Having a problem with my Philco 37-630 in that the volumn level comes in low. I aligned the radio and this helped a little. However its only, when I touch the grid cap of the 6A8G tube ( Det/Osc)that the volumn level/reception gets very loud . This happens on both bands (Broadcast abd Short Wave) so I don't think the problem is with the coils. I also replaced all caps in the set so this would eliminate bad capacitors. Also replaced the tube(6A8G) with another. But no success. Any ideas??
Thanks
John,
I haven't seen the schematic for this radio. You didn't mention if the radio had provision for an external antenna. There may be a screw terminal strip on possibly the rear of the radio chassis with A and G marked. If it does, then an external longwire antenna around 20 or so feet in length may help connected to the A screw.
Radiodoc
::Hi: The philco does have 4 screws on the back for various antenna hook up combinattions . I did have a 2 foot long lamp chord wire on terminal number 1.
However when I was aligning the set with a signal generator following the Philco alignment data sheet,I placed the input clip on that number 1 terminal and the negative to clip number 3 as satted in the Philco alignment pages for that set. The set still behaved the same way in that the volumn/tone jumped much higher when the grid cap was touched.
Also in using a direct connection to the set with a signal generator would that eliminate the possibility of having a too short antenna wire issue? Since the set is getting its signal/tone from a direct feed.
Thanks!
John,
Is this a console radio. You stated it had 4 terminals on the rear. Does this radio if a console have a loop antenna in the cabinet. Some years ago, I acquired a Philco 41-280 and I had a terrible time trying to do the frontend alignment. I had one adjustment that would not at all tune and the reception wasn't very good. I finally woke up and discovered that a loop antenna had to be connected to three of the four terminals. The fourth terminal was for an external speaker. After finally locating a loop and connecting it, alignment worked like it was supposed to. Going directly into the antenna input should eliminate most of any interference because of the loading of the generator.
Radiodoc
Hi:
The radio 37-630 is a table model. I read over the Phillco radio data instructions covering the antenna connections in the back of the chassis. Terminal 1 was the one used for the external wire antenna with terminals 2 and 3 linked together with the jumper.
This set is not designed for easy fixing when it comes to the coils or bandswitch repair and I think one of Philco's less sensible designs. The idea of dividing the circuits into 3 units made sense but making chassis so small in height really left no consideration for servicemen who had to fix it backthen. Thanks
John,
Another thought. Have you replaced any caps in this set. I can't find a schematic for this radio but you may want to check out the AVC circuit. This circuit will probably consist of a high value resistor (2.2meg) coming off the last IF transformer lead that goes to the volume control. On the other side of this resistor will probably be a .05MFD cap to chassis/ground. That cap cannot have any leakage or the AVC circuit will not work right and the IFs gain will not be correct. There may be other resistors and caps to ground past the hi-value resistor. The AVC circuit will probably branch off to the grids of the other IF tubes and the RF amp if there is one.
Radiodoc
If the 37-630 is at all like the 620 (I am in the peanut gallery, and don't have access to the schematic for the 630), it has no 'built in' antenna. It must be connected to a long wire antenna for good results. Also, if you are using a doublet, the jumper should be connected from 3 to 4. However, if you're using an unbalanced long wire, the jumper should go from 3 to 2. If you use a doublet, connect each half to 1 and 2. A doublet will bring you wonderfully static free reception. To make a doublet, take about 25 to 50 feet of wire, whatever will fit in your back yard, and split in the middle with a porcelain insulator. Insulate the ends well, too. You can use insulated wire if you like, if the wire is going to brush against objects. At about 3 feet from each side of the middle, connect a 4 to 5 foot wire. Bring these two wires down to a twin lead-in. Use 100 feet of flat twin lead television antenna cable (the old 300 ohm stuff....can be found at Radio Shack). Use the full 100 feet and don't shorten it. Connect the two wires at the other end to terminals 1 and 2 on your radio. You may secure better static free results with the jumper not connected to anything. If you use a doublet, try it both with the jumper connected between 3 and 4, and without it connected.
The nice thing about the flat twin lead is that it'll fit under your window easily.
Thomas
John: The following receiver trouble and their remedies come from an old book I have.It states that the following problem which is typical of a Philco 37-620 is also an identical problem with the Philco 37-630. I'm quoting exactly what it says:
"If volume level falls off sharply accompanied by resonance hiss, by connecting the aerial to the control grid of the 6A8 or 6L7 (whichever tube may be employed as the 1st detector),or placing a finger upon the control-grid, volume level becomes nearly normal and any resonance hiss clears up to a great extent. This procedure indicates the trouble to lie within the r-f stage. However a volt-meter will not point to the difficulty, which is a snapped lead from the stator lug of the r-f section of the gang condenser to a lug on the wave-band switch, at the wave band switch lug."
Andy