Collaro RC457 record deck from 1958

I always thought the operation of those was knda funky. The way it detects disk size for example. I don't remember if those were the ones that could a ctually auto select the speed as well, but that's neither here nor there.

We saw Collaros in Magnavox console stereos over here. Into the 1970s they had a trimmed down version with a lighter arm. I am pretty sure those did N OT auto select the speed, and I can't remember where I saw that, but it is rare as nen's teeth.

With these rim drive turntables you don't have to add any rubber coating to any metal. There were people in the US who would rerubber these idler tire s actually. One thing about those tires - the size is not critical to speed . Of course they must be within spec enough for the mechanism to work, but the diameters that matter are the insside of the drivien surface of the pla tter and the motor shaft. The only issue is making sure it engages and dise ngages.

Have fun with it.

I think the record size determination is the little metal "semaphore" arm that sticks inwards from the large post. If it leaves the arm untouched then a single, if 12 inch then it moves the arm down and that cross-links to the tonearm-drop mechanism, 78s don't know , perhaps manual for them, 1950s anyway not 1930s. I don't think there is a cross-link to the speed change system. The original rim surface of the drive disc is too rough for driving the platter, I would have thought, perhaps originally it was as smooth as the PTO one but breaks up in use like cassette tape pinch wheels, or tyred of course.

The info here

is very similar model.

I've had some luck on occasion stretching an O ring onto the rim. As Jurb h as already said size doesn't matter, (although I might add at least not in this case). You might have to go to an auto parts store, a plumbing supply or a transmission rebuilder for such a ring though, and it may have to be g lued in place if the rim has no shoulders. Lenny

The pulley here is just a 2mm thick hard rubberdisc, so the only way of tyring it , is to pre-stretch , over night, some inner tube and then fit it over the edge, draped over each face, holds quite well but glued for reassurance

A B&O I dealt with sometime weighed the record to set what size it was. This one , going by the vintage audio thread ref'd elesewhere here. The bod wiht the jammed and broken main bearing. Just the sort of damage I could expect from a short countersunk 6BA screw working loose and getting jammed in that central area. So hippocratic fashion and do no harm. Not knowing what went in there and its function. As the tapped hole does connect through to the axis, I'll fill with hotmelt glue as a bung and pack grease in the gap space.

I don't know how many times I've picked up this deck, but it must have been always the same way round. Until this morning and on the other side of the main stem is an exactly similar countersunk hole with a small screw in it. Must be for fixing 2 cylindrical parts together. Other than checking for tightness I don't think I'll fix a screw in the other side , as there is perhaps a liklihood of them loosening over time, unless it turns out that it gives the mechanism a malfunction with only 1 fixing

All that mechanical rat's nest is now working, except for 16RPM and have not tried stacking records (I've only one single for test purposes) but the hold and drop mechanism works for one and clamping arm, last record height sensing, for final eject works. Now to fit 3 core earthed cable, someone previously had connected record deck metalwork to mains neutral, not just the isolated lowside (theoretically if house wiring is standard) amp chasis

Deck run off the mains at near enough correct speed (shaded pole type) counting revs in a minute. Try with the amp and very sluggish. Looks as though the deck could never have worked as is. The schematic shows 160V ,.1A motor used as a dropper for 2x 40V valve heaters and 3.5V pilot bulb for 240V mains. Perhaps someone changed the motor back in history to the present 240V, 14W one and gave up. The only way to run this is add a dropper for the heaters and rewire the motor direct off 240V

Small output impedance matching transformer for 7W output, DC resistance of primaries measuring 746 and 350 ohm , inductance 1.95uH/2.1uH, would that amount of winding resistance disparity be expected?

Must be normal. Distortion, partial half-wave , due to a failing coupling cap, replaced the TCC Plastiseal rod caps that look like waxed caps and all ok. Removed the speaker to have a look at the Calibri Electrostatic HT64 speaker, working order to above 12KHz, just curious ,not seen one before