[boxjoint]

What happened to your radio is it working ?

[Tom Hamilton]

Hi,

You mentioned the grid cap came off one of your tubes. It can be repaired and it's not too hard. Here is a video by Joernone: http://www.youtube.com/watch?v=O25SxqWmyfw He does an excellent job of radio restoration for beginners and his videos are well worth following. He is currently working on a 1935 Atwater Kent.

Good luck with your Philco. As you're finding out, there's lots of great advice and information at the Philco phorum.

Tom

[morzh]

I repair grid caps only if I know the tube is expensive and is good enough on the tester; what I do is I heat up the cap and simply shake the solder off, so the small hole is exposed. The hole and the wire are usually aligned so I put the cap back until the wire protrudes, and simply melt some solder on. If there is any adhesive that can glue the metal to glass and stand to high temps it can be used to hold the cap, but that's what I don't do. It holds well enough for it not to come off by itself.

[VintageVolts]

It's been a while since I poked around the radio. It was sitting on the corner of the workbench for months.

I tried to get things working, but to no avail. So, I've decided to commit to the project for the long haul. I am going to completely strip the chassis, clean it up, and reassemble the radio part by part. Hopefully I can do so in stages so I can test each stage as I add them.

My biggest problem will be keeping track of everything! It's really a mess under there! I'm not afraid to do the work. I'm just worried about losing my place in the process. I took 40 or 50 closeup pictures of the underside and all around the top side. But still, I can see where that might not be enough as a suitable guide. When I remove a block capacitor, or even one of those mica capacitors, I put a number on the part and the same number on the chassis where I removed it.

Is there anything else I could do to better track this process?

Does Chuck Schwark's repro manual have the point to point wiring diagram, along with the info needed to identify which tabs are which on the coils, etc? In other words, could I rebuild the radio from the ground up with that original manual?

[vinzer]

I have a model 19b and they are know to have open coil ant rf and osc. but they are easy to rewind one was open on mine don't remember witch one it was but I rewound it .
its usual the top winding there's not very many windings just count them as you unwind them and make sure to wind them the same way the old ones were wound if you have bad coil.

[Joeztech]

Jeff;

Just to add a little to Steve's comment about the 80 rectifier tube, most rectifier tubes are on a separate filament winding of the transformer to keep a potential short of heater to cathode from causing a major short in the power supply. If all the tubes in a set had their filaments in a common circuit all of them would be subjected to B+ on their filaments plus their normal AC voltage. Potentially a good number of parts could be fried as a result. There are some more modern rectifier tubes that use 6.3VAC filaments, but even they are supplied with filament voltage from a separate winding of the transformer. Some of the 6.3VAC filament tube designs have a separate heater and cathode, but most of the older 5VAC filament designs have the heater as the active cathode element, so heater and cathode are one and the same in those designs. Some more modern Hi-Fi and stereo tube equipment used solid state rectifiers to create a DC voltage and filtered it with electrolytics and then applied it to the filaments of tubes in the audio preamp circuits. This was done to help eliminate 60Hz hum from the audio. Older radios such as these only use AC on the tube filaments.

Joe

[VintageVolts]

Thanks for the additional tips, guys!

So, considering the continued flow of advice, I take it I'm not completely off my rocker for wanting to strip/rebuild/refurbish this radio?

It certainly seems daunting enough, but I'm not on any time constraint. Nor am I going to rush the job.

BTW, how do I remove the coil cans from the chassis? It looks like they're pressed on quite solidly.

[Mondial]

Personally, I think you would be a lot better off if you tried to find the problem with the radio instead of completely disassembling it. You could take all the parts off and reassemble them only to find that it still does not work.

The chances for making an error and miswiring something are also high. You could create a problem which never existed before. Also unless the metal chassis is in really poor physical shape and requires major restoration, there is always the possibility of damaging delicate parts which otherwise would be fine.

From what you describe, it sounds like you have an open winding on the oscillator coil. This will prevent any reception, although you still may hear various noises in the speaker. My advice would be to make some resistance checks of the various windings of the coil and proceed from there.

[VintageVolts]

Quite honestly, I don't want to tear this down completely, but then again, I don't want to have to be chasing problems with one fix here and one fix there if it involves unsoldering a lot of parts to get to each bad component. It's a judgement call at the moment. Since it appears that I'll have to remove many of the parts to get to some of the coils anyway, I'll consider a partial teardown. I'm still going to rebuild the capacitor blocks, since I already have the parts.

I have the chassis about 1/4 torn down and the first coil (and two capacitor blocks) out of the radio (on the side opposite the transformer). I'll look at the coil I have out now, rewind it if necessary, and continue after I receive Chuck Schwark's service packet. I may just test the coils first per your suggestion, reassemble what I removed, then test it. If it doesn't work then, I can still go for the teardown.

Thanks,
Jeff

[Mondial]

That seems like a reasonable way to proceed. Try to disassemble only one small section at a time while restuffing the blocks and checking the associated coils and resistors. Then carefully power up and check for proper operation while doing voltage measurements in that circuit section.

In this way, you minimize the chances for wiring errors and localize the cause of the problem at the same time.

[Raleigh]

I don't know if you got an answer to your question about Chuck Schwark's service packages having a point-to-point wiring diagram. The routing of some wires is considered critical in some radios, and those wires are shown in diagrams, but most are not shown. There are usually top side and under side diagrams showing the location of every component by number, but wiring is typically not shown.

I've had very good luck with the method of desoldering one or two connections at a time, replacing the paper caps, testing resistors, micas, coils, wiring, etc. Usually, but not always, the radio comes up and works after I've done this because I've already replaced or repaired the defective components without troubleshooting. Stripping the chassis isn't needed from the electronics standpoint, but if you have lots of rust or mouse filth, it might be necessary.

Some restorers don't desolder components but cut them out and splice new ones to the existing leads. I've done that on a few radios. It works OK and is a good bit less work.

PS. Except for the filament pins, none of the tube pins should be connected to any other one. I don't have a tube tester. I test for shorts just by putting an ohm meter lead on each pin in turn and then touching all the other pins. You shouldn't get a beep unless you're touching the two (occasionally three) filament pins. Of course, you need a pin-out diagram. I've found two or three tubes with shorts, but it is rare.

[Ron Ramirez]

BTW, how do I remove the coil cans from the chassis?

You don't. They were spun on at the factory; any attempt to remove them will probably ruin them.

The coils are removable from underneath. Not the shields (cans), just the coils themselves.