How to wire a 2 core plug for '60s Revox Tape Machine? Help!

[Farringdon]

Hi,

I need to wire the plug for a Revox G36 tape machine from 1967. It has a 2 core cable (all black) and a 3 pin plug. I guess there is no earth cable here, but how do I know which wire is LIVE and which is NEUTRAL?

Of the two attached black cables, one of them apears to have a string in it and the other one doesn't. But I'm not sure if this is just coincidence.

Thanks in advance for your help!

Lis

 

[flameport]

Open the casing and see which wire goes to the fuse - that will be the live.

Obviously there may be other electrical issues with a device of that age, and understand that as that is a valve device, there are lethal voltages contained within.

 

[Farringdon]

Is it normal to have no markings at all on the cables? This is a pretty serious tape deck it would be hard to open it up without much expertise.

My friend reckons as they're both black it doesn't matter which is live and which is neutral, apparently it's normal back in the day. But I don't really trust him...

 

[RF Lighting]

Are you sure it's designed to run directly on mains?

Two blacks often indicates it should be connected to a transformer.

 

[Farringdon]

Yes it's a high end consumer or semi-pro reel to reel recorder.

http://www.reeltoreel.de/worldwide/G36.htm

What it looks like opened up (which we're too scared to do):

http://www.youtube.com/watch?v=xl-1lP0wJzg

 

[danechip]

http://www.johnmcculloch.net/docs/g36Manual.pdf

A service manual if it helps

 

[Farringdon]

Thanks for that. However I think this is more of a basic electronics question. The plug was taken apart prior to transport and now we need to rewire the plug.

 

[ban-all-sheds]

RTFM


Nobody here has magic psychic powers which will let them see inside your machine, so nobody here can tell you which core goes where.

And yes - you will have to open it up.

 

[danechip]

Uhm, from the diagrams, you will know if it has a transformer, rectifier etc in the unit or not. Where did the unit come from? Can you ask the supplier what plug was fitted?

I will look through that pdf on a bigger screen tomorrow and advise if i can, but being the age it is would really want properly looking at it rather thann just bang a plug on it and hope for the best.

Dan.

 

[ban-all-sheds]

The manual is legible enough on a laptop screen to show where the incoming power lead connects, and therefore which should be live.

 

[danechip]

Ok, from what i can see on this diagram, it's double pole switch and also has voltage selection. 120 Watts to run it, Either way round L+N and a 3A fuse in your plug.

Edit, BUT 240 VOLTS ON THE SELECTION, JUST INCASE YOU MISREAD !!

Check the manual anyway to see it your model even remotely looks like yours. Good luck !!

 

[ban-all-sheds]

Either way round L+N

I don't think so.....

 

[MrTinker]

Looking at the circuit diagram, either way round will make it work just as well, BUT there is an internal fuse and this SHOULD be connected to the live. So take the cover off and have a look. Don't worry your not going to break it taking the cover off well not unless you use a big hammer to take the cover off

 

[DetlefSchmitz]

This is something of a British affectation. In most of the target markets for this recorder, there would not have been any way to guarantee which way round to connect the mains conductors. The only time this becomes less safe is if the internal fuse blows, and you then decide to open up and work on the equipment without unplugging it.

I say put the plug on either way, as it would have been before anyway.

 

[Paul_C]

In most of the target markets for this recorder, there would not have been any way to guarantee which way round to connect the mains conductors.

Precisely. It's no different in principle than some of the twisted-twin flex which was common on British devices of the era and which also provided no immediate identification of the two conductors. It will work perfectly well whichever way round it's connected. The fuse on the transformer primary is for overload protection, so it doesn't matter which side of the incoming supply it ends up in. With a BS1363 plug you'll have an additional fuse in the "proper" side of the supply anyway.

And aside from the widespread use of reversible plugs, in quite a few areas of the Continent 220V supplies were provided as two phases from a 127/220V three-phase system, so both sides of the feed to the tape recorder would always be live anyway.