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Watkins Copicat grounding

Discussion in 'Electronic Repair Modifications DIY' started by Viceroy is a cat, Jun 2, 2014.

  1. Viceroy is a cat

    Viceroy is a cat Active Member

    Hello everyone,

    I just bought a Copicat ic300 and it has a 2 core mains wire which means it's not grounded. I've had a look around the web but can't find instruction on how to ground it. Can anyone help? is it just as simple as replacing the 2 core to 3 core and connecting the ground to the case? or is there more to it (ie, inputs need grounding)?

    Thanks in advance.

    Viceroy is a cat
     
  2. Boswell

    Boswell Moderator Distinguished Member

    The Watkins schematic for the original UK version of the Copicat 300 shows an earth connection (E) as well as the line and neutral. The E is connected to chassis. It's possible that the US and/or Canadian versions did not bring out a connection to the E point, but locating it or using the chassis point at the output jack and taking it to mains ground should work OK. I'm assuming in your unit the two mains transformer primaries are wired in parallel to give you a 120V mains input.
     
  3. Viceroy is a cat

    Viceroy is a cat Active Member

    Hello Boswell,

    Yes I think this is an issue though, because although the unit is grounded when connected to an amplifier via the output, nothing stops it from getting charged when not connected? right? or no?
     
  4. Boswell

    Boswell Moderator Distinguished Member

    Correct. The UK versions had 3-wire mains leads (cords). Even at the time those units were on sale, it was not legal in the UK to sell goods that had exposed metal parts (such as a jack socket) powered via a 2-wire mains lead.
     
  5. Viceroy is a cat

    Viceroy is a cat Active Member

    Hey Boswell. So mine is the 2 wire mains lead. So I need to change that to three yes? Which brings me to the original question. Is it simply a matter of changing the 2core wire for 3core and attaching the ground to the chassis?
     
  6. Boswell

    Boswell Moderator Distinguished Member

    I used to have one of those units, and I know it had a 3-core mains lead on it. Where exactly the earth was attached at the equipment end I don't remember. If you open the unit up, you should see 3 terminal points with (presumably) the existing lead attached to 2 of them. It's a good guess that you would connect the earth wire to the third, but it would be worth checking with a continuity tester that the third terminal is indeed connected to the sleeve ground on the jack input and output sockets.
     
  7. paulears

    paulears Well-Known Member

    As the unit has the chassis connected to the output socket ground, then what is your purpose in grounding it via the power cord? If you are looking for an electrical safety ground, then it's fine, but you can also be introducing the possibility of a ground loop, as you will have multiple ground paths. Before you replace the cable, why not simply test it by adding a ground and connecting to a loop of wire slid over the jack so when you stick it in, it makes contact? Any ground loops will reveal themselves and save you wasting time putting in a new cable. What do you mean by 'getting charged'? Nothing is getting charged. I wonder if you're concerned about static charge build up? This will not happen because the output socket will be a ground path anyway.

    You know it's really quite difficult for a Brit (I wonder if Boswell has the same problem) to keep swapping words - like ground, for earth, and cord for lead.
     
  8. DonnyThompson

    DonnyThompson Distinguished Member


    ...and "pissed" for drunk instead of angry. And... I've had it up to here ( insert "up to here" emoticon) with you guys adding the letter U into words like color, labor, etc.

    Oh...and chips instead of fries, crisps instead of chips... :confused:

    The search for civilization continues... :p

    Okay. That's it. I quit. ;)
     
  9. paulears

    paulears Well-Known Member

    We've even got a national advert featuring a used car lot salesman - talking about aluminum rather than aluminium!
     
  10. DonnyThompson

    DonnyThompson Distinguished Member

    LOL. Well it's about damned time. Does he have trouble pronouncing it? LOL ;)
     
  11. Viceroy is a cat

    Viceroy is a cat Active Member

    Just to let you all know, unit is now grounded, i even built a new case for it and it sound fantastic!
     

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