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Philco 49-607 inop - Printable Version

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Philco 49-607 inop - Tennangler - 12-11-2024

Hi, I am new to the forum and excited to increase my knowledge of antique radios.
I was given this inop Philco 49-607 and would like to know where to start my troubleshooting. I powered it on through a dim bulb tester. The bulb did not light. Tube 117z3 glowed bright for a moment and went out. I did see light from other tubes and got no sound even at full volume. The label shows code 121.
I am hoping to get some guidance as I am limited on my knowledge of tube gear.
Thanks 
James

RE: Philco 49-607 inop - GarySP - 12-11-2024

Welcome to the Phorum, James! According to the information available in our Philco Radio Gallery and Philco Radio Library, your 49-607 is probably a 48-360 chassis in a 'refreshed' cabinet. Plenty of information is available in those sites located at the bottom of this page. Photographs are always helpful. It sounds like the 117z3 tube is now toast. I would recommend replacing all paper and electrolytic caps, and any out-of-tolerance resistors. I am sure others who have worked on these will help out with more information. Take care and BE HEALTHY! Gary

RE: Philco 49-607 inop - morzh - 12-11-2024

OK, first things first: As Gary has said, do not power up, not with dim bulb, or anything else, until all the tubular/backelite/electrolytic (with the exception of the mica) capacitors are replaced, and the tubes tested.
Then you will tend to other things.

RE: Philco 49-607 inop - Tennangler - 12-11-2024

    I found this troubleshooting guide and got 117vac at test point A and 0 at tp C. I got 0 at tp D which indicated a bad tube or switches. I cleaned the switches and the 117z3 tube socket. Still no voltage. As I said earlier, the tube lights bright when I first turn it on and then dims. This has happened several times. I have to let it be off for over an hour for it to light when I turn it on. 
I will get the tube checked or get another. 
Is it likely I have fried the tube at ignition? 
James

RE: Philco 49-607 inop - MrFixr55 - 12-11-2024

Hi Tennangler,

Welcome to the Philco Phorum!  Lots of phine phriendly phlks phull of Philco phacts. (See a pattern here?)
Was the negative lead on test point B for all the tests? If it was ion the chassis instead, you woll get verylow readings ans this is a "warm" chassis (isolated by a cap and high resistance resistor), not a "hot "chassis (one side of AC line connected directly to the chassis).

Like Gary and Morzh said, consider replacing all capacitors, especially the electrolytics, before powering up. The electrolytic and paper caps are known to short or open. There is no need to replace the mica caps in the audio section unless you find them to be bad.

Attached below is the complete schematic for Model 49-105, similar to your 49-107.
.pdf Philco 49-605.pdf Size: 2.38 MB  Downloads: 1


Attached below is a blow up of the power supply.
   

It is common for certain tubes to glow bright and dim, and the 117Z3 is no exception.  However, the tube should glow an orange to almost yellow glow, and the cathode tube should glow wen te tube settles down. It is possible that the tube get intermittent, but this is not common. Most tubes either work or fail as far as the heater goes. You can CAREFULLY check for 120V AC between pins 23 and 4 when the issue occurs. If AC is there, then the tube is bad or the socket connection is bad. If not there, then investigate S100 and S101

It is important that S100 and S101be clean or you will fail the tests in the guide that you got from the Rider manual for this set.  Spray switches with Caig DeOxIt contact cleaner, but use Caig DeOxIt fader lube for the volume control.  Exercise the power switch (S101) by turning on and off. Exercise the AC Battery Switch (S100) by inserting the plug into the hole on the chassis designed for it.  This switches the radio to battery.

Note that the filaments of the tubes other than the rectifier are all in series and run off a 7.5V battery if the unit as on battery power.  Some folks would put a 9V Zener diode across the filament supply.  The most convenient spot to do so is C100D  

It is important to get the wiring right with this power supply, especially the cap values and the candohm, R100. Failure to do so could cause the tubes other than the rectifier to burn out.  They are all pretty common except the Audio Output Tube, 3LF4.  I think that these are rather rare!  Note that the tubes other than the rectifier don't really light up, even in a very dark room.