S+ No Display

[thanksaslot]

I'm trying to troubleshoot a friend's S+ reel machine.  On power up only the fluorescent lights work.  Supposedly everything was working normally, then simply was not working next time it was powered up.  No LED displays, reel activity or sound.  I have verified 3 power supply fuses good and AC power on the convenience outlet.  No visible problems on the main board and the battery voltage is good.  It appears that it will be difficult to troubleshoot main board power supplies, etc. since the board is enclosed in the metal shell and must be unplugged to access.  I have technical ability so I’m open to any suggestions of things to check or how to do so.  I don’t see any obvious test points or such to check power supply voltages, for instance.

[Stayouttadabunker]

The fluorescent lighting runs on the 115VAC lines...separate from the power Molex on the motherboard (The board on the floor that the MPU plugs down into).

There's a white 6-pin Molex power plug housing that comes directly from the power supply box into the male pins on the motherboard.
I'm assuming you have an somewhat newer S+ that has the large rectangular Power Supply box on the floor of the right-hand side of the cabinet under the bill acceptor cashbox?
Wiggle it upwards slightly while watching the reel baskets...if while wiggling upwards upon the male pins, and you see the reels "jiggle" like they're being powered on, then you might need to get yourself a new power supply harness.
Wiggling the white connector upwards is an attempt to get the female pins inside to get a different electrical contact on the male motherboard header pins.
If you pull off that power Molex & turn it around, you may see one of the pins has browned the white housing...
That's from the female pins inside getting too loose over the years from grasping onto the male pins.
NLG member Trisail makes these power harnesses with brand new trifurcon female pins...get ahold of him, and ask him if he has any.

Anyways, here's a photo of the white 6-pin Molex power supply connector I'm talking about.

Click on photo below to enlarge if needed...>>>

[thanksaslot]

Thank you for the speedy reply.  I will have an opportunity to try your recommendations next week.  I'll post my findings.  Again - thanks!

[thanksaslot]

Your advice about the power connector was spot on.  I unplugged it and inspected for signs of overheating and found none.  I measured roughly 24VAC across various combinations of terminals so it appears the AC power supply is working.  Upon reconnecting and restoring power, the unit started partially working as it had LED display activity and the reel rotation and subsequent tension.  Must have been a high resistance connection.

I say 'partially working' because after initial startup activity I have a "1" on the Winner Paid display and a "3" on the Coins Played display.  Inserted coins drop right through to the coin tray.  No other activity or responses to button presses or handle pulls.  I do have a pdf of the S+ service manual.  Any advice on where to start for troubleshooting?  Looking at Section V is there a particular option group I might zero in on?

[sixcardmark]

Is there a sample coin in the coin comparitor?

[thanksaslot]

Yes, there is a coin in the sample comparitor and it appears to be situated correctly.  I noticed there is an LED on the comparitor module, which is not lit.  To reiterate from my OP, supposedly this unit was working fine and then failed to turn on recently. So I'm working on the assumption (that can get me in trouble) that things like the comparitor sample were not disturbed.  But it certainly doesn't hurt to ask and to verify.

Would it help to remove the sample and reinsert it?

[sixcardmark]

I would try a different quarter or whatever is in it.  For some reason that works sometimes.

[thanksaslot]

I will give it a try.  Thanks for the help.

[Stayouttadabunker]

Coins dropping straight thru back into the coin tray tells me that the rake on the back of the CC is not getting pulled in.
The coins get rejected as the rake stays stationary, and re-directs the coins out to the right-hand side of the coin mech, down a chute back down into the coin tray.

SCM suggestion is good about replacing the Sample Coin....sometimes that's all it takes.
I would also try wiggling the small 2-pin connector on top of the CC that has the two gray wires coming out of the back of it.
Those two gray wires are for the magnetic coil on back of the CC that pulls in the rake.
Sometimes wiggling that small connector off and on of the pins, promotes better electrical contact with the male/female pins inside of the housing connector.
Hopefully, you'll get better electrical contact and the rake will allow the coins to slip by to fall directly downwards on the left-hand side of the CC into the coin-in optics below.
The coin-in optics board below is where you need to coins to get to, to register coins as credit, back to the machine.
Right now, the rake is bypassing coins aside of the coin-in optics.

Finally, if the doing all of this doesn't work, you can can, unplug the CC harness, and route the harness out thru the front of the door somehow....usually thru the bill acceptor hole in the door?
The LED light on the CC only comes on when the main door is in a closed state.
If the LED light comes on when the door is closed, at least you know it's getting power.

Also, turn the coin sensitivity dial all the way counter-clockwise for better coin acceptance.
(The rake behind the CC will always open.)
The correct coin sensitivity dial adjustment on the coin comparitor for an U.S. quarter, is roughly about a 1/4 turn clockwise.

Another thing that causes problems is that bottom black wire on the CC harness.
It gets played with a lot but people tend to pull on the wiring, rather than the connector body.
The black wire could possibly be broken uner the covering.
The best way to check it is to use a multimeter to see if there's continuity in that wire from one end to the other.

[Badbaud]

Yes, there is a coin in the sample comparitor and it appears to be situated correctly.  I noticed there is an LED on the comparitor module, which is not lit.  To reiterate from my OP, supposedly this unit was working fine and then failed to turn on recently. So I'm working on the assumption (that can get me in trouble) that things like the comparitor sample were not disturbed.  But it certainly doesn't hurt to ask and to verify.

Would it help to remove the sample and reinsert it?

The coin comparator light only comes on when the game door is closed and locked.