the machine functions ?

[RV Doctor]

Unfortunately, unplugging the coin comparator does not change the symptom.  Nice try though.


....The RV Doctor

[KirkLasVegas]

Place a bet for me on the nose of the "POWER SUPPLY"....
Seriously, Check the voltages and (if you have a scope) look for ripple.The low frew hum/buzz is concerning....

Kirk

[RV Doctor]

The power supply output voltages are all fine. They are accessible at test points (TP) 1-4 at the edge of the CPU board. The 5V and 12V levels were 5 and 12V respectively. The 24V level was 25.5V but I don't think this is enough of a variation to cause problems.  The AC ripple was less than 0.0 VAC on all the test points.  I have tried several "tricks" from other slot folks and I can now get the machine to start it's power-up cycle. The display says "Game Loading. Please wait a minutes". The reels do a test spin. The speaker plays the correct "spin sound". (no static/hum noise) However when the reels try to spin to their previous position, the game locks up. The Credit and Winner Paid counters go dark and an "underscore" is the only lit segment on the alphanumeric display panel. The speaker immediately makes this low frequency buzz with a static overlay.

However I have noticed that there is a 7 segment display on a PCB mounted on the side of the power supply.  (A seven segment display looks like a squared-off number 8)  When viewing this "number 8" , two of the segments are flashing. The flashing segments are; the lowest vertical segment on the right side, and the highest horizontal segment.  Do you have any sort of fault dictionary that explains what these flashing segments mean? My Sigma manual doesn't cover it.

Any thoughts?     .....RV Doctor

[Randy0777]

Any chance you have another Sigma (150 or 300) ?