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Philco Beam of Light Photo Cell
#2

It's been a while since I placed this post. Although I didn't receive any feedback here, I did hear from a fellow over at the ARF site. He suggested that I look for a "Rowe" Dollar Bill Acceptor. He had worked in the Jukebox industry for a number of years and found that the units being put out by the Rowe company used three small photo cells to read the dollar bills as they were inserted into the machine. He had rebuilt a BOL unit some years ago using one of those photo cells and found the results to be very acceptable.

I started searching for an old Rowe Acceptor and found one on Ebay for $10.00. It was quite heavy and so the shipping was about $12.00, but it would be worth it if I could get a good photovoltaic cell. When the Acceptor arrived I have to admit I was quite skeptical about the whole thing and figured I'd been sent on another wild goose chase. I was able to "harvest" three of the cells from the Acceptor.

Here's what the new photo cell looks like:[Image: http://i642.photobucket.com/albums/uu143...C_0498.jpg]

It's attached to a small triangular PCB and it looks like the cell is sealed inside of a TO-39 transistor casing. It has two legs extending out the bottom just like a transistor.

[Image: http://i642.photobucket.com/albums/uu143...C_0501.jpg]
A close up of the cell shows that it has two leads coming from the cell to the legs extending out the back. It is not removeable from this round metal casing.

[Image: http://i642.photobucket.com/albums/uu143...C_0504.jpg]
Just for comparison....here's the original Philco installed photo cell.......

But...as luck would have it, the new round photovoltaic fits quite well into the same spot where the original cell sat. It only took a minor amount of filing to fit it into place. Here's a picture of the "new" cell mounted in the casing of the original photocell and placed back into the headshell assembly on the end of the phonograph arm. [Image: http://i642.photobucket.com/albums/uu143...C_0522.jpg]

I had already replaced the rubber bushings holding the needle/mirror assembly in place. I also replaced the rubber mounting material on the rear of the tone arm and the foam holding the special BOL lamp in it's holder.

The only thing left to do was to give it a try. Here's the headshell glowing as the bulb sends a beam of light by way of the mirror to the new photovoltaic cell.
[Image: http://i642.photobucket.com/albums/uu143...C_0532.jpg]

I was totally unprepared for what I heard when the record began to play. The sound produced by this new and apparently better photo cell is nothing short of astonishing!!! I'd always heard that these BOL systems tended to sound boomy, bassy, and not have too much in the top end, but this BOL system has more highs than you could ever want with a nice tight, healthy sounding bass. I think that this has to rank among the best sounding 78rpm playback systems that I have ever heard.

Philco went to great lengths to proclaim the importance of the angle of the needle to the surface of the record. If you take a look at this picture, you'll notice that the needle has a slight angle to it. It's supposed to have an angle of approximately 13 degrees when viewed from a side profile. The needle/mirror assembly shown is a NOS piece with the appropriate angle.
[Image: http://i642.photobucket.com/albums/uu143...C_0506.jpg]

Another interesting fact is that this needle only tracks at about 1 1/4 oz. By the standards of the day that was a pretty darned light tracking force considering most cartridges at that time would track at 5 grams and up. And of coarse the BOL had a permanent jewel for a needle that was supposed to be good for about 800 hours of playtime.

Here's a photo of the turntable and another of the entire Philco 41-616 Console.
[Image: http://i642.photobucket.com/albums/uu143...C_0539.jpg]


As you can see this Philco 41-616 Console has the BOL Deluxe Changer, Mystery Control, and Home Recording Unit. The Remote Control Box and the Home Recording Microphone are sitting on top of the unit.
[Image: http://i642.photobucket.com/albums/uu143...onsole.jpg]


All in all this is an incredible system when it works properly. The biggest hurdle for me was finding that all illusive photovoltaic, but with that obstacle behind me.....all is well.

Funny thing though....every time it finishes playing a record it trys to give me $.50 change?? Icon_smile
Bob


Messages In This Thread
Philco Beam of Light Photo Cell - by Ampico-kid - 04-09-2009, 03:34 PM
Re: Philco Beam of Light Photo Cell - by Ampico-kid - 05-27-2009, 10:40 PM



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