Sigma 300 acting crazy

[Randy0777]

 This is mainly for a refrence for others  . Never had a machine drive me crazy yet,but its REAL close. The machine may play fine for a few hours,then locks up...all displays,lights,etc is on but nothing works. Turn key,push butttons,open door ,etc. Sometimes when I turn it on it will go through the boot process and game loads. 3 sec's after loading the game will start loading again  . Sometimes after it locks up and you just let it sit ( could be 1 min or 1 hour...it changes) it will just start loading again. Sometimes while its locked up the wheels will spin about a inch, than a few sec's do it again. Earlier I started and as soon as it loaded I dropped  10 coins( 45 is max bet) 6 of them showed up and the machine locked up...restarted and the other four then registered. Pulled the board and switched chips to a empty board...same thing. Then put that board in another game and it ran fine for 24 hours. Switched the board on the door and same thing...locks up. Also,some of the times it locks up the speaker will start popping. Checked for pinched cables,cleaned connections. Next step is to change power supply, then cables...1 at a time 

Figures,go to work on it ...and it wont lock up 

[jay]

If it locks up after you get those 3 x 7's (lower picture) that would be indicitive that you have won.....and the machine has gone into hand pay....    This never happens on my machines 

Ok I know I deserve a good  for that.... I would venture to say that you are likely correct in your speculation of a a power supply issue. It could be you are losing one of your voltage lines. Especially the part about mostly remaining up but frozen then reloading.

If its not the power supply It sounds like something is heating up (ie cold solder joint) you lose the voltage, machine dies - cools and the cycle repeats.

Its always good when something breaks as you can find the issue and then fix or replace - these flakey problems drive me nuts too.
Usually the first step is to try and cause the problem to occur, on demand. Or to swap the suspect part and see if the problem moves with it like you have done with your MPU.
Since I have 3 of the same platform I have become highly skilled at the art of swaptronics.

In this case I would consider getting a can of cooling spray and after the machine goes into the mystery mode give it a shot of cooling.

If we think it is one voltage line dropping another thought would be to pull or cut one voltage line at a time to see if you can duplicate the problem.

Good luck .....

[Randy0777]

3 any 7's only pays 250 
I replaced the upper power supply about an hour ago and all seems fine...so far
I'll let it run for a day and reply back on the status

Been 24 hrs and still running without problem . So the power suply was the problem