This might sound all too familiar. You have a machine that’s been working very well for perhaps three seasons or more. The machine’s main logic board runs fine first thing in the morning sometimes even all day without any problems at all. Every now and again it just seems to freeze up, mainly in the afternoon. You switch it off for a few  hours, trn it back on in the evening and it works fine for the rest of the night.

It’s a good income machine so you decide to send the board away for repair, or at least find out what’s wrong and decide what to do. The service department report the game’s been running for three days, 24 hours a day and they can find no problem. The service company returns the game board and suggest you check the power supply, this often being the most common cause of intermittent freezing up.
      You check the power supply voltages at the top end of the logic board at a point furthest away from the power to PCB connector and these are all fine. The game runs for a day and then cuts out. No matter where you are in the world and it you have no other explanation, you can do what we do in the UK and blame it on the weather.

      The situation might just be this. The machine is switched on first thing in the morning when the temperature both inside and outside the site location is fairly cool. As the day goes on, the machine together with others in the same site location generates heat. The temperature inside the building at mid morning and last thing in the evening could be just about around the same.
      However, at certain times of the year such as summer, the outside temperature increases in the afternoon to its peak, and gradually falls towards the late evening. This outside temperature combined with the heat generated inside the building may cause the logic board to reach and then exceed its maximum working temperature, so the game board switches off.
      Cool mornings are no problem. Hot afternoons see the machines freeze, so you switch the machine off. Cool evenings see you try the machine again and it works again. The heat inside and eventually outside is the problem not the PCB or power supply. So what can you do to resolve the problem?

The problem is caused by a reaction to extreme heat. You see, the machine and particularly the game board have minimum and maximum working temperatures, as set out in the operators handbook. Logic boards and sometimes whole machines have thermal cut offs to protect them against damage due to excessive power, heat or, worst of all, fire.
      Keeping the machine cool is the answer to the problem. Most machines will have cooling fans and heat convection cut outs in the bottom or sides and top of the machine’s cabinet. In addition the logic board may have a mini 12v extractor fan mounted directly on top of the main processor device.
      If the machine is a video game it is common to find the logic boards in a thin sheet metal alloy case. This too may have extractor fans built into the top or at one end of the assembly unit. When the service department tested the board it’s a fair bet to assume this was being done on an open bench or test rack and the board had good ventilation all around it. Put this same board in a tin can, then in the bottom of a wooden box, the cabinet, then in the corner of an arcade games where the air has very poor circulation, you can see a different set of circumstances forming.

Ventilation check list

Rule number one –never be tempted to leave a back door or service inspection cover off any machine in an effort to create or improve cool air circulation. Young players are inquisitive by nature. An open door is an open invitation and could be disastrous. Start with the processor cooling fan. Ensure it is running freely and continuously. Using a soft paint brush, very gently brush and vacuum any dirt and dust from all over the logic board and components, particularly the fan itself. Now move on to the metal case if applicable. Vacuum and brush all vent holes and slots, including the circulation fan if one is fitted.

Next is to clean the inside of the cabinet itself and stop the build up of more dust. Start at the top and work down. Disturbed dust floats down, so don’t be tempted to start at the biggest build up of dust which will always be at the bottom of the machine. Heating is one thing, ventilation is another. In order to release heat from an amusement online poker machine it’s not simply a case of heat rises, so holes at the top are all that matters. You must have convectional flow, which means that cool air enters the bottom of the machine at the lowest point possible, picks up the heat in the machine and then ventilates out of the top at the highest point possible.
      Now I’ll tell you what to do if the machine is as clean as the day it was made but the problem persists. Try increasing the number and size of the ventilation holes bottom and top, but always remember to ensure you put mesh or grills on the inside of all the holes in the cabinet. The next and perhaps final step, prior to re-engineering the cabinet, is to move the machine to a central location within the building, not in a ‘dead air’ corner where very little air circulates