S+ (sort of) dead after LED conversion? NEEBIE NEEDS HELP

[GreenAdam]

I'm totally new to the slot machine thing - just purchased a 1999 model S+ a few weeks ago.  The machine worked fine after hauling it to my house and plugging it in.  But then...


In order to cut down on the power usage, I switched the fluorescent tubes over to LED tubes... but I didn't do the smart thing and buy the bulbs that don't require removing the ballasts and other stuff.  This meant the machine was unplugged for a few days while I removed the ballasts (looked like a transformer to me) and the starters/condensers.  I wire them to be 110 volts to the LED bulbs as required.  Once this was done, I plugged the machine back in, flipped on the power switch, and the LED lights look and work great.


BUT... there is clearly something wrong with the machine now.  I saw the "coins played" LED display show the number 1 for a short period of time, but then it turned off and the LED display is now completely blank.  Turning it off and back on makes no difference - not even a flicker from the LED display anymore.  However, I can see that the general illumination bulb in the center back of the LED display board still lights up.  Only the center one, but it's possible the other bulbs are shot and I didn't notice.  And yes, I checked all 3 fuses (with a multimeter) and all 3 are fine.  When I turn the power switch on now, the LED lights fire up fine and I can hear the bill validator go through its whirring and clunking procedure.  But that's it.


MAYBE or maybe not related, but I just checked the battery on the main board and it is really, really shot - measuring 0.24 volts.  I'm ordering a replacement now, but I have no idea if the dead battery is the entire problem or completely unrelated.


Please tell me that the transformers that powered the old fluorescent bulbs didn't also power something else that I have now FRIED!

[knagl]

I don't know for sure if you've fried anything, but I'd start by removing the new LED tubes you put in and seeing if the machine behaves any differently when you turn it on.

Also, yes, if your battery is that low, you'll need to replace it.  That said, a low battery should give you an error 12 on the LED display, not a case of no display.  Finally, if your machine was working just a few days ago, it is unlikely that your battery voltage dropped that much in just a few days.  Could it be reading 2.4v, by chance?

[therockinelvis]

While the machine is on, open the door and see if the reels are tight or free spinning. If free spinning it could be your cable from the power supply to the mother board in the bottom of the machine. See picture and pull the plug to see if it is burnt. Picture has the plug turned backwards to see the burn.

[GreenAdam]

I checked the battery a few times and it's definitely reading 0.24 volts.


I have the motherboard out of the machine to replace the battery, so I can't try to start it right now without the LED tubes, but I do know for sure that the reels will NOT spin freely when the power is on.


Any other ideas to try?  After this started to happen, I thought I detected the faint smell of something electrical burning.  But the smell was VERY faint... and may have even been my imagination since I was thinking "I sure hope I didn't fry anything!" at the same time I thought I smelled it.  The power of suggestion, you know.

[cowboygames]

Don't those LED tubes plug into 24v DC?

[Shaggy]

The mother board is the board that is connected to the bottom of the machine. You have the MPU or CPU out. That is what holds the battery and connects to the mother board. The one Elvis is talking about is the one in the floor of the machine.

Dave

[GreenAdam]

Don't those LED tubes plug into 24v DC?

Not the ones I have - they require a full 110 volts AC.

[GreenAdam]

The mother board is the board that is connected to the bottom of the machine. You have the MPU or CPU out. That is what holds the battery and connects to the mother board. The one Elvis is talking about is the one in the floor of the machine.

Dave

OK, got it.  My bad!  I'll take another look.

[cowboygames]

Not that you shouldn't do as stated above as far as memory battery replacement, just wondering if the new lights turned on

[GreenAdam]

Not that you shouldn't do as stated above as far as memory battery replacement, just wondering if the new lights turned on

Yes - new lights turned on and look outstanding!  So my machine currently looks great, but won't play.

[therockinelvis]

I checked the battery a few times and it's definitely reading 0.24 volts.

With the battery that low, it's a wonder it had played at all. Very odd that displays are not lit to show error. Your lights being 110 volt should not effect the displays. Just to be clear, when you turned it on, the lights and bill validator work. Did the reels spin?


Fixed a quote box issue.  -knagl

[GreenAdam]

I checked the battery a few times and it's definitely reading 0.24 volts.

With the battery that low, it's a wonder it had played at all. Very odd that displays are not lit to show error. Your lights being 110 volt should not effect the displays. Just to be clear, when you turned it on, the lights and bill validator work. Did the reels spin?


Fixed a quote box issue.  -knagl

Yes - when I turn the machine on, the lights turn on just fine and the bill validator makes it's normal whirring/clunking sounds for a few seconds and then goes silent (like normal).  The LED screen stays completely blank.  When I try to put a coin in the machine, it drops straight through into the coin tray below without making a sound.  Pushing the "spin reels" button does nothing at all.  I've noticed that the reels do not spin freely when the power is turned on.


One more clue that I failed to mention before:  immediately after this problem started, the reels were occasionally "twitching" for a period of time - like one of the reels would have a slight muscle spasm, it would stop and nothing would happen for a few seconds, then a different reel would twitch, and repeat.  The next time I tuned the machine on (and every time since then), the reels don't twitch.


Any ideas or things to try?  I do have a high end multimeter and an oscilloscope if you have any tests to suggest.

[cowboygames]

I don't think I'd mess with it a whole lot till you get the new battery in. Just for good measure, check the power supply fuses and maybe the plug connection between it and the motherboard, but beyond that not much. You know the battery is one issue, take care of it first, then move on

[knagl]

Have you tried turning it on with the new LED bulbs you installed removed?

[GreenAdam]

I don't think I'd mess with it a whole lot till you get the new battery in. Just for good measure, check the power supply fuses and maybe the plug connection between it and the motherboard, but beyond that not much. You know the battery is one issue, take care of it first, then move on

Very good point.  I'll put in the new battery and see what I get.  If nothing has changed, I'll try pulling out the LED tubes and see if that makes a difference.

[GreenAdam]

OK, I finally have the new battery installed and nothing changed.  I had the MPU out of the machine entirely when I flipped the power switch on a little while ago (by mistake) and it was interesting to see that this didn't change anything with how the machine reacted to being powered on - all the same noises, LED lights still light up just fine, bill validator still makes the same noises, etc.  It makes me seriously wonder if the MPU is even getting power at all!


I've also checked the white connector on the motherboard and don't see any issues.  No burned spots, no wires out of place, etc.  Fuses have just been tested good (for the third time).


Going back to the very basics:  how do I even check to see that I'm getting the right amount of voltage to the right place??  Should I be able to measure certain voltages between the different wires inside the white connector?  I just want to verify that the motherboard has the right voltage going into the right place as a starting point.


I've got power supply schematics that I've reviewed in details, but I'm struggling to connect the details shown to the actual machine!  It shows a transformer with various voltages coming out, some leading to a "tray transformer", a few different test points... but are those test points located inside the power supply box?  On the motherboard?  Forgive me - I'm a mechanical engineer, so it's taking a while for my brain to switch into electronics mode!

[GreenAdam]

OK, I already answered my own question - I found a thread with the details of what each line from the power supply to the motherboard should be reading.  All three of the voltages (24 VAC, 7 VAC, and 8 VAC) were measuring a touch over 1 volt higher than they are supposed to be (measuring between each "hot" line and the corresponding "common" line for that voltage level... with 7 VAC and 8 VAC both sharing the same common).  Any idea if this extra 1 VAC makes any difference at all?  Does this have the possibility of frying something downstream?  Seems unlikely, but I'm hardly an expert.


I also forgot to mention that I found a thread where it's possible to measure the voltage across one of the capacitors on the display board to look for the correct 8-10 VDC.  I performed this test and measured only 0.65 VDC with the system powered up!  That's obviously a problem, but I don't know where to track this back to.


Looking for suggestions!!  This sucker won't beat me.

[shortrackskater]

Exactly what happens when you power off, then on. Is there any CODE showing in the display?

[GreenAdam]

Exactly what happens when you power off, then on. Is there any CODE showing in the display?

Nope - the display is completely blank no matter what I do.  The (used to be fluorescent) lights light up, the bill validator makes some start-up noises, but that's it.  The reels are not free to spin, but that's the only sign of life that I've found.

[GreenAdam]

Does anyone know if diode D2 on the processor board measures as a dead short in both directions when still soldered into the PCB?  I noticed that I'm reading very little resistance across this diode and switching which test lead is on which side of the diode makes no difference.  Is this normal when still soldered into the circuit?


I'm waiting for my new desoldering tool to arrive in a few days, so I can't pull it out and test it quite yet.  Just curious to see if anyone could tell me if this was the smoking gun problem that I've been hoping to find!