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Otari CTM-10 Cart machine tech info / manual

S

Studio1

I have a CTM-10 cart machine currently set up for 110 volt operation. I need to change it to 230 volts.

I see the transformer has two spare wires on the primary - blue and grey. The ends are heatshrinked over.

Does anyone have the service manual for this unit and can tell me what the configuration should be for 230 volts?

The pair that are hooked onto the mains socket at the moment are white and black.
 
Without seeing this, but as a guideline, the way transformer primaries usually work is:

2 primary coils, for 110 vac you connect both of them in parallel, one across the other, and feed both together;
for 220 vac you connect both coils in series with the voltage going into the first coil then into the second.

Either way the secondary would get about the same output. Also you have to watch your phasing, that is the direction you are feeding the coils, so that one primary coil is working with the other, not against it.

If you can figure this out, you should be able to rewire it from 110 to 220 input. Also try looking for any model numbers on the transformer so you can find a drawing or connection chart from the manufacturer.

Lastly, since the input voltage is twice of what it was, you can usually change the input fuse to half the current for protection, but it will work either way.
 
Thanks for that advice.

What I didn't say is I've already looked at doing that, and I found that the DC resistance of the white and black pair (currently the 110V windings) is about 12 ohms. The resistance of the gray and blue pair is about 6 ohms. I would expect to see about the same as the other winding if they were two 110v windings identical.

I metered between the white and the blue and got around 37 ohms which was the highest reading between any two windings - so figured this was the pair to use. Hooked them up first via a 40 watt lamp in series with the mains (as a 'ballast load'), and it ran perfectly, but the lamp was fairly bright.

I took the lamp out and plugged the machine into my VARIAC and wound it up slowly from 0V - all was good until I got to around 150 volts and the transformer started buzzing.

So it's back to the drawing board and the hope that someone here has the book for this unit so I can get it right and not fry up the machine!

The transformer is in a right sh*t of a position to remove it from, without dismantling the whole machine, so I am loathe to try that at this stage. I did look at the idea however as sometimes they print the connection details of the windings on the outside.
 
All sorted now thanks..

Sat down with the meter and did some more checks. Turns out the BLACK wire is the common on the primary, and BLUE is the 230v tap.

Now I just need to replace the missing drive belt!
 
Alan Fletcher said:
I didn't even know Otari made cart machines... lol.

-A
Click to expand...

Yep... they did :)

R
 
Alan Fletcher said:
Otari makes nice stuff.

My baby is an MX5050-BQ-III open-reel deck that I surmise came from the Tom-Tom Club studios of Tina Weymouth and Chris Frantz, (of Talking Heads fame), in Fairfield, CT. It's a beefed-up 4-Track version of the 5050BII machines you (used to) see in radio studios. It is in excellent condition with recently re-lapped heads. Does 3-1/2, 7-1/2, and 15IPS speeds. Nice decks indeed. I imagine the cart machines are of similar quality...

And no, I was not joking about having cart machines in the studio. Analog rocks! Anyone who doesn't see the digital revolution in broadcasting as a threat both to human skill and creativity and also an excuse to ax jobs, is blind. IMO.

-A
Click to expand...
 
SFM-Ptgal said:
Robert Bass said:
Alan Fletcher said:
I didn't even know Otari made cart machines... lol.

-A
Click to expand...

Yep... they did :)

R
Click to expand...

And from what I've seen here and there they had pretty nice features, hardly seen on the US ones... But I didn't know that they were belt driven ::)
Click to expand...

If you think that's bad, the Otari ARS1000's playback reel decks had belt drive cap's as well. Nothing like hearing a song go dead when the belt broke.

R
 
Alan Fletcher said:
And no, I was not joking about having cart machines in the studio. Analog rocks! Anyone who doesn't see the digital revolution in broadcasting as a threat both to human skill and creativity and also an excuse to ax jobs, is blind. IMO.
Click to expand...

Having worked with both in my career, they each have their pro's and con's. I don't consider digital a threat to human skill and creativity. In fact I think such gear actually improves skills. I like analog and digital equally.

R
 
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