Author Topic: help with igt s+ erratic behavior (Read 3726 times)

alrolon800 · « **on:** March 17, 2018, 08:48:14 PM »

I have a double diamond slot. 10 MHz S+... mpu battery changed before I got it. cleared ram but acted erratic with front led's flickering and counters clicking like crazy. wheels lock in place. checked 6800uf caps. one leaked so changed them all out and Same problem. checked diodes and one nte5812 was open. replaced and same problem. I did get it to count up to 999 and after that went erratic again like a cold solder problem. physically checked mpu and motherboard with magnifier. found nothing. its like it locks up after being on for 5 min or so then I cant clear mpu till I leave it off for a couple of hours. Best I got was 61 code. put game eeprom back and just locks up again like intermittent power problem. checked AC voltages to mpu and all are fine both when I turn on and later when erratic behavior starts. could it be wheel spin chip or cmos chip bad? or board shot? all fuses are good. it will ding and start clear process with the count to 999 all by itself when turned on but during second countdown starts flickering then goes blank except for the first zero on the display. if I leave it for ten minutes relays click and counters start counting, Weird and I need help. Al

ItsaSlotMachine · « **Reply #1 on:** March 17, 2018, 09:00:27 PM »

I'm thinking that if you have error 61, you might try opening and closing the door and that might clear the error. I am not entirely sure on that but I've heard that it works sometimes to clear errors. Also the light bulbs may need to be replaced all together in the front panel. Sometimes, light bulbs go on and off like rapid before they go out. That happened to one of my living room light bulbs before it brunt out. Somebody with more technical knowledge may be able to help you even more with be chips.

alrolon800 · « **Reply #2 on:** March 17, 2018, 09:26:02 PM »

Thanks but I was referring to the LED's that give the codes start flickering. problem seems to be electronic with either the power supply, a cold solder joint, bad eeprom or mpu just went bad. error came up once. when machine gets warm it locks up completely. when cool it will try to start the clear process and then stops and gets erratic.

Badbaud · « **Reply #3 on:** March 17, 2018, 09:47:22 PM »

That is the same voltage the door optics uses.
Check the molex header that the transformer plugs into and make sure the pins are not corroded.
The next check would be to see if one of the power diodes has shorted near the power input header.
Next would be to use a scope and see if one of the large filter capacitors is failing and causing to much DC ripple.

alrolon800 · « **Reply #4 on:** March 17, 2018, 10:13:40 PM »

Hi, all caps changed out. one diode was open (not shorted) and replaced with new. Molex to power supply and motherboard checked good. Voltages of 13vac 12.8vac 8.5vac and 7.5vac all check out good from molex at motherboard. that's why I asked if maybe reel eeprom is bad. machine came to me with original tamper tape on all three ic's. tried sp731 I got with clear chip and same result. even if door switch were bad it would stay on 61 and not go erratic with relays clicking and counters counting and leds flickering after 10 minutes powered up.

alrolon800 · « **Reply #5 on:** March 17, 2018, 10:47:05 PM »

last note before bed. battery was changed out before I got machine. but maybe put in backwards first shorting out cmos. Or mpu board was pulled with power on. this wouldn't burn boards but fry eeproms. I changed all caps because one was leaking with brand new 6800uf 25v. machine dings when turned on and tries to count with leds working nicely then flickers and goes out then dings again like its clearing for a second time but without led's. problem is the machine does not wait for me to hit the spin key. it starts clearing when turned on. I only then get a zero on far left red LED. Tells me power is good but maybe a bad IC when it gets warm and shorts out. then I have to leave machine off for an hour or two before I can get the ding "clear cmos" sound again.

Badbaud · « **Reply #6 on:** March 18, 2018, 05:57:08 AM »

The battery voltage is diode protected. If a battery is put in backwards the reverse voltage does not reach the RAM.
The EPROM's do not run off of battery voltage.
Maybe you should send the board to us so we can evaluate it on our tester with a scope?

Shaggy · « **Reply #7 on:** March 18, 2018, 06:42:03 AM »

I had one doing a very similar thing with the displays flashing, counters etc. going on. A new battery had been installed, but at a closer look, there was acid damage to the board from the previous battery. It had been cleaned up but you could look close and see where it had run under the sockets and the traces were damaged. I swapped out a board from another machine, although not the same game type, but I just wanted to make sure the rest of the machine was good. It came right up and played. I cut my losses and replaced the board. My SP chip and SS chip were fine and I reused them. It's been running for years now.

Dave

alrolon800 · « **Reply #8 on:** March 18, 2018, 06:57:28 AM »

I just came across something interesting. in a previous help line was told AC voltages from power supply should be 13 vac, 12 vac, 8 vac and 7 vac.. but just found a diagram that says it should be 24vac, 24vac, 8vac and 7 vac. do you think maybe power supply is set for 220 input voltage?? Will remove today and check jumpers. will just need to know how or where jumpers should be for 110 volts input .

JWS · « **Reply #9 on:** March 18, 2018, 09:30:41 AM »

Symtoms sound like it may be a heat related problem. Would be a pain for access but a can of freeze-it may help isolate an area on the MPU that is having issues.

Badbaud · « **Reply #10 on:** March 18, 2018, 10:28:36 AM »

It could be the Vcc or Vbb Tranzorb is going bad. Try raising one leg out of the board and see if that helps.

alrolon800 · « **Reply #11 on:** March 18, 2018, 11:04:49 AM »

What I need to know is what are the output voltages for the main power supply running on 115 vac. I removed 220 jumper and still get 12 to 13 vac on molex plug on the MPU. I just read its supposed to be 24 vac and where is the vbb and vcc transorb located. please give me a location number. appreciate any help.

Badbaud · « **Reply #12 on:** March 18, 2018, 02:01:36 PM »

Vcc Tranzorb is large diode across Vcc (5V) and Gnd marked on the board.
Vbb Tranzorb is large diode across Vbb and Gnd on the board.

alrolon800 · « **Reply #13 on:** March 18, 2018, 06:28:31 PM »

Thanks badbaud, removed one leg on all diodes and all checked good. did suspect power supply because I get 2 opinions as to what the A/C output voltages should be from the transformer. one says 12-13 VAC from molex plug pins 5 and 6. Another says I should get 24vac. I really think they mean 24vac between pins 5 and six. as that is what I get. which is right??

Badbaud · « **Reply #14 on:** March 18, 2018, 06:50:03 PM »

The 24VAC is regulated to provide DC voltage for the reels.

alrolon800 · « **Reply #15 on:** March 18, 2018, 07:46:38 PM »

is the 24vac measured from pin 1 to pin 5 and or pin 6 or are those voltages 12 and 13 vac
c

Badbaud · « **Reply #16 on:** March 18, 2018, 10:36:27 PM »

See the attached schematic.
The 24VAC voltage is supplied by the large transformer on the floor of the machine.
That is the primary voltage for the on tray transformer.
The 24VAC voltage is stepped down by the on tray transformer and filtered to provide the DC voltages for Vcc (5V) and Vbb, a isolated DC voltage for systems off the board like the display and the door optic plus input signals from the switches and such.
All of these input signals are opto isolated to prevent static voltage from getting into Vcc and keeping the computer chip and related electronics safe from outside electrical noise.
In engineering terms It is called the "dirty DC voltage".
The 24 VAC primary is also filtered and used to provide the reel motors with a two step voltage via a electronic switch using the large transistor near the filter capacitors.
First full 24VDC voltage is applied to get the motor(s) started then that voltage is stepped down when the motors reach their rotational motion to keep them spinning.

alrolon800 · « **Reply #17 on:** March 19, 2018, 03:18:34 PM »

thanks for the schematic BadBaud. just got another board and it started right up. started swapping out chips and so far all works. gonna finish swapping out all removable ic's and then swap out that 5 volt regulator. gonna put both boards on the bench and comparison check all components in the power supply till I find whats bad. then I will have two working boards. still have a few things to clean up. door optics check good but have a quick flashing yellow candle. BV takes dollar real slow like um, um, um, um, and then spits it out quickly. coin comparator green led is not on and gonna check those out so wife can play. will keep you posted.

Amechanic · « **Reply #18 on:** March 19, 2018, 03:37:09 PM »

The coin comparitor led light does not light up with the door open.

Badbaud · « **Reply #19 on:** March 19, 2018, 04:53:02 PM »

You may need a set denomination chip to get the bill validator to work.
Is it a DBV200 or 145?

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Author Topic: help with igt s+ erratic behavior (Read 3726 times)