ColecoVision Internal Power Supply

[ikrananka]

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).

[Silent Jack]

Those were great consoles.  We had two growing up.  Where on earth would you find one these days?

[ikrananka]

Those were great consoles.  We had two growing up.  Where on earth would you find one these days?

eBay's a great source, also Kijiji can be quite successful to pick one up locally.

If you're keen then also check out the most active ColecoVision forums over at http://www.atariage.com/forums/forum/115-colecovision-adam/.  There is also an active homebrew scene with some fantastic games being produced, e.g. http://www.opcodegames.com/ and http://www.colecovision.dk/collectorvision.htm.

[Silent Jack]

I have an old emulator archived with around 80 games.  My folks still have the original systems, but they need various repairs.  The one even had an Atari expansion you could plug into the side to play Atari games.

[Hero999]

It depends, if the eath is on the mains site, you should connect it but if it's just the DC common rail, it doesn't matter.

[ikrananka]

It depends, if the eath is on the mains site, you should connect it but if it's just the DC common rail, it doesn't matter.

Is there an easy way to tell or do I need to try and follow the traces?

[Hero999]

Yes, if it's a mains earth the connection will be on the mains side.

Why not simply look at the datasheet or ask the manufacturer if it's not clear to you?

[ikrananka]

Yes, if it's a mains earth the connection will be on the mains side.

Why not simply look at the datasheet or ask the manufacturer if it's not clear to you?

The datasheet makes absolutely no reference to a ground connection.  I emailed the manufacturer weeks ago but received no reply.  I alos spoke to Mouser tech support - not much use either to be honest as the tech just looked at the datasheet and had no other info.