Hi everyone, Im Bob, new to posting on this site, hope Im in the right place, I recently received a Crosley 51 in bits,every component has been desoldered. Im trying to work out how to ID the tap wires from the fixed coil so I can resolder them back onto the switch. Strangely enough there is another fixed coil piggy backed on to the usual coil as seen in many pics online of Crosley 51s.
I can only guess that this extra coil, which is just one winding as there are only two wires, it must go in series with the other one ??
The tickler I can identify no problem, I have attached photos, maybe someone out there could take a photo of their tapped coil arrangement and post here thanks.
Just retired last nov, 45 years in electronics, military, civil commercial so I know my way around this stuff. Cheers all.

Hi Bob, welcome to the forums!

Schematic and hookup diagram is here:
http://www.nostalgiaair.org/Resources/372/M0003372.htm

I don't see that third coil in pics of other 51s online. You got me stumped.

I have (2) Crosley 51 radios in my collection. They are all constructed exactly as the 1920's schematic indicates.

I would "rebuild" your Crosley 51 exactly as the schematic shows. That is the correct circuit. That extra spider coil, IMO,
has no reason to be there. I highly doubt it was there originally.

Jeff

I see the extra coil as either a loading coil for long-wave or a conversion to make the tuner a three-circuit. Useful in both instances, as a receiver for long wave it would make the set capable of receiving time signals, for what ever purpose, navigation, jeweler/clock/watch repair. As a three circuit tuner it would isolate the the antenna from the effects of loading the regenerative circuit, reduce any regeneration oscillation from reaching the antenna and causing local interference. Despite the coil being so close to the tuned winding.

If the history of the set could be known there may be an explanation. The "extra" spider coil looks like a Crosley product, maybe review of their products available at the time this set was offered, could be found in ads for Crosley at World Radio History.

https://worldradiohistory.com/index.htm

Some radio manufacturers did offer long wave loading coils but these were often external to the set. However, Crosley was into compact, inexpensive designs at this time...

A Jewelers time receiver was, often, more elaborate and costlier that a Crosley 51...

Chas

A loading coil, with a switch to switch it in or out?

As to the original coil connections;
The green sleeve wire goes to the book condenser, outside connection (with the grid leak). Then there are 5 taps on the coil, from the outside to the inside. Holding the panel upside down, looking from the back, the outer-most tap goes to the left terminal. Then they connect in order from outside to inside taps with the inner-most tap connected to the last terminal on the right.

When connected correctly you should get from about 1.6 to 5 ohms, in steps, measured from the grid leak input to ground. On these radios, this is one of the most difficult switches to work correctly; usually when using the radio I just wiggle the do-do out of it until I get some stations, then don't touch it (or even look at it).

Here are some pictures of mine. I have the wood faceplate, but insides are the same.

Thks guys and Technopol for those pics, very helpful, much appreciated. I bought this 51 from a guy in Arizona, he also had a 52, both in bits, my theory is he was going to part them out but changed plans. Anyway I think as was suggested that extra coil doesnt belong and someone did a mod and fitted a loading coil like in the Crosley trirdyn but that coil is bolted to the side wall with a selector switch so Im dunno!
It appears by the way the wires rest or in other words their shape, that extra coil black sleeve wire wants to be on switch contact 5 and the other long wire has a crimp lug like it wants to go to the book cap?
Someone has fitted a push button switch as seen in my pics so maybe was used to switch that extra coil in to circuit, the plot thickens!
I will get it going as per the OEM schematic and then mess around with that extra coil and see if it does work as a LW load coil or if too hard will leave it unconnected. Interesting in that my fixed coil has 4 wires plus that long green sleeved wire from the top of the coil but the Crosley physical pic of the switch wiring shows 5 wires to the switch plus the long green sleeve to the book cap. It does not show the green sleeve wire (top of the coil) also going to the switch as per the circuit schematic. Bit of a bitzer this one. Would be nice to sort it properly but at the end of the day to get it working is the aim regardless.
I received two tube sockets with it lying inside the box, one bakelite socket and the other is a metal unit, these dont appear to be original but the bakelite one has tapped mounting holes for those long spacers but that doesnt matter as I have fitted octal sockets and plan to run 1Q5 tubes for the detector and output stage which will run a speaker via a suitable speaker tranny.
Will keep you posted as to progress.

I have 3 or 4 of these and they are all wired like the drawing. I think the schematic is incorrect at the top. The book condenser connects to the top of the coil, then if you move the first 4 switch connections down one position on the coil, then the schematic matches the drawing.

Thks Jeff, that makes sense, although the crosley wiring diagram shows 5 taps plus the book condensor green wire, the schematic as you said correctly shows 4 taps down the coil from the top green wire, Ive seen lots of schematics over the years full of errors which slip thru.
I have wired it as per schematic, I used the left over tap, 1st or 5th depends which way you look at it, to switch in and out that odd ball coil and see what happens. Still a work in progress, waiting for 12G buss wire to turn up. I dont know what the added switch was for, I replaced it with a 1/4 inch phone jack for a ext speaker, fills up the hole.

Thks everyone for their input, got it working surprisingly easy, plenty of audio to drive a ext speaker, reasonably sensitive on a average aerial length, not restored to original condition as I received it in a disassembled condition so I have modified it to a more useful state, that small 7 pin tube is a 1S5 audio preamp driving a 1Q5GT speaker amp, it is working quite well now, maybe better than factory new.

Good job, dazzler. Some clever mods there.

A question for anyone out there with a Crosley51, the lid on my unit looks like it had some pads on the forward corners where it makes contact with the main wooden cabinet and there is a small hole in each corner. I cant see any reason to drill a hole or put tape or whatever. Also toward the centre of the lid there are 3 little pin holes in a triangular pattern, anyone else seen these in Crosley 50/51 series lids?
Ive looked online at other crosleys but none have these peculiarities. Just mainly curious thats all.

Just another modification in its life, not an OEM for sure. Little left to identify as Crosley in this example, panel, knobs, book condenser. Though I have found them as parts sets as well and pieced them back together. I never cared for the series tuned front end. Designed for a high capacity antenna, a through-back from the Wireless era... Then again, Crosley was aware of the needs of his customers.

Thks Chas, yeah its amazing sometimes what people do in the past modifying things. Must have been a good reason at the time!