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37-650 Simple Questions - Printable Version

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37-650 Simple Questions - Robbie Roberts - 12-22-2005

Ok, here's a couple simple ones:

First, regarding the dial lamp- should the "reflector" cup the bulb sits in be shiny inside, or black painted, as mine is now?

Second, what does the "Shadow Meter" actually do, and how does it do this? It appears to be an empty tube with a coil around it that a lamp shines through.

Thanks!
Scott

PS-
Ron- Bought your book from Radio Daze today... Said they were getting low on stock, and I felt I better oughta... Can't wait to see/read it, so I can be a more fully informed Philcophile. S.

- Ron Ramirez - 12-22-2005

Hi Scott

Every 1937 Philco dial lamp reflector I've ever seen had been painted black. It would seem that if they had been nickel plated on the inside, that they would reflect light toward the front better?

Read this article at Chuck's website about shadow meters.
http://www.philcorepairbench.com/tips/svctip01.htm

Update on 37-650 Project - Robbie Roberts - 01-03-2006

Well, the last cap has been recapped, all the resistors(except 1) have been replaced, and the wiring is now up to snuff... I have the whole thing together again- sub-chassis is happily reassembled and back in place, everything!

I even learned how to repair a tuning capacitor rack: I found the foreward most cap set (fixed plates) had a broken phenolic mounting tab(actually both) so I had to remove it and make new ones. Worked out well- especially once I discovered the mounting tabs were soldered on! And, of course, I figured out how to set the air gap... Lots of fun, but looks right.

Now to start her up. Since I don't have a variac(that I'm aware of, but just might- in storage) I am going to try the lightbulb in series concept to reduce initial voltage. I do need to know(and this may sound stupid) when I test voltages at the tube sockets, are the tubes in place, and I check from below, or just pull a tube, check the pin sockets for voltage, and replace the tube? And if it is pull the tube, is it all right to pull a tube with power appiled? I know my Z-word TOs can blow their tubes if you remove with power applied...

Suggestions welcome!
Thanks!

Robbie

PS- Does anyone know the correct sequence for the band indicator pivot? Is it gear-shield & plate-felt washer-dial hub, or gear-felt washer-shield and plate-dial hub? I can't seem to recall... R.

- Terry Burns - 01-03-2006

Hi Robbie,

Make your voltage checks with the tubes in their sockets. If one or more tubes are removed it will cause more B+ to your remaining tubes. Keep an eye on the rectifer tube. If the plate starts to turn red there is something wrong in the radio and drawing to much current. Voltages may be higher on your meter compared to what the schematic says. Voltage input for that radio is 115V? Line voltage today is 125v. Also a DMM will load down the circuit less.

Good luck
Terry

DMM? - Robbie Roberts - 01-03-2006

Terry- A "DMM"?
I'm not yet familiar with the term Icon_smile
Thanks for the reply!

Scott

- Chuck Schwark - 01-03-2006

Digital Multi-Meter Scott.

- Robbie Roberts - 01-03-2006

Ahhhh...lol... Thanks!

Scott

ITS ALIVE!!! - Robbie Roberts - 01-04-2006

It Is Alive! Although at low power for initial testing, the wonderful words "The big talker 1210" came across quiet but clear on the 37-650 speaker minutes ago... The light bulb (75W) power reducer is very dim, all tubes are warming... Now to give her a few minutes, and I will try full power...

Robbie

Seems OK- restoration report - Robbie Roberts - 01-04-2006

Well, I've had her up and running for a couple hours now: while she is reasonably volumned, I am wondering if she may be a little quiet- and if so, how would I go about rectifying this? I found(before I added a rough wire antenna along the wall) that if I touched the top terminal of the 6A8G Det-Osc tube, the volume would pick up. With regard to the tubes, I replaced one of the two 6F6G tubes- and the other is a 6F6GT. And I seem to recall it(the GT) being a touch weak. Could this be the cause of lower than optimum volume?

All switches seem ok- I get nice tone change with the tone control.

AM and the first SW band seem fine- couldn't find anything on the top SW band, but I will try later in the day. With the antenna(just a long wire attached to the 1 terminal, and running between 6 and 8 feet high, about 30' long) in place, I get all sorts of stations- I found a Buffalo, NY station about 1520, which plays old stuff. I am outside of Philadelphia, so I know I'm catching a good signal.

I am pretty sure my Shadow Meter is not operating properly- I read through the information on Chuck's site, but I see no part which would operate as described in the way of a mgnetically induced flap- I am of the opinion it has been removed from the unit for some reason. All I get for display from it is a nice bar of light above the dial.

The dial lamp seems to be operating nicely- I like the way it back glows and has the well defined indicator line.

Anyway, any suggestions to how to inprove performance greatly appreciated.(All caps, bakelites, resistors, most wires, replaced or rebuilt)

Thanks!
Scott