I am in the process of building an internal power supply mod for the 1980s ColecoVision games console. This is based on an open frame power supply with triple output (http://www.cincon.com/data/products/cfm2_1/CFM40D_T.pdf). I have built and tested a prototype unit and it works great, is much lighter than the standard external CV power brick and has the advantage of only requiring a standard household power cord to connect the CV to the mains supply. However, I am not an electrical engineer and have concerns over safety and grounding but do not know the answers. So, looking for some advice on the following (hope someone can help):
1.In one corner of the power supply PCB there is an earth/ground symbol marked with a trace running from a capacitor to a circular trace running around the adjacent mounting hole. I believe that I should have this connected to ground - is this correct?
2.One of the other mounting holes also has a circular trace running around it (connected to another capacitor) but does not have an earth/ground symbol next to it. There is NO electrical connection between the two circular traces - should this second trace also be grounded?
3.The other two mounting holes do NOT have traces around them. Nevertheless, I plan on mounting the power supply using metal screws and metal standoffs. The bottom screws will be outside of the CV case, can be touched, and so in theory there could be an internal short to these screws - do you agree therefore that all four screws/standoffs be grounded?
4.Do I need to provide some kind of physical shield in case a user pokes a metal objects through the CV air vents thus preventing them from touching the power supply? Or is this overkill? I can see quite a number of consumer electronic items that I have that I could easily poke something inside and touch the internals (not that I ever would mind you).
1.In one corner of the power supply PCB there is an earth/ground symbol marked with a trace running from a capacitor to a circular trace running around the adjacent mounting hole. I believe that I should have this connected to ground - is this correct?
2.One of the other mounting holes also has a circular trace running around it (connected to another capacitor) but does not have an earth/ground symbol next to it. There is NO electrical connection between the two circular traces - should this second trace also be grounded?
3.The other two mounting holes do NOT have traces around them. Nevertheless, I plan on mounting the power supply using metal screws and metal standoffs. The bottom screws will be outside of the CV case, can be touched, and so in theory there could be an internal short to these screws - do you agree therefore that all four screws/standoffs be grounded?
4.Do I need to provide some kind of physical shield in case a user pokes a metal objects through the CV air vents thus preventing them from touching the power supply? Or is this overkill? I can see quite a number of consumer electronic items that I have that I could easily poke something inside and touch the internals (not that I ever would mind you).